ACNP 61st Annual Meeting: Poster Abstracts P271-P540 (2023)

Maya C. Schumer*, Michele A. Bertocci, Haris A. Aslam, Simona Graur, Genna Bebko, Richelle S. Stiffler, Alexander Skeba, Tyler J. Brady, E. Kale Edmiston, Henry W. Chase, Sheri L. Johnson, Maria L. Phillips

University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Background:There is an urgent need to identify robust biomarkers of objective risk factors associated with bipolar disorder (BD), particularly those predictive of mania/hypomania and mixed states, as these are pathognomonic features of BD. Furthermore, the identification of future BD risk biomarkers not only informs early identification of risks and targets for treatment development, but also contributes to our understanding of the pathophysiological processes underlying BD. Impulsivity is a widely studied feature of BD that is elevated during manic and mixed episodes and persists during euthymic periods. Although impulsivity is a multifaceted trait, impulsivity triggered by emotion or rash action based on emotion is perhaps the most important form, as it is associated with a variety of important outcomes in BD, including and particularly suicidal tendencies. Negative and positive impulses (NU/PU), defined as tendencies to react impulsively in response to negative and positive affects, respectively, are evident in adults with TB and have been identified as risk factors for future TB, but studies, neuroimaging studies , o Neural correlates examining urgency associated with predicting TB risk are scarce. We previously reported negative relationships between NU and PU-related blood oxygen level-dependent (BOLD) activity in the left dorsolateral prefrontal cortex (L DLPFC) during focal emotion processing and lifetime risk of mania in a cohort. of 106 young adults seeking treatment for mental distress. However, whether L-DLPFC activity associated with urgency is a predictor of manic symptoms over time, and whether the relationship is specific to mania or also extends to depressive symptoms, remains to be tested.

Methods:Twenty-one stressed adults aged 18 to 23 years (mean age 20.84 ± 1.49, 17 women) from the above initial transdiagnostic cohort who were scanned in a 3T-fMRI while performing a processing task of facial emotion. Baseline and 12-month follow-up implicit and complete assessments of increased hypo/mania and depression, as measured by the mood, depression, and mania domains of the Mood Spectrum Scale Scale (MOODS). Activity related to the happy and angry face in the initial scan was examined using an anatomical mask of regions that support emotion processing and executive function, including the L DLPFC. Parameter estimates were extracted from separate NU and PU multiple regression models varying by age and sex, p < 0.001, uncorrected, k = 20.

We performed two separate and parallel multiple linear regression models with L DLPFC BOLD activity related to NU and PU, baseline MOODS manic mood score, age and gender as predictors, and MOODS manic mood domain score. manic mood at 12 months of follow-up as a dependent variable.

To test whether L-DLPFC was specific for predicting mania, we ran two additional multiple regression models (one for NU, one for PU) controlling for baseline depression using the 12-month MOODS score dependent on the depressive domain as a variable.

The results of both the primary analysis with mania and the specificity analysis with depression were considered significant at p<0.025 corrected by Bonferroni for two models.

Results:Baseline models with baseline demographic variables explained 18% of the variance in the 12-month MOODS manic-mood domain score. The full model, including NU-related L-DLPFC activity, was significant, F(2,16)=4.88, p=0.009, with an adjusted R2 of 0.44, making L-DLPFC 26% of the explained variance and significantly associated with mania one year later (β = -8.07, t = -2.95, p = 0.009). The complete model including PU-related L-DLPFC activity was also significant, F(2,16)=4.2, p=0.016, with an adjusted R2 of 0.39, so that L-DLPFC explained 21% of variance and Mania was significantly associated with it one year later (β = -7.24, t = -2.61, p = 0.019).

In the specificity analysis with the 12-month depressive domain MOODS score, the complete model, including the NU-related L-DLPFC activity, was not significant, F(2,16) = 3.56, p = 0.029, with a Adjusted R2 of 0.338. One year later, L-DLPFC activity was not significantly associated with depression (β = -6.24, t = -2.23, p = 0.041). The complete model, including PU-related L-DLPFC activity, was not significant, F(2,16)=3.08, p=0.047, with an adjusted R2 of 0.294. L-DLPFC activity was not significantly associated with depression one year later (β = -5.53, t = -1.91, p = 0.074).

Conclusions:Attenuated NU and PU-related L-DLPFC activation at baseline predicted changes in mania one year later, and their significant associations were indeed mania-specific. These preliminary results underscore the importance of urgency-related central executive network activity during emotion processing in predicting changes in manic symptoms over time, indicating an increased risk of future tuberculosis. Future research should extend these results to a larger sample and assess whether these markers can further predict conversion to DB in at-risk individuals, as well as exploring the potential of targeting L DLPFC for therapeutic interventions.

Key words:Bipolar disorder, mania, dorsolateral prefrontal cortex, negative impulses, emotion processing

Disclosure:Nothing to disclose.

Nausheen Baig*, Kyle Decker, Stephen Murata, Debra Hoppensteadt, Jawed Fareed, Angelos Halaris

Loyola University Chicago Stritch School of Medicine, Oak Brook, Illinois, EUA

Background:Inflammation has been associated with major depressive disorder and treatment resistance (Haroon and Miller, 2017; Miller et al., 2009), leading to the search for predictive biomarkers of treatment response. In a randomized, double-blind, placebo-controlled study, we demonstrated the efficacy of escitalopram (ESC) + celecoxib (CBX) compared to ESC + placebo (PBO) in TRBDD (in this secondary analysis we characterized response to treatment (HAMD17) in relation to SIRI (monocytes x neutrophils/lymphocytes) Our hypothesis is that response to treatment with ESC + CBX is associated with baseline and/or changes in SIRI levels.

Methods:The sample (N = 79) included healthy controls (n = 32) and TRBDD subjects (n = 47). The TRBDD cohort included an ESC + CBX arm (n = 26) and an ESC + PBO arm (n = 21). The SIRI was calculated from a complete blood count (CBC) obtained at baseline and at the end of treatment (week 8). Inflammatory biomarkers were measured by ELISA assays. Kynurenine (KP) pathway metabolites were measured by HLPC. HAMD17 scores were obtained weekly. Treatment remission was defined as HAMD17 < 7 at week 8 of treatment. Univariate correlations between SIRI and inflammatory biomarkers and KP were examined. Post-treatment HAMD17 was modeled according to treatment arm, baseline HAMD17, baseline SIRI, and relevant interactions using multivariate linear regression. Statistical analysis was performed using R-3.6.3.

Results:In the TRBDD sample (n=47), there were n=14 (38%) remitters at week 8. Remission was significantly associated with ESC+CBX treatment (X2=8.3, p=0.004). Comparison of group by treatment group revealed no difference in gender, BMI, or blood count; however, patients in the CBX + ESC arm were older (p = 0.032).

In univariate analysis of baseline SIRI, there were no significant correlations with treatment response at week 8 (measured as continuous or categorical outcome), although baseline SIRI did correlate with baseline HAMD17 (p=0.008). Baseline IRIS was significant with higher levels of TNF-alpha at week 8 (p=0.007) and IL-2 at baseline (p=0.053), elevated picolinic acid both at baseline (p=0.034) and at week 8 (p=0.037) and lower 3-hydroxykynurenine at week 4 (p=0.030). Notably, baseline SIRI also tended to significantly correlate with lower baseline IL-4 (p=0.057) and higher baseline anthranilic acid (p=0.071).

Multivariate analysis showed that HAMD17 was significantly associated with IRIS at week 8, adjusting for treatment arm (beta=5.74, p = 0.007, adjusted R2/R2=0.553/0.531). Finally, HAMD17 at week 8 was significantly associated with ESC + CBX treatment (p < 0.002) and an interaction with baseline SIRI and baseline HAMD17 (estimate β = 8.3 [95% CI (0.23, 1.44)] , p = 0.008) (R2 /adjusted R2 = 0.354/0.286).

Conclusions:Post-treatment HAMD17 was predicted regardless of treatment arm and baseline interaction of SIRI with HAMD17. This suggests that, although baseline SIRI is not an independent predictor of response to treatment, it may indicate a poor prognosis in patients with increased severity of pretreatment depression. It should be noted that this association is not treatment-arm dependent. Given the associations with pro-inflammatory markers and KP metabolites reported here, it is plausible that the biological significance of SIRI could implicate these signaling pathways. Future studies of SIRI with a larger sample size are needed to clarify its potential role as an easily obtained/accessible predictive biomarker of treatment response in TRBDD.

References:

Halaris A., Cantos A., Johnson K., Hakimi M. & Sinacore J. (2020). Modulation of the inflammatory response benefits treatment-resistant bipolar depression: a randomized controlled trial. Journal of Mood Disorders, 261, 145-152.https://doi.org/10.1016/j.jad.2019.10.021

Haroon, E. & Miller, A.H. (2017). Effects of inflammation on glutamate as a pathway for neuroprogression in mood disorders. Modern Trends in Pharmacopsychiatry, 31, 37–55.https://doi.org/10.1159/000470805

Mazza, MG, De Lorenzo, R, Conte, C, Poletti, S, Vai, B, Bollettini, I, Melloni, EMT, Furlan, R, Ciceri, F, Rovere-Querini, P and Ampere; Benedetti, F. (2020). Anxiety and depression in COVID-19 survivors: role of inflammatory and clinical predictors. Brain, Behavior and Immunity, 89, 594-600.https://doi.org/10.1016/j.bbi.2020.07.037

Mazza MG, Palladini M, De Lorenzo R, Magnaghi C, Poletti S, Furlan R, Ciceri F, COVID-19 BioB Ambulance Study Group, Rovere-Querini P, & Benedetti, F. (2021). Persistent psychopathology and neurocognitive impairment in COVID-19 survivors: effect of inflammatory biomarkers at three-month follow-up. Brain, Behavior and Immunity, 94,138-147.https://doi.org/10.1016/j.bbi.2021.02.021

Miller, A.H., Maletic, V. & Raison, CL (2009). Inflammation and its dissatisfaction: the role of cytokines in the pathophysiology of major depressive disorder. Biological Psychiatry, 65(9), 732-741.https://doi.org/10.1016/j.biopsych.2008.11.029

Zahorec, R. (2021). Ratio of neutrophils to lymphocytes, past, present and future perspectives. Bratislavske Lekarske Listy, 122(7), 474-488.https://doi.org/10.4149/BLL_2021_078

Zhang Y, Xing Z, Zhou K and Jiang S (2021). The predictive role of the systemic inflammatory response index (SIRI) in the prognosis of patients with stroke. Clinical Interventions in Aging, 16, 1997-2007.https://doi.org/10.2147/CIA.S339221

Key words:Bipolar I depression, systemic inflammation, neuroprotection, neuropharmacology

Disclosure:Nothing to disclose.

Jungwon Cha, Amit Anand*

Harvard Medical School, Boston, Massachusetts, EUA

Background:Connectivity changes between networks are part of the dynamic changes in the configuration of the brain as it interacts with the environment. Therefore, a continuous design more closely matches actual conditions. Furthermore, changes in network connectivity are more consistent with brain function as it is reconfigured for different conditions of emotion regulation rather than a static measurement during a single state. We developed a new resting-state fMRI paradigm: the continuous performance emotion regulation task (CERT) to capture brain network reconfiguration during emotion regulation. This study used group-level CERT and Independent Component Analysis (ICA) to examine differences in changes in intereuronal network connectivity during maintenance and regulation of negative emotions to distinguish between (i) bipolar depression (BDD) and major depressive disorder ( MDD). (ii) patients (PA = BDD + MDD) and healthy controls (HC) and (iii) high-risk (HRRMDD) and low-risk (LRMDD) MDD patients of bipolar disorder.

Methods:Subjects: Data are from a large sample of N = 298 drug-free participants recruited from psychiatric outpatient clinics at the Indiana University School of Medicine and the Cleveland Clinic and through advertising. All participants with BDD and MDD had to be drug-free for at least 2 weeks. The final analysis included 249 participants: 50 BDD (18 BDI, 32 BDII), 116 MDD (35 HRRMDD, 45 LRMDD, 36 unspecified); and 83 HC subjects.

CERT Imaging: The fMRI data were acquired under two different conditions: during separate sessions of 5.25 minutes each, subjects were continuously shown negatively rated images while trying to maintain an emotional response to the images or trying to suppress their emotional response in the next sentence . apply processing techniques. Data collected from each run were corrected for motion and physiological noise and filtered to keep frequencies between 0.008 and 0.08 Hz.

Network Connectivity: Analysis: A group-level independent component analysis (ICA) was performed using the GIFT toolbox. Resting pre-processed functional MR images of all subjects for maintenance (249 images) and regulatory (249 images) states were decomposed into independent components. Fourteen independent components were selected for the resting state network (RSN), including the dorsal and ventral default mode networks (dDMN and vDMN), the anterior and posterior prominence networks (ASN and VSN), the right executive control network and left (ECN ), the sensorimotor network (SMN) ), the precuneus network (PN), the visual and auditory networks (VN and AN) and the language network (LN). With the selected set of components, univariate tests were performed to determine the difference between the network connectivity between each individual group (BD, MDD, HRRMDD, LRMDD, PA and HC) under the two different conditions (maintenance vs. normal) via repetition ANOVA (RMANOVA).

Results:Condition Effect: Within the cluster: HC, MDD and LRMMD showed differences in connectivity changes between networks during maintenance and regulation conditions for different pairs of networks, including DMN and SN. However, the BDD and HRMDD groups showed no significant change in connectivity between the two states.

Group x condition effect:

1. one.

   The group-state interaction BDD vs. MDD was significant (FDR corrected to p < .01) for inter-network connectivity between SMN-AN, SN-ECN and SN-VN.

2. b.

   PA vs. HC: The group-state interaction showed a significant difference (FDR corrected to p < .01) in several FNC pairs, including vDMN-AN, dDMN-AN and dDMN-ECN correlations.

3. C.

   HRMDD vs. LRMDD: A significant interaction between group and state was observed for connectivity between AN-VSN networks (p < 0.01, uncorrected).

Group effect: No differences were observed between each group in terms of maintenance and withdrawal.

Conclusions:Using a new continuum paradigm of emotion regulation and maintenance, differential connectivity changes between differentiated networks between depressed individuals and healthy controls, MDD and BDD groups, and depressed individuals at high and low risk for bipolar disorder. Therefore, changes in network connectivity across emotion regulation conditions, rather than a static measure of network connectivity across a single condition, may serve as a more efficient biomarker of depression and depression subtypes.

Key words:Brain networks, dynamic functional connectivity, task continuous performance, affect regulation, depression

Disclosure:Nothing to disclose.

Sarah Sperry*, Paul Jenkins, Kelly Ryan, Ivy Tso, Melvin McInnis

University of Michigan, Ann Arbor, Michigan, USA

Background:Bipolar disorder (BD) is a complex, multidimensional illness characterized by pathological changes in mood and emotions that change over time. The etiology of TB is unknown, but causality is considered plural. The HC Prechter Bipolar Research Program at the University of Michigan is a collaborative network of research projects focused on discovering the mechanisms underlying the etiology of BD and studying patterns that predict disease outcomes. Key program features include in-depth phenotyping and continuous longitudinal collection of clinical data. Data are organized into 7 ontological platforms: 1) neurocognitive function; 2) personality, 3) motivated behavior; 4) sleep and circadian patterns; 5) life history and experiences; 6) treatment patterns and outcomes; 7) disease states.

Methods:There are currently 1385 participants in Prechter's cohort (mean enrollment age 39.2 years, 62% female), including 874 subjects with BD and 282 controls. The median longitudinal follow-up is 9 years (range: 0-16). Deep Clinical Phenotyping collects clinical data from each of the 7 ontological platforms. Standardized interviews, rating batteries, and self-report questionnaires are used to assess neurocognitive function (e.g., visual memory, fine motor skills), personality (e.g., NEO PI-R), and motivated behaviors (e.g., test of identification of alcohol use disorder). to assess), sleep and circadian rhythms (eg, PSQI, Munich Chronotype Questionnaire), life history (eg, Life Event Checklist, Trauma Questionnaire), patterns of care, and outcomes (eg, medication review, mood measurements ). Biological modeling of disease states uses induced pluripotent stem cell (iPSC) methods. To identify patterns between baseline characteristics and the longitudinal course of the disease, we used multilevel modeling, dynamic structural equation modeling, pathway analysis, and mathematical modeling approaches.

Results:We present the main results of each of the ontological platforms in this article. Neurocognitive function: Individuals with BD have lower cognitive performance in visual memory (t=3.31, p=001) and fine motor skills (t=4.21, p<001) at baseline and 5-year UPS compared with controls. However, there is no overall difference in the rate of neurocognition decline between BD and controls. Personality: People with TB have higher levels of neuroticism that remain stable over time. The stability of neuroticism over time has a moderately strong association with depression (effects range from 0.21 to 0.52, ps < 0.001). Motivated behavior: People with TB tend to increase their alcohol consumption over time (Est = .33, 95% credible range [.30, .35]). Increased alcohol consumption appears to increase the risk of depression 6 months later (Est = .04, 95% CI [0.02, 0.07]) and greater mood swings in the following year (Est = .12, CI 95 % [0.05, 0.18]). Even low alcohol consumption predicted more impairment of friendships (β = 0.01, p = 0.02) and work-related functioning ((β = 0.01, p = 0.04). Estimates seem to influence the results longitudinal studies, with those who identify as a late chronotype experienced a higher frequency of depressive symptoms over time (Est = 1.29, 95% CI [1.14, 1.47]), attachment, and current romantic attachment in context of a traumatic childhood history were associated with greater depression severity (accounting for 12% of the total effect of childhood trauma on depression severity) Patterns of Treatment and Outcome: Mathematical modeling of longitudinal mood data suggests that people with BD are characterized by significant affective instability with regard to mood do not follow a consistent process TB episodes arise in the context of persistent instability caused by failure once disturbed to return to normal states. and synaptic in iPSC cells differs significantly between BD and controls (p<0.05); Exosomal source/load significantly affects synaptic activity. The addition of control-derived exosomes significantly increases synaptic density in bipolar-derived neurons (iPSCs) (p<0.01).

Conclusions:We identified 7 ontological platforms that are critical to understanding longitudinal course and heterogeneity in DB. Baseline characteristics on these platforms appear to strongly predict the severity and progression of depressive symptoms. The organizational structure of the data benefits from considering an ontological approach to studying static, categorical, and longitudinal dynamic characteristics of diseases. There are biological, neurocognitive, personality, behavioral, sleep, life history, and outcome differences when comparing BD with controls and in individuals with bipolar disorder, providing the basis for examining underlying mechanistic differences in disease subtypes. Future research with the HC Prechter Bipolar Research Program aims to use data-driven approaches to identify strata of individuals based on these 7 ontological platforms to implement personalized and precision medicine-based interventions.

Key words:Bipolar Disorder, Longitudinal Study, Deep Phenotyping, Mood and Cognition

Disclosure:Nothing to disclose.

Steven Lamontagne*, Jessica Gilbert, Carlos Zárate, Elizabeth Ballard

National Institute of Mental Health, Bethesda, Maryland, USA

Background:Suicide is one of the leading causes of death worldwide, causing at least one million deaths each year (World Health Organization, 2021). Despite rising suicide rates, risk reduction strategies have largely failed. Two major barriers hamper these efforts: (1) a lack of objective markers to study suicidal states, which limits suicide research to self-reports, and (2) a limited understanding of the neurobiology of suicide, which makes it difficult to develop interventions. While progress has been made on these fronts, there is considerable heterogeneity in the characterization of suicide risk across clinical trials and neuroimaging studies. Therefore, there is an urgent need to identify neural correlates associated with differential suicide risk and to develop new, fast-acting therapies to modulate activity within these neural networks.

Methods:75 adult men and women (Mage = 39.89, range 19-65) were recruited through a suicide-focused research protocol (NCT02543983). Although most studies define suicide risk broadly based on lifetime histories of attempts, we examined parameters along a risk continuum: (1) those with a suicide attempt within the past 2 weeks and/or suicidal ideation lifetime (high risk). 🇧🇷 HR) (n = 15), (2) individuals with a history of attempting but no suicidal thoughts or intentional behavior in the past year (moderate risk; MoR) (n = 18) (3) individuals with anxiety or mood symptoms but no history of suicide (low risk; LR) (n = 19) and (4) subjects with no psychiatric history or suicide (minimum risk; MinR) (n = 23). We used a 275-channel CTF full-head magnetoencephalography (MEG) scanner to examine the electrophysiological correlates of suicide. During the MEG scan, participants completed a modified life-death implicit association task, which is a computer task that measures a person's associations with life and death based on reaction times to the words they represent. Each category (faster response time means more implicit bias). (Nock et al., 2010). The behavioral outcome of interest was the D-score, defined as the difference in mean reaction times between the suicide and self-life tests divided by the standard deviation of all tests (positive D-scores reflect a stronger association with suicide ). 🇧🇷 🇧🇷 🇧🇷 MEG data were localized to the source at frequency gamma (30-58 Hz), an indirect measure of excitation-inhibition balance, using a 1 s window from word initiation and a linearly constrained minimum-variance beamforming algorithm were used. A linear mixed-effects model implemented in AFNI was used to assess differences in gamma strength between personal life and personal death word pairs. As an open-label proof-of-concept pilot study, we evaluated the effects of subanesthetic doses of ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist known for its rapid antisuicide properties, on gamma strength in a small group of study participants. RH (N = 5).

Results:The behavioral results showed that the D scores in the HR group did not deviate from zero (p=0.78), but were significantly higher compared to the MoR, LR and MinR groups (ps<0.01) . D scores for the last three groups were not different from each other (ps > 0.43) and were significantly less than zero (ps < 0.001), indicating a self-life bias. In all groups, a linear mixed-effects model showed increased gamma power for suicide compared to self-living conditions in the posterior cingulate cortex (PCC) (p < 0.05), a region associated with self-referential processing. A significant group-condition interaction (p < 0.05) revealed group differences in gamma power within the PCC, right insular cortex, and orbitofrontal cortex (OBF). Extraction of gamma power estimates in these regions showed higher gamma power for suicide compared to self-life tests on the OBF for the HR group (p <0.01) and on the insula and PCC for the MinR group (ps <0.05 ). For the LR group, there were no differences in gamma strength between own life and own death attempts (ps > 0.05). In the ketamine pilot study, D values ​​were unaffected by ketamine administration (p=0.57); however, a session-condition interaction (p<0.05) showed improved gamma performance for suicide test in the left insula after ketamine administration compared to baseline (p<0.001). Gamma insular performance after ketamine for suicide studies was inversely correlated with D-score (r = -0.89, p <0.05), suggesting that the insula is an important biomarker of implicit cognitions about death in individuals with human Resources.

Conclusions:These results indicate differential implicit cognitive processing of life and death based on suicide risk and underscore the need for patient-centered risk assessment in suicide prevention. Our results also suggest a role for pharmacotherapies that modulate gamma activity, particularly in the PCC and insula, in reducing risk. To that end, our preliminary data show promising effects of ketamine in modulating the neural correlates of suicidal cognitive processing.

Key words:Suicide risk factors, implicit association test, ketamine, magnetoencephalography

Disclosure:Nothing to disclose.

Kristen Eckstrand*, Erika Forbes, Michele Bertocci, Henry Chase, Jeanette Lockovich, Richelle Stiffler, Haris Aslam, Alex Skeba, Simona Graur, Genna Bebko, Mary Phillips

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:The COVID19 pandemic has resulted in significant morbidity and mortality, including worsening mental health due to increased severity of depression and anxiety. Young adults' experiences during the pandemic, such as social isolation and increased stress, limit exposure to rewarding experiences and are associated with poor mental health. Altered connectivity between reward neural regions such as the ventral striatum (SV), dorsal anterior cingulate cortex (dACC) and ventrolateral prefrontal cortex (vlPFC) with other neural regions involved in highlight recognition and executive control has been reported. com Linked to depression and anxiety. and may be a mechanism by which the COVID19 pandemic has exacerbated affective and anxiety symptoms in young adults. The purpose of this cross-sectional study was to examine whether the COVID19 pandemic altered the relationships between neural reward connectivity and affective and anxiety symptoms.

Methods:Ninety-eight young adults (23.5 ± 2.9 years; gender 63 F/35 M) were enrolled in this cross-sectional substudy, derived from a larger longitudinal study that examined the development of mood and anxiety symptoms later in life. Participants were divided into two pandemic groups, those who completed the study before the COVID19 pandemic (n=39) and during the pandemic (n=59), using the national cut-off date (March 13, 2020). Participants completed self-reports on depression (Mood and Anxiety Symptoms Questionnaire (MASQ) - Anhedonia Depression), anxiety (MASQ - Anxious Arousal), anhedonia (Snaith Hamilton Pleasure Scale), lifetime trauma exposure (Historical Trauma Questionnaire) and underwent an fMRI during a standardized monetary reward task. The fMRI data was pre-processed with fMRIPrep 20.2.6 and first level analyzes were completed in SPM12. The first-level GLM included reward expectancy (RE), reward prediction error (RPE) and uncertainty expectation (UE) as covariates. Whole-brain functional connectivity during ER and RPE was assessed using bilateral VS seeds, dACC (Brodmann area 32) and vlPFC. Six second-level models with two clusters (3 seeds x 2 connectivity conditions) were run on SPM12 to compare neural connectivity between COVID19 pandemic clusters. Each model included independent variables of self-reported depression, anhedonia, and anxiety that interacted with the pandemic group. Age, gender, IQ, psychotropic drug exposure, bipolar diagnosis, and lifetime exposure to trauma were included as covariates. Significance was defined as punc < 0.001 in SPM12, group corrected in pFWE < 0.05.

Results:Participants who completed the study during the COVID19 pandemic reported greater severity of anhedonia (t=-2.112, p=0.019) and anxiety (t=-2.789, p < 0.003), but not depression. the COVID19 pandemic. The COVID19 pandemic affected the associations between mood symptoms and connectivity of ACC and vlPFC during RE and RPE. During RE, lower dACC-mPFC connectivity (kE = 108 voxels, pFWE = 0.015) was associated with greater severity of anhedonia during the COVID19 pandemic compared with lower severity of pre-COVID19 anhedonia. Inferior vlPFC connectivity with left cerebellum (kE=131 voxels, pFWE=0.009), bilateral thalamus (kE=165 voxels, pFWE=0.002), right parietal lobe (kE=171 ​​voxels, pFWE=0.002), middle cingulate cortex ( kE = 94 voxels, pFWE = 0.044) and right precentral gyrus (kE = 133 voxels, pFWE = 0.008) during ER was associated with greater anxiety severity during the COVID19 pandemic compared with lower anxiety severity before the COVID-19 pandemic. COVID-19. During RPE, vlPFC connectivity increased for the right temporoparietal junction (kE = 119 voxels, pFWE = 0.022), the right dorsomedial prefrontal cortex (kE = 176 voxels, pFWE = 0.003), dACC (kE = 98 voxels, pFWE = 0.002), and the middle cingulate cortex (kE = 181 voxels, pFWE = 0.002) during RPE was associated with greater severity of anhedonia during the COVID19 pandemic compared with lower severity of anhedonia before the pandemic. Greater connectivity of the ACC with the left vlPFC (kE = 169 voxels, pFWE = 0.001) and the right ventral postcentral gyrus (kE = 144 voxels, pFWE = 0.003) was associated with greater anxiety severity during the COVID19 pandemic compared to lower severity of anxiety previously linked to the COVID19 pandemic.

Conclusions:The COVID19 pandemic has shifted the direction of associations between anhedonia and anxiety severity and reward circuit connectivity. Increased anhedonia severity was associated with reduced dACC connectivity to highlighted regions during RE and increased vlPFC connectivity to the central executive network during RPE, suggesting a reduced ability to anticipate rewards and upregulation of the reward response may have contributed to a greater severity of anhedonia during the pandemic. The opposite pattern was evident in anxiety states, where greater anxiety severity was associated with a combination of lower vlPFC connectivity to the central executive network during ER and greater ACC connectivity to prominent regions during RPE. This indicates a decreased ability to appraise and pay attention to potential rewards, combined with an increased sensitivity to rewards, which influenced the severity of anxiety during the pandemic. The combined, opposing, and ineffective compensatory relationships between reward circuits and central highlighting and executive networks during the pandemic may be a mechanism for the increased severity of anxiety and depression observed during the pandemic.

Key words:The COVID-19 Pandemic, Reward Cycle, Depression and/or Anxiety, Young Adults

Disclosure:Nothing to disclose.

Michele Bertocci*, Yvette Afriyre-Agyemang, Satish Iyengar, Renata Rozovsky, Richelle Stiffler, Haris Aslam, Genna Bebko, Mary Phillips

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:A variety of subsyndromal and syndromic affective symptoms underlie emotional distress and are often early predictors of future depression in young adults. Increased functional connectivity (FC) between the core executive network (CEN), supports emotion regulation (ER) subcomponent processes such as working memory (WM), default mode network (DMN), supports processing of self-related information and the salience network (SN), which is believed to disrupt cognitive function and predispose to depressive disorders. These neural network patterns are therefore potential early and targeted neural markers of depressive disorders; However, few studies have examined how activity within and HR between these neural networks during WM and ER tasks is associated with depression severity in young adults. Our aim was: 1. to elucidate the relationships between activity and HR in these networks and concomitant depression, using a paradigm developed to examine MO and RE capacity; 2. Examine the extent to which these relationships were specific for depression versus mania/hypomania; 3. test whether the results of a first "discovery" sample can be replicated in a second "test" sample of young adults; and 4. to test whether such relationships also predicted future depression and/or mania/hypomania severity.

Methods:We examined the relationships between concurrent depression and the severity of mania/hypomania and CF and neural activity during the above paradigm in two independent samples of young adults: a discovery sample: n=90, 60 women, age=21.7 (2, 0) and a test sample: n = 96, 65 women, age = 21.6 (2.1). Depression severity was assessed using the Hamilton Depression Rating Scale and mania/hypomania severity using the Young Mania Rating Scale. We examined activity and HR using an emotion regulation neural mask that includes key regions in each network: the dorsolateral prefrontal cortex and the caudate in the CEN; precuneus in the DMN; and the dorsal anterior cingulate cortex and amygdala in SN (FWE p = 0.001, k > 10). Elastic network variable selection was performed using GLMNET, followed by negative binomial regression to determine relationships between groups of significant activity and HR in this mask and the concomitant severity of depression and mania/hypomania in the uncovered sample. Negative binomial regression analyzes determined whether significant neuronal activity and affective symptom-HR relationships in the discovery sample were replicated in the test sample. We then examined the relationships between neural activity and heart rate and future depression and mania/hypomania severity in a subsample drawn from both samples (n = 61, 45 women, age = 21.6 (2.1)) who were until The examination was clinically evaluated until 12 months later.

Results:In the discovery sample during working memory: dlPFC activity (odds ratio (OR): 1.80, CI: 1.42-2.28, qFDR <0.001), precuneus activity (OR: 1.43, CI: 1 0.12–1.82, p = 0.004, qFDR = 0.004) were positively associated with the severity of co-occurring depression. These relationships were replicated in the test sample: dlPFC activity (OR: 2.90, CI: 2.31-3.64, qFDR < 0.001) and precuneus activity (OR: 1.88, CI: 1.54-2 , 29, qFDR   < 0.001). These measures were also positively associated with future depression severity: dlPFC activity (OR: 2.81, CI: 2.21-3.56, qFDR <0.001) and precuneus activity (OR: 1.49, CI: 1, 21-1.85, qFDR <0.001). In sample detection during emotion regulation: dlPFC activity (OR:4.27, KI:2.09-8.72, qFDR <0.001), Precuneus-dACC FC (OR:1.64, KI:1.06- 2.53, qFDR = 0.046), precuneus - dlPFC HR (OR: 1.67, CI: 1.22–2.29, p = 0.002) and dlPFC-dACC HR (OR: 1.49, CI:1 0 .09–2.04, qFDR = 0.028) were also positively associated with depression severity. These relationships were replicated in the test sample: dlPFC activity (OR:2.65, CI:1.94-3.63, qFDR <0.001), Precuneus-dACC FC (OR:11.22, CI:7.26- 17.34, qFDR<0.001) and dlPFC - FC positive for dACC (OR: 2.61, CI: 1.89-3.60, qFDR <0.001). These measures were also positively associated with future depression severity: dlPFC activity (OR: 3.55, CI: 2.52-5.0, qFDR <0.001) Precuneus-dACC FC (OR: 6.26, CI: 3, 62–10.83, qFDR <0.001) and dlPFC-dACC FC (OR: 3.65, CI: 2.34–5.68, qFDR <0.001). There were no relationships between neural readings and the concomitant severity of mania/hypomania in the Discovery sample.

Conclusions:Identification and replication of large-scale neural network predictors of concurrent and future depression severity across working memory and emotion regulation paradigms is a step towards identifying objective risk markers for future depressive disorders and may provide neural targets to better guide and monitor early risk interventions. young adults.

Key words:Mood disorders, emotion regulation, fMRI working memory, default mode network (DMN), salience network

Disclosure:Nothing to disclose.

Shuken Boku*, Hiroyuki Toda, Minori Koga, Naoto Kajitani, Minoru Takebayashi

Kumamoto University, Kumamoto, Japan

Background:As major depressive disorder (MDD) affects a patient's life for a long period of time, early detection of MDD is essential to minimize the loss and suffering of MDD. However, early detection of MDD remains difficult due to the lack of clinically useful biomarkers for MDD. Many studies have shown that early life stress (ELS) is involved in vulnerability and resilience to treatment for major depressive disorders in adults. Furthermore, recent studies have reported that miRNAs may be involved in the biological effects of ELS. This suggests that ELS-associated miRNA could be a potential biomarker for MDD. Therefore, here we investigated the possibility of ELS-associated miRNAs as MDD biomarkers.

Methods:Potential miRNA candidates associated with ELS were identified using maternal neonatal separation (NMS) in mice, a common animal model for ELS. Peripheral blood miRNA levels of MDD patients (N=64) and healthy controls (N=75) were estimated using quantitative RT-PCR. Receiver operating characteristic (ROC) curve analysis was performed to estimate the probability of possible miRNA candidates associated with ELS.

Results:We performed a microarray analysis of miRNAs derived from the peripheral blood of NMS mice and identified four miRNAs that were significantly altered in NMS mice and were expressed in mice and humans. ROC analysis showed that the area under the curve (AUC) of each miRNA was less than 0.7000, implying that each miRNA has limited diagnostic value for MDD. However, the AUC of the combination of these four miRNAs was 0.9444 with a sensitivity of 0.8750 and specificity of 0.9200, which means that the combination of these four miRNAs has high diagnostic power for MDD.

Conclusions:The combination of the four ELS-associated miRNAs is expected to be a clinically useful biomarker for MDD.

Key words:Major Depression (MDD), Biomarker, miRNA, Early Life Stress (ELS)

Disclosure:Nothing to disclose.

Bianca Leonard*, Steven Granger, Joren Adams, Liv McMillan, Michael Yassa

University of California Irvine, Irvine, California, USA

Background:The paraventricular nucleus of the thalamus (PVT) is gaining attention for its role in integrating landmark experiences, mediating motivational conflicts, retrieving long-term fearful memories, and regulating behavior. The PVT responds to prominent positive and negative valence stimuli, likely due to its reciprocal connections with the nucleus accumbens (NAc) and amygdala (AMY). Recently, our laboratory defined the resting-state functional connectivity (RSFC) patterns of PVT in humans using fMRI in the resting state and found that a PVT network similar to that found in rodents exists in humans. Disruption of the PVT-AMY-NAc circuit in rodents is associated with depression- and anxiety-like behaviors in rodents, specifically sex-related anhedonia. Here, we examined whether anhedonia was associated with changes in PVT-NAc and PVT-AMY RSFC.

Methods:We collected self-reported depression and anxiety scores (Beck-II Depression Inventory and Beck Anxiety Inventory) and resting-state functional magnetic resonance imaging (fMRI) in a human sample (n = 63, 48 women) supporting a variety of severity of depression and anxiety symptoms. Latent factor analysis applied to depression and anxiety symptom scores, classes of symptoms empirically differentiated in this sample. We obtained four latent factors from this analysis, including an anhedonia factor. RSFC was calculated as a time series correlation between PVT activity with AMY and NAc. PVT-NAc and PVT-AMY HR were correlated with anhedonia factor scores using Spearman's correlation coefficient.

Results:PVT-NAc HR was positively associated with anhedonia factor scores in participants with psychiatric symptoms (PS, R=0.34, p=0.018), but not in participants without psychiatric symptoms (NPS, R=0.23, p=04 ). Men had a significantly positive relationship between PVT-NAc HR and anhedonia (R=0.65, p=0.0082), but women did not (R=0.13, p=0.38). PS men had the strongest correlation between PVT-NAc HR and anhedonia factor scores (0.77, p=0.0054), whereas women did not reach significance (R=0.3, p=0.075). PVT-AMY and anhedonia factor scores were not significantly correlated between any of these analyses.

Conclusions:These results suggest that changes in the PVT-NAc circuit may be related to the severity of reported anhedonia and support the use of latent factor analysis to better understand patient reports and categorization of symptoms. Future work will include analyzes to examine whether this is gender-specific and to test the remaining factors collected in the PVT FC study.

Key words:Paraventricular nucleus of the thalamus, resting state functional connectivity, anhedonia, gender effects, latent factor analysis

Disclosure:Nothing to disclose.

Angela Ianni*, Beatrice Langer, Michael Hallquist and Alexandre Dombrovski

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:The decision to attempt suicide may result from a diminished ability to choose between alternative options when in a state of intense negative emotion. Personality traits such as neuroticism and impulsivity have been linked to suicidal behavior, and mood-related impulsivity (urgency) may play an important role in suicidal crises, but little is known about how suicidal predispositions affect decision-making. Reinforcement learning provides a framework for behavioral and neural studies of the interface between personality factors and decision making. Exploration and exploitation decisions are an example where the decision is to use known information to explore (exploit) an option known to be good or to explore other lesser known options. Optimal behavior requires proper learning from sampled rewards and proper generation and comparison of alternative options. Although previous work has linked suicidal behaviors with impaired reward-oriented learning, the neural basis of aberrant decision-making in acute suicidal crises is not well understood.

The dorsal attention network (DAN) is involved in the voluntary guidance of visuospatial attention, which allows generating a range of actions that can be taken in a given situation. The ANL consists of several functionally connected brain regions, including the intraparietal sulcus, the superior precentral sulcus, the inferior precentral sulcus, and the motion-sensing area MT complex (MT + ). Previous work in the lab has shown that these subregions play distinct roles in exploration-exploration decision-making behavior. Furthermore, computer models suggest the importance of effective information compression to limit cognitive load and optimize exploratory exploration decision-making behavior. Parameters used to characterize reward-driven learning and decision-making in this type of task include entropy (a measure of information content), change in entropy, and reward prediction error. We hypothesized that UPPS negative urgency and lack of intentional personality dimensions would be related to deviant behavior and neural DAN activity during exploration and exploration decision-making.

Methods:146 cognitively intact individuals, aged 49 to 80 years, were recruited from four groups: healthy volunteers and three groups with depression (previous suicide attempt, suicidal thoughts but no suicide attempts, and no suicidal thoughts or suicide attempts ). Subjects completed several cognitive and personality assessments, including the UPPS-P Impulsive Behavior Scale. The negative urgency subscales (tendency to act rashly in the face of extreme negative emotions) and lack of intention (tendency to act rashly) were used for image analysis due to the suspected association with suicidal behavior.

Subjects also completed an exploratory and exploratory "clock task" during an fMRI in which action scores were varied over a continuous interval characterized by visual-spatial and temporal cues. Participants were instructed to explore the range extensively to discover the most rewarding options. We used the SKEPTIC Selective Maintenance Reinforcement Learning Model developed earlier in the lab to calculate trial-by-trial action scores at discrete time intervals, reward prediction error, entropy (a measure of information content), and change in entropy. We used the Matlab VBA toolbox for model fitting and extracted test-by-test parameter values ​​for model-based fMRI analysis. The fMRI images were pre-processed and then signals from four ROIs from the DAN subregion (premotor, caudal posterior parietal cortex, rostral posterior parietal cortex and MT + ) were extracted and unfolded using a deconvolution algorithm Leading hemodynamics for estimating neural activity stimuli and averaging assays. Multilevel modeling implemented in R was used to test the significance between behavioral parameters derived from the model and neural data, with a significance threshold of p<0.05, corrected for FDR.

Results:We found a positive effect of negative UPPS urgency on neural response to an increase in the number of potentially useful options in all DAN regions (all p<0.05, corrected for FDR), with the greatest effect in the posterior caudal parietal cortex. This effect remained significant across regions when age, education, total UPPS, and anxiety diagnosis were controlled for. Furthermore, we found that negative urgency was also positively correlated with responses to unsigned prediction errors (surprise) in the caudal posterior parietal cortex and MT + , but not in other DAN regions when compared with age, education, total UPPS, and diagnosis of anxiety were checked. Mood-independent impulsivity, measured with unintentional UPPS, did not modulate DAN reinforcement coding.

Conclusions:Mood-related impulsivity is associated with exaggerated responses to reinforcement when the best option is more difficult to identify. This heightened sensitivity to global uncertainty may represent a neural mechanism underlying aberrant decision-making in a suicidal crisis.

Key words:Exploit-exploit dilemma, computational decision-making models, impulsivity, suicide

Disclosure:Nothing to disclose.

Benjamin Wade*, Tracy Barbour, Kristen Ellard, Joan Camprodón

Massachusetts General Hospital, Charlestown, Massachusetts, USA

Background:Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression. To date, however, few studies have examined whether the antidepressant response to rTMS is predictable using pretreatment imaging. Depression is also a symptomatically heterogeneous disorder. Previous work by our group has shown that prospective prediction of antidepressant response to other antidepressant treatments (i.e., ketamine and ECT) is improved by predicting changes in symptoms along latent dimensions of depression rather than changes in overall symptom severity. depressants. Here, we compare the performance of machine learning models using resting-state functional connectivity (RSFC) pretreatment patterns in predicting rTMS-related symptom changes in Hamilton Depression Rating Scale (HDRS) total score. of 17 items, the HDRS-6 subscale, and three previous ones identified latent dimensions of HDRS: core mood and anhedonia (CMA), somatic disturbances (SoD), and insomnia. We hypothesize that the predictions of changes in the CMA and HDRS-6 dimension would be more accurate than those of the full HDRS-17.

Methods:Patients (n = 26; mean [SD] age = 41.1 [14.1] years; percentage of men = 50%) received rTMS in the left DLPFC. Stimuli were delivered at 120% of resting motor threshold at 10 Hz (3000 stimuli per session, 36 sessions in total). All patients underwent resting-state fMRI (rs-fMRI) within one week of the first rTMS session, and depressive symptoms were assessed using HDRS-17 every 2 weeks, including the first and last day of treatment. Pretreatment rs-fMRI scans were divided into 200 regions using Schaefer's atlas. For each subject, regional global connectivity scores were calculated using the graph's theoretical node degree, calculated as the sum of paired correlations surviving a Fisher Z-transformed correlation threshold (Z ≥ 0.4). Regional global connectivity scores were used as predictive features in random forest regression (RFR) models to predict changes in outcome measures HDRS-17, HDRS-6, CMA, SoD, and insomnia. All RFR models were trained and validated by repeated 10-fold cross-validation with a nested grid search for parameter optimization. The performance of the models was evaluated as a function of the coefficient of determination (ie, the proportion of explained variance) in the out-of-sample test data. The significance of fit of each model was assessed using permutation tests (B = 1,000 permutations) and multiple comparisons were fitted to the set of all outcome measures with a Bonferroni correction, yielding a critical value of 0.05./5 = 0.01.

Results:The average coefficient of determination (ie, the fraction of explained variance) in predicting the change in the CMA dimension was significantly greater than zero (R^2 =0.19, q=0.005) and was significantly greater than the total HDRS value -17 (R^2 = -0.07). Increased global connectivity of a right somatomotor (SMN) network split, a right dorsal prefrontal cortex split of the default mode network (DMN), and a posterior cingulate/right precuneus DMN split predicted greater symptom reduction. of connectivity predicted rTMS-reduced CMA symptoms ahead. Changes across other HDRS subscales were not predicted using probability levels (all q > 0.05).

Conclusions:Our results support that global pretreatment connectivity of DMN, SMN, and DATTN components predicts dimensional antidepressant response to rTMS. We previously reported DMN connectivity as a predictor of antidepressant response to other pharmacological and behavioral treatments. Interestingly, changes in core mood symptoms (depressed mood, interests, psychomotor retardation, and weight loss) were more accurately predicted than those in the somatic symptom or sleep disturbance groups. These results are consistent with related work showing better prediction of treatment outcomes using latent dimensional outcomes in ketamine and electroconvulsive therapy. Future work will try to replicate these results in a larger sample.

Key words:Repetitive transcranial magnetic stimulation, depression, resting state functional connectivity, machine learning, symptom dimensions

Disclosure:Nothing to disclose.

Joseph Taylor*, Summer Frandsen, Amit Anand, Faith Gunning, David Silbersweig, Katherine Burdick, Amy Brodtmann, Maurizio Corbetta, Gonzalo Cotovio, Natalia Egorova, Sophia Gozzi, Jordan Grafman, Andrew Naidech, Albino Oliveira-Maia, Thanh Phan, Joel Voss , Michael Fox, Shan Siddiqui

Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, Estados Unidos

Background:Patients with bipolar disorder need better treatments. Transcranial magnetic stimulation (TMS) looks promising, but the ideal brain regions for stimulation are unknown. In this study, we derived a map causally associated with mood valence based on the functional connectivity of brain lesions causing mania versus depression.

Methods:We combined seven independent injury datasets for mania and depression into a single model. First, we estimated the connectivity of each lesion site using a normative connectome (n = 1000). Second, we constructed a mood valence map from the different functional connectivity patterns of manic versus depressive disorders. Third, we used permutation tests to determine whether the mean absolute voxel value in the mood valence map was stronger than chance (10,000 permutations). Fourth, we evaluated the specificity of the mood valence map with control lesions not associated with mood disorders. Finally, we tested whether the mean coordinates of common TMS targets (ie, 5 cm bilateral, anti-subgenual, dorsomedial) were preferentially associated with the mood valence map.

Results:Mania is more associated with lesions functionally linked to the right prefrontal cortex and depression is more associated with lesions functionally linked to the left prefrontal cortex. This mood valence map was stronger than expected by chance (p < 0.05) and did not change when multiple control lesions were added to the model (spatial correlation r > 0.99). The left anti-subgenual EMT target was preferentially associated with the negative valence map (p < 0.01) and the right dorsomedial prefrontal cortex was preferentially associated with the positive valence map (p < 0.005).

Conclusions:Mood valence shows left-right frontal lobe asymmetry consistent with existing literature. However, the topography of this asymmetry may guide optimization of TMS treatment goals for bipolar depression versus mania. Future analyzes will look for a potential treatment target that is functionally associated with manic and depressive disorders that may be relevant for mood stabilization.

Key words:Bipolar Disorder, Brain Networks, Injuries, TMS Orientation, Human Connectome

Disclosure:Nothing to disclose.

Michael Henry*, Tracy Barbour, Kristen Ellard, James Luccarelli, Isabella Conner, Amanda Yang, Joan Camprodon

Massachusetts General Hospital, Boston, Massachusetts, USA

Background:The cognitive side effects of electroconvulsive therapy (ECT) have long raised concerns that it damages the brain. Instead, structural imaging studies have found that brain regions that exhibit plasticity show an increase in tissue volume after an ECT regimen. Recently, algorithms based on machine learning have been developed that use regional brain volumes to estimate the physiological age of a person's brain. Our hypothesis is that the increase in volume observed after ECT in depressed people would be sufficient to decrease the brain age calculated by the BrainAgeR machine learning algorithm. Below we present the results of this pilot study.

Methods:Structural magnetic resonance imaging (MRI) images of 44 subjects with major depressive disorder (MDD) who underwent imaging in other studies of ECT-induced image changes were evaluated for inclusion in this analysis. It was found that 37 subjects aged between 19 and 65, 20 males, had completed a pre- and post-treatment scan suitable for analysis. Depression rating scales that were prospectively collected included the Rapid Depressive Symptoms Inventory (QIDS) and the 28-item Hamilton Depression Rating Scale (HAMD-28). Physiological brain age was estimated for each scan using the BrainAgeR algorithm. Since we had hypothesized a priori that the calculated brain age would decrease, the results were analyzed using a one-tailed paired t-test. Due to the exploratory nature of this study, the results were not corrected for multiple comparisons.

Results:There was a significant decrease in estimated physiological brain age among participants after one cycle of ECT (mean change = -0.79 years, p = 0.037). When stratified by clinical response, the within-group change in responders and non-responders did not reach significance. When stratified by senders versus non-senders for QIDS and HAMD-28, the group of non-senders showed a significant decrease in estimated age (QIDS: mean change = -0.99 years, p = 0.018; HAMD-28: mean change = - 0.95 years, p = 0.033), while senders did not.

Conclusions:These data suggest that the BrainAgeR physiological brain age algorithm is sensitive enough to detect the effects of acute treatment for depression. Furthermore, according to our hypothesis, the mean physiological age calculated after ECT decreased in a cohort of depressed individuals. In the analysis of clinical response, non-remitting patients showed a statistically significant decrease in estimated age, while remitting patients did not. Given the small sample size and preliminary nature of these results, replication in a larger study sample is warranted.

Key words:Brain age, electroconvulsive therapy, MRI

Disclosure:Roche Pharma: Employee (spouse)

Erica Baller*, Matthew Cieslak, Timothy Robert-Fitzgerald, Sydney Covitz, Melissa Martin, Matthew Schindler, Amit Bar-Or, Ameena Elahi, Michael Fox, Abigail Manning, Clyde Markowitz, Nebojsa Mirkovic, Christopher Perrone, Victoria Rautman, Donovan Reid, Guy Schultz, Shan Siddiqi, Sunil Thomas, John Detre, Russel Shinohara, Theodore Satterthwaite

University of Pennsylvania, Philadelphia, Pennsylvania, USA

Background:Multiple sclerosis (MS) is an immune-mediated neurological disease that affects one million people in the United States, with up to 50% of patients experiencing lifelong depression. However, the mechanisms of depression in MS remain poorly understood. Previous research using injury network mapping has shown that depression-associated stroke interrupts a reproducible depression network. However, these methods have not been used to study how white matter lesions (WML) are related to depression in MS. This study aims to define in a retrospective sample how depression in adults with MS is related to the location and burden of white matter (WML) lesions.

Methods:Participants with MS were identified from electronic medical records. Depressed individuals (DI) included individuals with evidence of depression as defined by an ICD-10 diagnosis of depression (F32-F34.*), a prescription for antidepressants, or a positive screening test via PHQ2/9 (n = 232, age (SD) = 49 (12), % female = 86). Non-depressed comparators (NDCs) matched by age and sex included individuals without a previous diagnosis of depression, on psychiatric medication, and asymptomatic in PHQ2/9 (n=148, age (SD)=47 (13); %female=79) . Structural MRI was performed as part of routine care in the 3Q using a research-quality protocol. The WMLs were automatically segmented using the cross-modal segmentation analysis algorithm method and designed onto a standard template. Seventy-seven white matter tracts (WMT) were evaluated. The WMT volume crossing each lesion was calculated by optimized filtering in DSI Studio. Total lesion volume was also calculated independently of route and compared between diagnostic groups. The effects of age and diagnosis were evaluated using general linear models and t-tests. We also evaluated the accumulation of effects in a depression network previously described by Siddiqi et al., 2021.

Results:Streamline filtering recapitulated previously known patterns of MS disease with high proportions of streamlines affected in the optic rays, inferior fronto-occipital tracts, medial longitudinal tracts, and corticopontine tracts. Older age was associated with a higher burden of disease in 54/87 WMT (PFDR < 0.05). The total lesion volume did not differ significantly between the two groups (P = 0.07, NS). However, when simplified filtering was used, IDs had a higher average disease burden across all WMTs (P < 0.05, Cohen's d = 0.17), reflecting a higher disease burden within the network of depression.

Conclusions:We present a new approach to calculate the relationship between WML and depression burden. We show that the total burden of lesions does not differ between diagnostic groups, regardless of location. Instead, when considering burden of disease in intersecting lesions, we show that DIs have a higher overall burden of disease compared to NDCs, due to the greater burden of disease in the fibers that connect areas of the depression network. Future work mapping the network of white matter lesions in MS may also improve our understanding of the mechanisms of depression more broadly.

Key words:Depression, multiple sclerosis, electronic medical records, brain MRI

Disclosure:Nothing to disclose.

Emily Cambre, Elena Christenfeld, Gabriella Sahyoun, Jonathan Javitch, Sarah Canetta*

Columbia University, New York, New York, United States

Background:Reward processing deficits, commonly referred to as anhedonia, are a hallmark of several psychiatric disorders. In the context of depression, anhedonia is one of the two main symptoms required for diagnosis and often predicts more serious consequences. Although selective serotonin reuptake inhibitors (SSRIs) are the first-line treatment for depression, they are ineffective for many people and, in certain cases, can even make symptoms worse, including anhedonia. As such, there is a clear gap in our understanding of how antidepressants affect reward processing and why they can vary in effectiveness from person to person.

Methods:Male and female pups were injected with FLX (10 mg/kg, i.p.) or saline in a C57BL/6J (C57) background. Motivation and hedonic cognition were measured in adult PN FLX or vehicle-exposed mice (PN VEH) using a progressive ratio (PR) and a lickometer task, respectively. During the PR test, the mice were food restricted to 90% of their initial weight and, during the lickometer test, the mice were kept ad libitum in citric acid water and food was withheld for 12 hours before the test. Cages of co-housed PN FLX and PN VEH mice were then randomized to receive either chronic FLX or vehicle (water) control as adults. FLX (18 mg/kg) was administered via the drinking water for three weeks and then continuously during behavioral testing. A 2-week washout period followed completion of post-FLX behavioral testing prior to initiating TIA administration. Mice that received FLX previously received TIA and mice that received the control were unaffected. A solution of 30 mg/kg TIA NaCl dissolved in sterile 0.9% saline or saline as a control was injected intraperitoneally twice a day for 14 days. TIA injections continued during the behavioral test.

Results:We found that, as adults, PN FLX animals have reduced motivation to seek rewards, which is manifested by a decrease in the total number of keystrokes (Mann-Whitney, p=0.0017, n=31 PN VEH, 29 PN FLX ). , p=0.0011, n=31 VEH PN, 29 FLX PN), breakpoint (Mann-Whitney, p=0.0018, n=31 VEH PN, 29 FLX PN) and rewards retrieved (t-test, p = 0.0475, n = 31 PN VEH, 29 PN FLX). These mice also have reduced latency to approach the lever and start pushing (Mann-Whitney, p=0.0005, n=31 PN VEH, 29 PN FLX), which may reflect a reduced expectation of reward. Surprisingly, there was no difference in the frequency with which PN FLX and PN VEH mice licked freely available treats in the lickometer test (Mann-Whitney, p = 0.9796, n = 31 PN VEH, 29 PN FLX), suggesting that no there were changes in hedonic perception. Interestingly, we found that administering FLX to adults did not change any of these variables in PN-FLX mice. In contrast, TIA administration in adults increased reward expectancy (Mann-Whitney, p < 0.0001, n = 14 PN FLX-SAL, 15 PN FLX-TIA) but did not consistently change variables related to reward. motivation, including total pressure (Mann-Whitney , p = 0.1456, n = 14 PN FLX-SAL, 15 PN FLX-TIA), session time (t test, p = 0.8056, n = 14 PN FLX -SAL, 15 FLX-TIA PN), breakpoint (Mann-Whitney, p=0.1486, n=14 FLX-SAL PN, 15 FLX-TIA PN) and rewards retrieved (t-test, p=0.8641 , n=14 FLX-SAL PN, 15 PN FLX-TIA).

Conclusions:Our results confirm previous work showing that early exposure to FLX in mice during a period of brain development that occurs during the third trimester in humans results in adult animals showing decreased motivation later in life. We extend this phenotype to show that these effects also involve reward anticipation, while reward learning and hedonic cognition remain intact. Our results also demonstrate that these deficits in motivation and reward expectancy in PN FLX animals are resistant to subsequent FLX administration in adulthood. In contrast, the atypical antidepressant TIA reinforces reward expectancy, although motivation remains unchanged. Taken together, these results suggest that PN-FLX mice may represent a model for SSRI-resistant affective-behavioral changes and that TIA is a promising alternative treatment to SSRIs for people with suspected early intrauterine exposure to SSRIs, SSRIs, and, more generally, a subset may be people with SSRI-resistant depression.

Key words:Reward processing, SSRIs, tianeptine

Disclosure:Nothing to disclose.

Kathryn Ridout*, Mubarika Alavi, Samuel Ridout, Constance Weisner, Esti Iturralde

The Permanent Medical Group, Santa Rosa, California, USA

Background:Major depression (MDD) is a chronic relapsing illness that affects 20.6%1 of the US population, causes significant disability and costs $326.2 billion annually. The patient's risk of new depressive episodes increases from 50% to 90% after the first episode compared with the third episode. Incomplete response to depressive episode treatment is the strongest predictor of relapse and recurrence of depression and increases the likelihood of lost work productivity and disability. Therefore, improving treatment response during the first clinical presentation of a depressive episode in a patient would have the greatest impact on reducing the prevalence, chronicity, and associated disability of depressive disorders. There is evidence that response to treatment of MDD improves with early detection, intervention, and appropriate treatment. However, response to treatment varies between patients and, to date, there are no tools to predict which patients will respond to treatment. This study aimed to examine clinical predictors of response to depression treatment at baseline and at the end of treatment.

Methods:Retrospective observational study in a large integrated health system. Inclusion criteria for participants include age ≥ 18 years, Patient Health Questionnaire 9 score ≥ 5, and seeking outpatient treatment for depression between 3/2020 and 12/2021. Exclusion criteria include acute suicide risk, diagnosis of bipolar disorder, psychosis, dementia, or substance use, current or home palliative care, residency in a skilled nursing facility, or assisted living, or non-insurance membership. Study variables were extracted from electronic medical records 6 weeks and 6 months after initiation of depression treatment. Predictors of depression treatment response were selected based on previous literature. Based on previous literature and our sample size, we estimated the power to detect small effect sizes (f2 of 0.02).

Results:Of the 27,858 patients, 68% were female, 48% white, 19% Hispanic, 14% Asian, 8% black, and 11% other races. Most patients were aged 18 to 39 years (61%), followed by 40 to 59 (27%), 60 to 69 (8%) and 70 years or older (4%); The neighborhood deprivation rate was evenly distributed across categories (23% to 26%). Most patients had a Charleson Comorbidity Index of 0 (84%) and a body mass index ≤ 24.9 (22%). The initial average of the PHQ-9 was 10.7 ± 3.9; The mean waiting time for the first treatment appointment was 2.4 ± 5.2 days. Most patients had not had outpatient psychiatric treatment (63%) or antidepressant therapy (79%) in the last year. Significant predictors of EHR at both time points included baseline PHQ-9; previous psychiatric referral; referral of the patient to psychiatry; Outpatient psychiatric counseling for an illness other than depression; previous antidepressants for disorders other than depression; Genre; Years; and BMI (P < 0.0001 for all). EHR predictors that differed by time point included race (lowest 6-month treatment response for LatinX populations; p<0.0001); Charlson comorbidity index (lower response at 6 months with higher CHF; p<0.0001); Neighborhood Deprivation Index (lowest response at 6 weeks for highest deprivation; p < 0.0001); and initiation of antidepressants during treatment for depression (greater response at 6 months with antidepressant; p < .0001).

Conclusions:Although many clinical variables predicted treatment outcomes for depression both at baseline and at the end of treatment, some variables appeared to differentiate response to treatment at each time point. This study forms the basis for future work examining the use of treatment outcome predictors in prospective treatment decision making.

Key words:Treatment outcome prediction, personalized medicine, depression treatment response

Disclosure:Nothing to disclose.

Jake Stenzel*, Tim Bigdeli, Michele Pato, Carlos Pato, Ayman Fanous

University of Arizona-Phoenix School of Medicine, Phoenix, Arizona, USA

Background:Melancholic features, as the main features of a depressive episode in both major depressive disorder and bipolar I disorder (BD-I), are characterized by depressive episodes with pronounced psychomotor disturbances, anhedonia, weight loss, and guilt, as in diagnosis and Statistics Defined Manual of Mental Disorders, 5th Ed. (DSM-V) (American Psychiatric Association, 2013). Although the validity of melancholia as a diagnostic concept has been widely debated, there is evidence that melancholia differs in the pathophysiology and severity of the disorder. These distinctions include increased hypothalamic-pituitary-adrenal axis dysregulation, pro-inflammatory cytokines IL-5 and IL-4, suicide risk, and psychotic features.

Although most research has focused on melancholia associated with depression, our study examined melancholic traits in a population of patients with BD-I from the Genomic Psychiatry Cohort (GPC) (Pato et al., 2013). The objectives of our study were to identify the prevalence of melancholic traits in a large population of TB-I patients (n = 4025) and to compare clinical and sociodemographic characteristics between melancholic and non-melancholic TB-I patients.

Methods:The GPC pooled a large cohort of patients with schizophrenia, bipolar disorder, and healthy controls from the United States and selected locations abroad. All enrolled participants were asked to complete a screening questionnaire to assess their psychiatric history. Participants registered as probable cases were interviewed by mental health professionals using the Diagnostic Interview for Psychosis and Mood Disorders (DI-PAD). Information on the identification and diagnosis of the study population can be found in a previous publication (Bigdeli et al., 2020).

The diagnosis of psychiatric disorders was obtained from the DI-PAD. Patients were included in this study when they completed all screening documentation and DI-PAD required for each analysis and were diagnosed with Bipolar I Disorder (with or without psychosis). DSM-V criteria for melancholic traits were assessed using the DI-PAD and screening questionnaire. Sociodemographic factors and disease severity were derived from the DI-PAD and screening questionnaire.

Results:Participants with a diagnosis of BD-I who completed the DI-PAD and the assessment questionnaire for all measured variables scored N out of 4025). 74.04% (n = 2980) met the criteria for melancholia. Compared to non-melancholic TB-I, melancholic TB-I was more common in females (77.05% vs. 70.52%, OR=1.40; p<0.0001). Family history of psychiatric disorders was associated with melancholic versus non-melancholic BD-I (67.15% vs. 61.05%, OR =1.30; p<0.001). Furthermore, melancholic TB-I was significantly associated with suicidal ideation lasting at least one week (79.73% vs. 60.86%, OR =2.55; p<0.0001) and suicidal ideation lasting more than one month (69.62% vs. 23.12%, OR). = 7.62; p < 0.0001) compared to non-melancholic BD-I. No significant association was found with the presence of psychosis, nicotine use (defined as smoking more than 100 cigarettes in a lifetime), or history of recreational drug use.

Conclusions:Compared with non-melancholic TB-I, patients with melancholic TB-I tended to be female and had a family history of psychiatric disorders. A marked increase in suicidal ideation lasting longer than one week and longer than one month has also been observed in melancholic patients with BD-I. This observation is consistent with previous studies of melancholic traits in major depressive disorder (Dold et al., 2021; Tondo et al., 2020). Our study was based on DSM-V criteria to determine melancholic traits, while alternative instruments may have resulted in different prevalences. Further investigation of comorbidities and GWAS and NGS data is planned and may provide more information on melancholic features in BD-I.

Key words:Bipolar I Disorder, Psychiatric Disorders, DSM-5, Clinical Psychiatry

Disclosure:Nothing to disclose.

Rhiana Simon, Joshua Yee, Koichi Hashikawa, Garret Stuber, Larry Zweifel, Marta Soden*

University of Washington, Seattle, Washington, USA

Background:The ventral tegmental area (VTA) harbors a heterogeneous population of dopaminergic neurons, as well as significant populations of glutamatergic and GABAergic cells. The VTA receives input from more than two dozen brain regions. Previously, we found that specific inputs innervate VTA subregions differently, and stimulation of selected inputs leads to variable behavioral outcomes and different spatial patterns of cell activation, as measured by Fos protein expression. This implies that different subsets of VTA neurons are activated by different inputs to drive different behavioral modalities, but the specific genetic identity of these activated neurons is unknown.

Methods:To answer this question, we used Cre-dependent viral channelhodopsin (ChR2) expression to stimulate three different VTA inputs in the mouse: GABAergic inputs from the lateral hypothalamus (LH), GABAergic inputs from the nucleus accumbens (NAc), and glutamatergic inputs. of the prefrontal cortex (PFC). Male and female Vgat-Cre (Slc32a1) or Vglut1-Cre (Slc17a7) mice were injected with AAV1-FLEX-ChR2-YFP (or AAV1-FLEX-YFP as control) in one of the indicated regions and optical fibers were implanted over the VTA . After stimulation with 20 Hz blue light, we collected tissues and performed single-core RNA sequencing (snRNAseq). We integrated sequence data from all four groups to create a comprehensive analysis of VTA cell types based on differential gene expression and examined immediate early gene expression (IEG) to determine which groups of cells were preferentially activated by stimulation. The spatial expression of a selection of marker genes was validated by multiplex in situ hybridization.

Results:From approximately 40,000 cells sequenced, we identified over 9,000 neurons with high quality gene expression data. These neurons were divided into 3 groups of mainly dopaminergic cells identified by the expression of canonical markers such as Th, Slc6a3 (DAT) and Ddc. We also identified several groups of primarily GABAergic cells, groups of primarily glutamatergic cells, and a significant group expressing a combination of GABAergic, dopaminergic, and glutamatergic markers. These groups showed different patterns of expression of genes crucial to determine physiology and cell connectivity, including ion channels and neurotransmitter and neuropeptide receptors. We confirmed spatially distinct expression patterns of a selection of marker genes using multiplex in situ hybridization and found that all three dopaminergic groups tended to segregate along the lateral to medial axis, consistent with established functional differences between known dopaminergic subpopulations. Stimulating LH-GABA, NAc-GABA, or PFC-glutamate inputs resulted in increased IEG levels compared to control mice. Analysis of the percentage of cells in each group showing IEG expression revealed unique patterns of group activation for each stimulation group compared to control (Fisher's exact test, P<0.05). Remarkably, the dopamine cell cluster activation patterns matched the spatial innervation patterns of each input (ie, only LH-GABA inputs that innervate the lateral VTA induced significant activation in the dopamine cell cluster). We also observed variability in IEG expression in VTA glutamatergic clusters, with NAc-GABA inputs inducing the greatest activation.

Conclusions:This dataset represents a large and comprehensive single nuclear sequencing analysis of mouse VTA. Analysis of differentially expressed genes between identified cell groups provides valuable information about the organization of this critical brain region and the cellular properties and functions of specific neuronal subgroups. We also provide a proof of concept for a novel approach to analyze cell group activation following optogenetic stimulation and demonstrate the differential activation of VTA cell types by different inputs. These results improve our understanding of the architecture of the circuitry that controls inputs to the midbrain dopamine system and the regulation of dopamine-dependent behaviors.

Key words:dopamine, ventral tegmental area (VTA), RNAseq

Disclosure:Nothing to disclose.

Ana Mendes-Silva*, Suyi Shao, Lucas Taniguti, Mikaela Dimick, Clement Zai, James Kennedy, Benjamin Goldstein, Vanessa Gonçalves

Centre for Addiction and Mental Health, Toronto, Canadá

Background:Mitochondria are the main source of energy for neurons and other brain cells and play crucial roles in various neural processes such as neurogenesis, neuroplasticity and neurotransmission. Malfunctioning of these organelles can disrupt critical neural processes that underlie abnormal brain development and cognitive decline in psychosis due to lack of energy and higher concentrations of inflammatory molecules. Several clinical, genetic, and imaging studies suggest that mitochondrial dysfunction plays a critical role in the pathophysiology of bipolar disorder (BD). The present study aimed to characterize mtDNA variants in adolescents diagnosed with BD and to investigate the association between two common mitochondrial DNA (mtDNA) variants and structural changes in the brain.

Methods:Ninety-six Caucasian adolescents (54 BD and 42 healthy controls (HC)) between 13 and 20 years old of both sexes were included. Psychiatric diagnoses were determined based on semi-structured diagnostic interviews. Mitochondrial DNA was extracted from saliva and the MiSeq platform was used to sequence the samples. The mtDNA variants were identified using the mtDNA server pipeline and common variants were selected with a minor allele frequency (MAF) of at least 5%. Mutserve performed a functional analysis to identify potentially harmful mtDNA variants. The MutPred, Selection Score, and Mito tool algorithms assigned to each potentially harmful variant identified through functional analysis were summed to create a pathogenicity score. In addition, the pathogenicity score and individual variants were tested against the phenotypes using logistic regression in R. For a priori determined regions of interest (ROIs) (anterior cingulate cortex), subcortical volumes, cortical thickness, and cortical surface area (ACC and amygdala) were determined, and associations with each mtDNA variant and pathogenicity score were determined using a general linear model tested in SPSS, adjusting for age, sex, and intracranial volume (ICV) as necessary. To account for multiple tests, a Bonferroni-corrected significance level of 0.0125 was applied.

Results:A total of 1382 homoplasmic variants were identified in our sample, of which 67 were common variants (MAF > 0.05). Functional analysis showed that 9 of the 67 common variants were not synonymous and the variants (MT-ND2):m.4917 A>G and (MT-ND1):m.4216 T>C were classified as potentially harmful. Logistic regression analysis showed the association of the mtDNA pathogenicity score and the 4216 T > C variant with BD (OR: 1.57 [95% CI: 1.04, 2.38], p = 0.031; and OR: 1.99 [95% CI: 1.04, 3.81], p = 0.037). Regression analysis, adjusted for sex and age, showed that both the pathogenicity score and the individual variant (MT-ND1):m.4216 T > C were nominally associated with tonsillar volume across the cohort (ß43.07, p0.037, or ß82.78, p0.024). No pathogenicity score effects or individual variants were found for cortical thickness, surface area, or volume in the ACC. None of these associations were significant after adjusting for multiple tests.

Conclusions:Our results indicate that adolescents with TB have a higher presence of the two reported Complex I pathogenic variants m.4917 A > G and m.4216 T > C. In addition, a higher pathogenicity score and the m.4216 T> variant C were found to be associated with increased amygdala volume, which may reflect neuroinflammation caused by mitochondrial dysfunction. More studies in other populations are needed to substantiate these findings.

Key words:Mitochondria, mitochondrial DNA, bipolar disorder, youth, amygdala

Disclosure:Nothing to disclose.

Fernando Goes*, Leonardo Collado-Torres, Peter Zandi, Joel Kleinman, Daniel R. Weinberger, Ran Tao, Daniel Weinberger, Thomas Hyde

Johns Hopkins School of Medicine, Baltimore, Maryland, USA

Background:Major depression (MDD) is the second leading cause of disability worldwide and a major risk factor for suicide. New treatments are urgently needed, but the development of new types of antidepressants has been hampered by a limited understanding of the pathophysiology of MDD. In the current study, we performed the largest and most comprehensive molecular study of MDD in postmortem brain samples.

Methods:We performed expression profiling on a large cohort of postmortem brains with MDD and healthy controls. RNA sequencing was performed using a Ribozero protocol (mean depth 132 million reads) involving a total of 432 male and female anterior cingulate cortex (ACC) and 429 amygdala samples. Differential expression analyzes were performed using Limma Voom, taking into account typical post mortem confounders, including a measure of differential susceptibility to degradation. Control for multiple tests was performed using a false detection rate of 5%.

Results:A total of 630 and 106 genes were differentially expressed in the ACC and amygdala, respectively. The mean fold change was modest (OR ~1.1) and the most differentially expressed gene in both the ACC and the amygdala was FUS, an RNA-binding protein previously implicated in neurodegeneration. Furthermore, using a broad transcriptional association study approach, we found 88 genes meeting the Bonferroni significance level and 309 genes meeting the FDR < 5% significance level in the anterior cingulate and amygdala. Bonferroni-corrected genes include several previously associated with GWAS significance levels (e.g., SORCS3, ZKSCAN7, LIN28B, RMT61A, RANGAP1, FADS1, TMEM258, FNIP2, NRG1, and many others), as well as numerous new genes, such as SIRT1, which are present in a severe MDD GWAS in China and are now finding converging evidence for an association in a sample of European ancestry

Conclusions:Major depression is associated with several hundred differentially expressed genes, consistent with a large polygenic contribution to molecular traits. The definition of the molecular landscape of gene expression in brain regions associated with the pathophysiology of MDD may lead to the identification of new therapeutic targets, especially in relation to risk loci identified in large-scale genetic studies.

Key words:Transcriptoma, human postmortem brain tissue, major depressive disorder (MDD), anterior cingulate cortex (ACC), amygdala

Disclosure:Nothing to disclose.

Mandakh Bekhbat*, Ebrahim Haroon, Sarah Etuk, Jennifer Felger, Andrew Miller, Michael Treadway

Emory University, Atlanta, Georgia, USA

Background:Inflammation and impaired glucose metabolism are two pathways involved in the pathophysiology of anhedonia in major depressive disorder (MDD). These signaling pathways are thought to act synergistically within circulating immune cells, allowing inflammatory activation to change metabolic demands and reprogram cellular energy sources to drive pro-inflammatory activities, including systemic inflammation and its impact on brain processing and rewards. , to contribute to the symptoms of the disease. disease that contributes to anhedonia. We have previously demonstrated relationships between symptoms of anhedonia and a gene expression pattern in whole blood consistent with an increased reliance on glycolysis (as opposed to oxidative phosphorylation [OXPHOS]), a hallmark of metabolic changes in activated cells, but only in patients with MDD. with high inflammation (plasma C-reactive protein [CRP] > 3 mg/L). We also report associations between plasma inflammatory biomarkers and glucose metabolism biomarkers and reduced exertion, a key index of motivational anhedonia, in MDD patients with CRP > 3mg/L undergoing anti-inflammatory exercise. These results suggest that immunometabolic alterations in depressed patients with high levels of inflammation may contribute and serve as intervention targets for anhedonia symptoms. The tumor necrosis factor (TNF)-alpha antagonist, infliximab, was previously found to selectively improve symptoms of anhedonia, including exercise-based motivation, in MDD patients with increased inflammation. Here, we analyzed microarray data from a cohort of MDD patients with severe inflammation before and after a single anti-inflammatory challenge with infliximab versus placebo to discover new immunometabolic signatures for the effect of infliximab on anhedonia.

Methods:N = 42 clinically stable, drug-free, depressed patients aged 21 to 65 years with severe inflammation (CRP > 3 mg/L) were studied before and two weeks after a single infliximab infusion (5 mg/kg body weight ) or placebo. Anhedonia was assessed using the Depressive Symptoms Inventory-Self-Report (IDS-SR) subscale and whole blood gene expression was traced using the Clariom S gene array platform (ThermoFisher) at baseline and week 2 after the infusion. The microarray data were normalized and batch corrected by SST-RMA. A differential expression analysis was performed using linear models on microarray data (Limma) to assess the effects of interaction between treatment and time while controlling for clinical covariates (age, gender, and race). Functional pathway enrichment was queried using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and WikiPathways databases.

Results:At baseline, anhedonia severity was negatively associated with 117 gene probes (R < -0.30, p < 0.01) enriched for mitochondrial complex I of the OXPHOS system pathway (p < 0.05, q < 0.1). Among those receiving infliximab, responders with >50% reduction in anhedonia compared to non-responders had increased baseline expression of 82 gene probes that enriched IL-17 and NF-kappa B signaling pathways (p<0.05 , q<0.1). Longitudinal gene expression and behavioral data were available from fifteen patients treated with infliximab and fourteen patients treated with placebo. Two weeks after a single infliximab infusion, there was a significant decrease in the expression of 44 gene probes enriched for PI3K/AKT/mTOR, as well as in glycolytic and gluconeogenetic pathways (p<0.05, q<0.1). In contrast, only 36 genes significantly changed after placebo, leading to enrichment of broad, non-specific signaling pathways.

Conclusions:Our results indicate that anhedonia in patients with major depressive disorder with high levels of inflammation is associated with altered energy pathways, including lower OXPHOS at baseline, which may reflect a proglycolytic shift characteristic of activated immune cells. Furthermore, increased expression of inflammatory pathways at baseline predicted reduced anhedonia scores after infliximab, consistent with our previous results. Finally, the effects of infliximab included a reduction in glycolysis and upstream mTOR signaling. These results underscore the metabolic reprogramming in circulating immune cells associated with systemic inflammation in MDD, which may lead to the identification of new metabolic and anti-inflammatory targets for the treatment of anhedonia and/or MDD with increased inflammation.

Key words:Immunomodulation, immune metabolism, anhedonia, precision medicine for depression, microarray

Disclosure:Nothing to disclose.

Lisa Brown*, Joseph Stanton, Kanika Barthi, Abdullah Al Maruf, Daniel Mueller, Chad Bousman

Great Scott! Consulting, Brooklyn, New York, USA

Background:Pharmacogenomic testing (PGx) has emerged as an attractive strategy that clinicians can use to inform drug selection and dosing, but the clinical effectiveness of this strategy has been questioned. Here, we attempted to systematically review and meta-analyze prospective controlled clinical trials for an association between PGx testing and remission of depressive symptoms in patients with major depressive disorder (MDD).

Methods:We reviewed PubMed and systematic review bibliographies published up to July 12, 2022. We included prospective controlled clinical trials investigating the association between PGx testing and remission of depressive symptoms in adults, available in English. The study met the 2020 PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) Reporting Guidelines and was registered in PROSPERO (CRD314807). Information extracted included the year of publication of the study, study design, sample size, study eligibility criteria, study duration, participant characteristics (i.e., age, sex, ancestry), measure of remission used, and description of the genes involved in the PGx test performed were included. Two independent reviewers extracted data and a third reviewer identified discrepancies. The risk of bias for each study was assessed and a random effects model was used to estimate the pooled risk ratios. Remission of depressive symptoms was defined as a score ≤ 7 on the Hamilton Rating Scale for Depression-17, ≤ 2 on the Clinical Global Impression Scale, or ≤ 5 on the Patient Health Questionnaire.

Results:Thirteen studies involving 4767 patients were analyzed, including ten randomized controlled trials (RCTs) and three open-label studies. In all included studies, those who received PGx-guided antidepressant therapy (n = 2395) achieved 1.41 (95% CI 1.15-1.74, p = 0.001) greater odds of achieving remission than those who received unguided antidepressant therapy (n =   2372 ). 🇧🇷 🇧🇷 Pooled risk ratios for randomized controlled trials and open-label trials were 1.46 (95% CI 1.13 to 1.88) and 1.26 (95% CI 0.84 to 1.88), respectively.

Conclusions:The PGx test is associated with a modest but significant increase in remission of depressive symptoms in adults with MDD. The heterogeneity in the composition of the PGx test and concurrent prescribing recommendations across studies likely contribute to the uncertainty about the effectiveness of the PGx test in the literature.

Key words:Pharmacogenetics, Depression, Pharmacogenetics

Disclosure:Great Scott Consulting: Founders (Auto), Tempus Labs: Associates (Auto), Myriad Genetics: Stocks/Equities (Auto)

Mark Niciu*, Natalia Schmidt, William Guiler, Amanda Decker, Brian Kinnaird, Kornel Schuebel, Carlos Zárate, David Goldman

University of Iowa Health Care, Iowa City, Iowa, EUA

Background:Major depression (MDD) has an overall lifetime prevalence of approximately 16% and is associated with high morbidity and mortality, including suicide. Standard first-line antidepressants are effective in some but not all patients with MDD, as demonstrated by numerous real-world efficacy studies, including Sequenced Treatment Alternatives to Relief Depression (STAR*D) and the International Study to Predict Optimized Treatment for Depression (I spy). -D). As also illustrated in these studies, first- and second-line antidepressants have monoaminergic mechanisms of action, so it is not surprising that patients with MDD who fail an initial trial are at greater risk of failing subsequent drug trials due to their pharmacodynamic similarities. to fail. 🇧🇷 On the other hand, the N-methyl-D-aspartate receptor antagonist and the glutamate ketamine modulator at subanesthetic doses have a fast-acting antidepressant and antisuicidal action in these patients. The mechanisms of action of ketamine, e.g. B. molecular and cellular responses have been studied in brains of preclinical model organisms and peripheral human tissues, but have not yet been described in tissues similar to the human central nervous system. In this study, we report whole and individual cell transcriptomic data from cultures of human cortex-like spheroids/organoids derived from stem cells exposed to low doses of ketamine and its bioactive metabolites in vitro.

Methods:Whole blood samples were collected from subjects participating in clinical trials at the Division of Pathophysiology and Experimental Therapeutics of the National Institutes of Health for laboratory-created stem cell lines. Next, peripheral blood mononuclear cells (PBMCs) were isolated and transformed into human-induced pluripotent stem cells (hiPSCs) by Sendai virus-mediated transient transfection of plasmids containing Yamanaka factors, e.g. B. Klf4, c-Myc, Out-3/4 and Sox2, reprogrammed. 🇧🇷 Other validated stem cell lines, e.g. B. PENN025i-71-58 and STAN062i-164-2 were purchased from WiCell (Madison, WI, USA). Human pluripotent stem cells (hPSCs) were then differentiated into human cortical spheroids (hCS) following methods developed by Sergiu Pasca's laboratory (Stanford University, Palo Alto, CA, USA). After reaching maturity (>40 days in vitro), hCS were challenged with low doses of ketamine and other bioactive ketamine metabolites, e.g. B. 2 R,6R-hydroxynorketamine (HNK). Briefly, we followed either the next-generation Ion Torrent RNA sequencing pipeline (ThermoFisher Scientific, Waltham, MA, USA) or 10x Genomics Chromium Single Cell System Seq analysis (10x Genomics, Pleasanton, CA, USA).

Results:In whole cell transcriptomics, no genes were up-regulated ≥1.5-fold by short exposure (1 h) to low doses of racemic ketamine (10 mcM) compared to vehicle control. 10 genes were ≥1.5x down-regulated (p<0.05) but did not survive false detection rate (FDR) correction. In response to (2R,6R)-hydroxynorketamine (1 h, 5 mcM), 13 genes were up-regulated ≥1.5x, with FDR corrected for p≤0.05, and 4 genes were down-regulated ≥1.5x, where the FDR was corrected to p ≤ 0.05. Analyzes of signaling pathways revealed 3 clusters for upregulated genes: axon guidance (mediated by microtubules), transcriptional regulation (histones) and translational regulation (ribosomal proteins). In subsequent experiments, hCS were briefly exposed to multiple low doses of racemic ketamine. Single-cell RNA-Seq was performed in collaboration with the Division of Genomics at the Iowa Institute of Human Genetics. At the time of abstract submission, these data are being processed with an advance presentation for the first time at the 2022 Annual Meeting of the American College of Neuropsychopharmacology (Phoenix, AZ, United States)

Conclusions:We identified several genes/clusters that were altered by low doses of ketamine and/or its bioactive metabolites in cultures of hPSC-derived cortical organoids. In whole cell transcriptome analyses, 2R,6R-hydroxynorketamine, which is believed to have non-NMDA receptor antagonistic properties [Zanos et al. (2016) Nature 533(7604):481-6, PMID: 27144355] tightly regulated several genes involved in cytoskeletal reorganization, e.g. Statmin-like 2 (STMN2), tubulin beta-2B, and microtubule-associated proteins 1B and 2. Given the known effects of low-dose ketamine on synaptic plasticity, it seems logical that cytoskeletal genes would appear to be rapidly regulated. An important future direction is to determine whether these transcriptional changes correlate with antidepressant efficacy. This can be assessed by stratifying into 'textbook limits of efficacy', eg B. hCS derived from ketamine nonresponders and ketamine remitters in response to a brief low-dose incubation with racemic ketamine and/or its bioactive metabolites.

Key words:Transcriptomics, ketamine, (2 R,6 R)-hydroxynorketamine, stem cells, brain organoids

Disclosure:Johnson und Johnson-Janssen: Contract Investigation (auto)

Yuliya Nikolova*, Amy Miles, Fernanda Dos Santos

Centre for Addiction and Mental Health, Toronto, Canadá

Background:Transcriptomic studies in postmortem human brain tissue have begun to shed light on the molecular mechanisms involved in major depressive disorder (MDD). However, it is unclear how these transcriptomic changes might affect brain structure or function in vivo. We recently leveraged shared cis-eQTL single nucleotide polymorphisms (SNPs) to construct a transcriptome-based polygenic risk score (tPRS) reflecting developmental shifts toward depression-like corticolimbic gene expression patterns based on 76 expressed genes. differentially in MDD. We identified distinct gender-specific neurofunctional and neurostructural signatures associated with an increased risk of tPRS and MDD in young adults, independent of traditional MDD-PRS effects emerging from genome-wide association studies (GWAS). To elucidate the impact of tPRS on neurodevelopment and provide insight into when these risk phenotypes may first appear, we set out to analyze an expanded version of tPRS, covering 332 differentially expressed genes in MDD, for individual differences in brain structure. and depressive symptoms in participating children. in the Adolescent Brain Cognitive Development (ABCD) study.

Methods:This study used tabular neuroimaging data collected at baseline from 5124 non-Hispanic white participants in the ABCD study (2737 men, 2387 women; age 9.9 ± 0.6 years (range: 8.9 - 11.0)). We used the MetaXcan tool and the CommonMind Consortium reference transcriptome to impute relative gene expression in the dorsolateral prefrontal cortex (dlPFC) at the individual level. Individual SNP contributions were determined based on the weights in a tissue-specific elastic network predictive model (DLPFC_newMetax.db). Using this model, we were able to assign 9,347 genes, including 332 of the 566 genes previously identified in a case-control meta-analysis of post-mortem brain corticolimbic transcriptomes datasets (“metaA-MDD genes”). The tPRS was calculated as the sum of the imputed expression values ​​of the 332 imputed genes, each weighted with the direction of action in the original post mortem meta-analysis. Separate mixed-effects linear models were used to calculate the main effects of tPRS and tPRS interaction by gender on volume in each subcortical segmentation (n = 14) and cortical thickness and surface area in each cortical partition based on the Desikan atlas- Killiany (n=68). An FDR correction was applied to each analysis to account for testing in multiple regions. In each case, tPRS, gender, age, estimated total intracranial volume (eTIV, not included in cortical thickness analyses), and 10 genetic components were modeled as fixed effects, while location was modeled as a random effect. Depressive symptoms were indexed using the Parent-Reported Child Behavior Checklist (CBCL) t-score for depressive syndromes.

Results:We identified a significant tPRS-dependent interaction effect on volume in the right hippocampus (HPC.R: t = -3.087, pFDR = 0.028) and in the right pallidum (PAL.R: t = -2.808, pFDR = 0.035). Higher tPRS was associated with lower volumes of both structures in females (HPC.R: t = -3.058, pFDR = 0.002; PAL.R: t = -3.112, pFDR = 0.002), but not in males (HPC.R : t = 1.379, pFDR = 0.227; PAL.R: t = 1.208, pFDR = 0.227). Higher tPRS was also associated with greater cortical thickness in the left posterior cingulate cortex when the entire sample was tested (t=3.739, pFDR<0.001). No other neurostructural effects occurred. Right lower hippocampus and pallidum volume also showed trend-level associations with higher depressive symptoms in the female subsample (HPC.R: t = -1.942, p = 0.052, pFDR = 0.052; PAL.R: t = -2.121, p = 0.034, pFDR = 0.052), with right pale volume also being a significant mediator of an indirect effect of tPRS on increased depressive symptoms (PAL.R, p = 0.016). In contrast, posterior cingulate cortex thickness was not associated with depressive symptoms when tested across the sample (t = 0.009, p = 0.993). The significance of all effects remained unchanged when a more conventional GWAS-based measure of MDD PRS was included as an additional covariate.

Conclusions:Our results suggest that genetic variants associated with changes towards a depression-like corticolimbic transcriptome may have a sex-specific neurodevelopmental signature affecting the morphology of corticolimbic regions, which may indirectly increase the risk of depression, particularly in female participants. Future studies will examine the effects of tPRS on brain maturation and change in depressive symptoms during adolescence to identify risk pathways amenable to early prevention efforts.

Key words:Depression, polygenic scores, MRI, ABCD study, brain structure

Disclosure:Nothing to disclose.

Angelos Halaris*, María Filip, Piotr Galecki

Loyola University School of Medicine, Maywood, Illinois, USA

Background:Sirtuins are proteins found in all aerobic organisms. They are enzymes that regulate important biological functions and are involved in several signaling pathways. There are seven known sirtuins in humans (Sirt1-Sirt7). They are present in all organisms including bacteria. Sirtuins have been implicated in caloric restriction, aging, metabolism, cancer, transcription silencing, chromosomal stability, cell differentiation, stress response, inflammation, apoptosis, DNA repair, and prevention of age-related eye diseases. Sirt1 is involved in gene silencing, cell cycle, lipid and glucose metabolism, and cellular oxidative stress. A genetic study has attracted a lot of attention for its association with depression and found Sirt1 to be a potential genetic target. The CONVERGE Study Cconsortium (Commonwealth University of China, Oxford and Virginia Experimental Research on Genetic Epidemiology) identified two loci that contributed to the risk of MDD on chromosome 10: one is close to the Sirt1 gene (P52.53310210) and the other is within of one of the introns of the LHPP gene (P56.45310212). A case-control study in Japan showed that an SNP (rs10997875) in the Sirt1 gene may play a role in the pathophysiology of MDD. A link between the Sirt1 gene (rs3758391) and depressive disorders has also been found. Furthermore, Sirt1 expression in peripheral blood has been shown to be significantly lower in people with depression than in healthy individuals. Sirt1 expression is significantly reduced in the blood of MDD patients compared to controls and MDD patients in remission. Given the relative scarcity of studies on depressive disorders, we carried out the present study.

Methods:Seventy-two newly admitted hospitalized patients who met diagnostic criteria for recurrent major depressive disorder (MDD) and inclusion/exclusion criteria were included in the study after signing an informed consent form. A comparison group consisted of 74 healthy volunteers with a negative history of any mental disorder. Complete clinical and laboratory data on these individuals were retrieved from the departmental database. The following data were collected: sirtuin 2-7 mRNA expression levels, results of 21 cognitive assessment tests, clinical parameters describing the patient's depressive disorder. Data were analyzed to identify possible differences in sirtuin 2-7 mRNA expression levels between the patient group and healthy controls, correlations between sirtuin 2-7 mRNA expression levels, and cognitive assessment outcomes in the group. of MDD patients, correlation between sirtuin 2-7 mRNA expression levels, and clinical data describing disease progression in the patient population. The study was approved by the Bioethics Committee nº RNN/137/17/KE and nº RNN/303/18/KE and the collection of biological research material was approved by the approved Bioethics Committee nº RNN/566/08/KB.

Specific study objectives included: 1. To determine whether sirtuin 2-7 gene expression differed between patients and healthy controls. 2. To determine whether there were correlations between sirtuin 2-7 gene expression levels and the severity of cognitive impairment in these patients. 3. Determine if there are correlations between the gene expression levels of these genes and the clinical variables of these patients.

Results:Sirtuins 2-7 gene expression levels differed statistically significantly between the two study groups. Expression levels of the sirtuin 2, sirtuin 3, sirtuin 4, sirtuin 5 and sirtuin 7 genes were significantly higher in patients compared to healthy controls. In contrast, the sirtuin-6 gene expression level was statistically significantly higher in the healthy controls compared to the patient group. There were statistically significant correlations between sirtuin 4 gene expression level and cognitive function on the Stroop B scale for time and sirtuin 7 gene expression level and cognitive function on the California Language Learning Test CVLT2 and raw SIET scale. Finally, there were statistically significant correlations between the gene expression level of two sirtuins, 3 and 6, and the Hamilton depression score on the day of admission.

Conclusions:Expression of genes encoding sirtuins 2-7 in patients with relapsed MDD differs significantly from expression of these genes in healthy individuals. There were three significant correlations between sirtuin 2–7 gene expression and the severity of cognitive impairment in patients compared to healthy controls. Sirtuin gene expression may be a biomarker of cognitive impairment in this patient population, if confirmed in future studies.

Key words:Major Depression (MDD), Biomarker, Gene, SNP, Sirtuin

Disclosure:Nothing to disclose.

Salahudeen Mirza*, Camila De Carvalho-Lima, Alexandra Del Favero-Campbell, Alexandre Rubinstein, Brenda Cabrera-Mendoza, Consuelo Walss-Bass, Joao Quevedo, Jair Soares, Gabriel Fries

Child Development Institute, University of Minnesota, Minneapolis, Minnesota, USA

Background:Suicide is one of the leading causes of death worldwide and has shown extensive comorbidity and genetic correlation with bipolar disorder (BD). TB patients have a 10 to 30 times greater risk of suicide. DNA (mDNA) methylation patterns involve both genetic and experimental contributions and may be promising biological substrates for suicide attempt (SA) risk. Previous studies have considered mDNA in AS, but appropriate diagnostic reference groups are often lacking to better unravel the pathophysiology of AS and the psychiatric disorder. We performed an extensive association study of AS in BD throughout the epigenome.

Methods:DNA from 79 BD patients with a history of AS (BD/SA) and 84 BD patients without a history of AS (BD/non-SA) was isolated from the buffy coat fraction of whole blood. 500 ng of DNA was converted with bisulfite and hybridized with the Illumina Infinium EPIC BeadChip, which interrogates methylation at more than 850,000 sites of cytosine before guanine (CpG). Analyzes accounted for genome-wide methylation differences between BD/SA and BD/non-SA. False detection rate significant (q <0.05) (FDR) differentially methylated positions (DMPs) were detected using linear models with the Limma package in R, and significant (Šidák p <0.05) differentially methylated regions (DMRs). ) The Šidák corrections were discovered using comb-p within the ENmix package in R. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to assess the predictive ability of a binomial generalized linear model , which predicts BD/SA from beta values ​​for significant FDR DMPs. Genetic Ontology Pathway Enrichment (GO) Analysis using the DMPs at p<0.001 was performed using the Gometh function in the missMethyl R package. Weighted Gene Cotylation Network Analysis (WGCNA) using the DMPs at p<0, 05 and located at the transcription start sites was performed in the R WGCNA package, and the relationship of modules with BD/SA was evaluated using binomial generalized linear models adjusted for age and sex and subjected to enrichment analysis. GWAS enrichment analysis was performed using a gene pool consisting of DMPs at p<0.05 and summary statistics for current SA-GWAS. Analyzes of Weapons of Mass Destruction and Weapons of Mass Destruction adjusted for age, sex, the first three principal genomic ancestral components, mDNA-based WBC ratio estimates, and mDNA-based estimates of smoking score.

Results:Six significant DMPs for FDR were related to BD/SA, with the leader site closest to the IL8 gene (hypomethylated to BD/SA; logFC = -0.33, pFDR=0.03). The AUC for the ROC curve predicting BD/SA of the six significant FDR-DMPs was 83.5% (CI = 77.4-89.59%). Nine significant DMRs were identified ranging from 3 to 19 CpG sites, with the leading DMR closest to the CLDN9 gene (Šidák p = 7.09 × 10-9). Analysis of GO signaling pathway enrichment by calcium-modulated biological processes implicit in DMP. Six co-methylated modules ranging from 188 to 7237 CpG sites were identified in the WGCNA analysis. All six modules were significantly related to BD/SA, with one module (β=7.15, pFDR=0.004) enriched for genes associated with immune processes in the GO analysis. GWAS enrichment analysis revealed no gene pool enrichment in summary statistics for AS in BD, AS in psychiatric disorders, and AS in the general population.

Conclusions:The results suggest an epigenetic signature associated with AS in BD. These biological factors may be useful to delineate a more severe subset of TB patients prone to suicidal behavior. The DMP and WGCNA analyzes converge on immune system processes, which parallels existing literature documenting peripheral immune dysfunction in suicidal behavior. The divergence between the genetic and epigenetic correlates of suicidal behavior suggests that the risk of suicidal behavior at each of these levels may involve different biological mechanisms. Therefore, the integration of genetic and epigenetic information may provide more clarity in understanding the pathophysiology of suicidal behavior. On both fronts, replication studies are needed to understand the reliability of identified (epi)genetic markers if they are to be included in (preventive) intervention efforts.

Key words:Association studies across the epigenome, suicide attempt, bipolar disorder (BD), peripheral blood marker, DNA methylation

Disclosure:Nothing to disclose.

Gabriel R. Fries*, Salahudeen Mirza, Camila Nayane de Carvalho Lima, Wei Zhang, Giselli Scaini, Amit Srivastava, Zhongming Zhao, Benson Mwangi, Jair C. Soares, João de Quevedo

University of Texas Health Science Center em Houston, Houston, Texas, EUA

Background:Bipolar disorder (BD) is a worldwide psychiatric illness associated with functional limitations and increased risk of suicide. There is an urgent need to identify the biological mechanisms underlying BD to facilitate risk assessment, prevention, and intervention efforts. Epigenetic processes may be one way in which experiential risk and genetic responsibility interact to increase TB risk. In particular, microRNAs (miRNAs) have recently emerged as important candidates in the study of psychiatric disorders because of their dynamic expression and their ability to regulate the expression of many target genes. However, miRNAs taken from the periphery do not directly reflect miRNA expression in the brain. We isolated extracellular vesicles (EVs) from plasma labeled for neural origin to identify a peripheral marker for gene expression in the brain. We then performed differential miRNA expression analysis between BD patients and healthy controls (HCs) to identify miRNAs that may be differentially expressed in the brain of living BD patients (ED).

Methods:This preliminary analysis included 20 TB patients and 20 age- and sex-matched HCs. EVs were isolated from plasma using the ExoQuick® ULTRA EV Isolation Kit (Systems Biosciences) and subjected to further immunoprecipitation for L1 cell adhesion molecule neural adhesion protein (L1CAM), a validated marker for nerve-derived EVs. Total RNA was isolated from nerve-derived EVs using the exoRNeasy Midi kit (Qiagen) and prepared for RNA sequencing on Illumina NextSeq. Sequencing reads were sent to the ERCC-ExceRpt-Small-RNA-seq pipeline (v.4.6.2) with default settings (adapter cut, alignment with miRBase hg38). After the filtering steps, 157 miRNAs remained for differential expression analysis in DESeq2 (v.1.36). The design was adjusted for age (median division) and sex, using the HC as a reference. Correction of the Benjamini-Hochberg False Discovery Rate (FDR) procedure for multiple comparisons. Significant DE miRNAs for FDR were entered into the miEAA 2.0 web tool to identify genetic ontology (GO) processes (miRTarBase, miRWak), disease (MNDR), signaling pathways (KEGG, miRWak) and target gene (miRTarBase). We focused on signaling pathways, processes, and target genes involving the greatest number of FDR-significant ED miRNAs.

Results:Differential expression analysis revealed 27 miRNAs that were significantly differentially expressed in FDR in patients, led by hsa-miR-301a-3p (log2FC = 3.88, pFDR = 1.32 × 10-6). Variance-stabilized expression of hsa-miR-301a-3p graded TB patients with a ROC curve AUC of 70% (CI = 54-86%). At the threshold of FDR importance, 16 miRNAs were up-regulated and 11 miRNAs were down-regulated. GO processes involved included enzyme binding, cell proliferation, neuron projection, and upregulation of protein phosphorylation (miRTarBase); transcriptional upregulation of the RNA polymerase II promoter, extracellular region, blood clotting, and endoplasmic reticulum membrane (miRWak). Diseases included carcinoma, duct, breast; hepatocellular carcinoma; breast cancer; and colon cancer. Signaling pathways included Yersinia infection, regulation of the actin cytoskeleton, synthesis, secretion and action of growth hormone, AGE-RAGE signaling pathway in diabetic complications (KEGG); Cancer, focal adhesion, integrated pathway of pancreatic cancer and angiogenesis (miRWak). Target genes included NUFIP2, PTEN, WASL and MBNL1.

Conclusions:Our preliminary results support an epigenetic biosignature for BD and validate the potential of neurally derived EVs to characterize miRNA expression patterns in BD and other psychiatric disorders. The established relevance of target genes to nervous system function and psychiatric disorders is promising. More research is needed to better understand the functional implications of the observed miRNA changes and their concordance with studies performed on postmortem brain tissue. Particularly given the increased burden of certain diseases in patients with TB, miRNA alterations may be a potential pathway for disease risk, although this hypothesis is tentative. Regardless, the results offer a promising first step towards incorporating brain-specific miRNAs into surveillance and intervention work.

Key words:Bipolar Disorder, MicroRNA, Extracellular Vesicles, Epigenetics

Disclosure:Nothing to disclose.

Alexander Lin*, Katherine Breedlove, Jessica Busler, Eduardo Coello, Huijun Liao, Pamela Mahon, Pamela Mahon

Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, Estados Unidos

Background:Functional MR spectroscopy (fMRS) at 7T provides greater sensitivity and spectral dispersion, allowing detection of dynamic changes in brain metabolite concentrations under specific functional tasks. Recently, fMRS experiments performed at 7 T successfully detected changes in metabolite concentrations. To maximize the sensitivity of these experiments, high system and patient stability (ie, B0 homogeneity, negligible B0 drifts, effective water suppression, low eddy currents, and negligible patient movement) is required. In addition, special processing is required to account for the different external instabilities of the experiment. This work presents a new fMRS methodology to study metabolic alterations associated with emotional processing with increased sensitivity in 7 T. An acquisition protocol was developed for the evaluation of a visual go-no-go task. In addition, a processing pipeline that corrects measurement instabilities is presented.

Methods:Data acquisition: All data were acquired on a 7 T scanner (Terra; Siemens, Erlangen, Germany). Patients were scanned on a 32-channel single-channel receive maincoil with additional dielectric padding to improve B0 heterogeneity. High resolution magnetic resonance images were acquired using fast gradient echo prepared by magnetization with different inversion times (MP2RAGE) with TR = 2.530 ms, TE1 = 1.64 ms, TE2 = 3.5 ms, TE3 = 5.36 ms, TE4 = 7.22 ms, flip = 7 ° captured, FOV = 256 cm, resolution 0.7 × 0.7 × 0.7 mm, acceleration factor 2, for a scan time of 6 minutes. A volume of 20 x 40 x 20 mm3 was acquired with a semi-LASER localization sequence optimized for 7T28 with gradient modulated FOCI pulses to reduce the B1 peak (TE = 28 ms, TR = 5 s, 128 scans, spectral width 6 kHz). Water vapor suppression is interspersed with external volume saturation. The unsuppressed water signal was acquired using 4 mean values ​​for eddy current correction and as an internal reference for metabolite quantification. 768 signal media were acquired over the course of the experiment for a total acquisition time of 24 min.

Visual stimuli and fMRS paradigm: The fMRS paradigm consisted of an affective go/no-go task to assess emotion regulation. Participants were instructed to silently read each word presented and then press a key for words with normal writing (Go test) and suppress that response for words with cursive writing (No-Go test). The stimuli (words) had negative, positive and neutral valence. On-task performance and post-task assessment of stimulus recognition and valence were used to determine participants' adherence to task instructions.

Data Processing and Quantization: The pipeline used for spectra reconstruction was implemented in Python using OpenMRSLab and included the following steps: (1) coil matching, (2) frequency matching with water, (3) phase elimination of zero order, (4) combination of 4 signal averages (sub-blocks) to increase SNR for processing, (5) dehydration in each sub-block using HSVD, (6) frequency matching with NAA, (7) phase dehydration zero order, (8) dynamic temporal signal filtering (eg, sliding window averaging, Fourier thresholding), and (9) combining subblocks to obtain the desired temporal resolution to conform to the paradigm. Frequency/phase corrections eliminated distortions caused by external effects that affect the measurement, such as B. Drift B0, eddy currents, temperature or the BOLD effect. The reconstructed spectra corresponding to consecutive time points were fitted using LCModel with a simulated base set.

Results:Analysis of the fMRS auditory data revealed the presence of the BOLD signal by subtracting each STIM block from its closest REST block. Fluctuations in metabolite concentrations were observed and improved by dynamic filtering. Concentrations of quantified metabolites processed by the different methods are shown superimposed on the visual paradigm. The visual experiment served to validate the methodology, as it was able to reproduce previously published experiments.

Conclusions:This is a promising development for the application of functional MRS in the study of mood disorders such as bipolar disorder. Impaired performance in neural activation and neurometabolite levels has been correlated with these continuous tasks in patients with bipolar disorder. Therefore, the ability to measure dysfunctions in glutamatergic systems, which may indicate a network dysfunction seen in mood disorders, is a promising application of functional MRE.

Key words:Functional MRI Spectroscopy, Emotion Regulation, Ultra High Field MRI, GoNoGo

Disclosure:Agios Pharmaceuticals, Biomarin Pharmaceuticals, Design Therapeutics, Moncton MRI: Berater (auto), BrainSpec, Inc: Fundador (auto)

Samantha Hu, Aniruddha Shekara, Maxwell Tallman, Rodrigo Patino, Thomas Blom, Jeffrey Welge, Jeffrey Strawn, Kaitlyn Bruns, David Fleck, Manpreet Singh, Caleb Adler*, Melissa DelBello

University of Cincinnati School of Medicine, Cincinnati, Ohio, USA

Background:Antidepressants are the first-line treatment for young people with anxiety and/or depression; However, its use may carry a significant risk of psychiatric adverse events (eg, increased irritability, aggressiveness, impulsivity, psychosis) associated with increased emotional arousal (EH). This can be especially important in people with a family history of bipolar disorder (BD). Previous studies have shown that selective serotonin reuptake inhibitors (SSRIs) can alter fronto-limbic neural pathways, which are critical for emotion regulation; however, the neural mechanisms of HD remain largely unknown. We used functional neuroimaging to study youth at familial risk of BD treated for anxiety and/or depression to determine whether changes in emotion-associated frontolimbic networks predict dysfunctional emotional arousal.

Methods:75 adolescents with a family history of BD and current anxiety or depressive disorder were recruited from the University of Cincinnati and Stanford University. All participants received escitalopram and 14 young men developed Huntington's disease during the treatment period of up to 16 weeks. All participants completed functional magnetic resonance imaging (Fmri) at baseline. A second scan was performed at the time of HE insertion. Ten young men on escitalopram who were matched for duration of treatment, age, sex and location and who did not develop HD over the 16-week period were also examined for comparison.

Huntington's disease was defined by clinical assessment, which prioritized observation of arousal-like behaviors in a clinical setting, but also incorporated parent-child self-reports such as the Treatment Emergent Suicide and Activation Assessment Profile (TEASAP) . During fMRI scans, participants viewed a series of stimuli and were asked to press a button when presented with an infrequent target (circles) against the background of rare distractors and more common standard items (squares). Distractors were emotional or neutral images.

Analysis of the fMRI data was performed using the CONN 21a toolbox in MATLAB. ROI analyzes for functional connectivity ROI were performed using the Harvard-Oxford Atlas-based insular cortex (INS), orbitofrontal cortex (OFC), amygdala (AMY), inferior frontal gyrus (IFG), pars opercularis and Pars triangularis, and cingulate previous performed. seed coat regions (ACCs). Differences in functional connectivity between emotional and neutral distractors were compared at baseline and between baseline and EH scans. Contrasts were analyzed using repeated measures ANOVA and mixed random effects ANOVA. Significant ROI-ROI connectivity differences with threshold were reported at p-FDR group level < 0.05.

Results:Changes in functional connectivity in participants who developed DH after treatment:

At baseline, participants who developed DH while on escitalopram treatment showed no statistically significant differences in ROI-ROI functional connectivity when comparing emotional and neutral stimuli. However, over time, HD participants showed greater connectivity between the left IFG-pars opercularis and the left insula (p-FDR =0.0105) and between the left IFG-pars opercularis and the right insula (p- FDR = 0.0105) when comparing stimuli with neutral stimuli.

Changes in functional connectivity in participants who developed HD and matched subjects after treatment: Compared to matched subjects, participants who developed HD had no significant baseline differences in functional connectivity when contrasting emotional and neutral stimuli. Over time, participants who developed HD showed greater connectivity between ACC and left triangular IFG (p-FDR =0.0075) compared to matched subjects.

Conclusions:Adolescents with a family history of TB who developed DH while on escitalopram treatment showed no difference in frontolimbic functional connectivity at baseline. However, there are longitudinal changes in emotional processing circuits over the course of escitalopram treatment, suggesting that SSRIs may play a role in mediating disturbances in these fronto-limbic neural circuits. Due to the small sample size of 14 HD participants, further studies are needed to confirm these results. Our results suggest that a larger sample of at-risk adolescents is needed to elucidate the mechanisms underlying treatment-induced HD and discover potential targets for pharmacotherapy in this patient population.

Key words:Bipolar disorder, functional MRI, task-based functional connectivity, emotional arousal

Disclosure:Janssen Pharmaceuticals: Speakers Bureau (auto), Janssen Pharmaceuticals: Advisory Board (auto), Otsuka: Speakers Bureau (auto)

Patricia Burhunduli, Zhuo Fang, Katie Vandeloo, Pierre Blier, Jennifer Phillips*

University of Ottawa Mental Health Research Institute, Ottawa, Canada

Background:Suicide remains one of the leading causes of preventable death, although predicting and reducing suicidal behavior remains a challenge. Studies have shown that suicide cannot be explained only as a catastrophic consequence of major depressive disorder (MDD), but that risk factors are diverse and neurobiological processes play an important role. Studies have shown that aberrant neural networks may be involved in suicidal thoughts and behavior. This study evaluated differences in functional connectivity (FC) at rest between suicidal ideation (SI) and suicide attempt (SA) in patients with treatment-resistant MDD.

Methods:The sample consisted of N = 40 patients with therapy-resistant MDD (n = 21 with suicidal thoughts, n = 19 with a suicide attempt). Resting-state functional magnetic resonance imaging (fMRI) data were acquired in 3T and preprocessed using the standard CONN functional connectivity pipeline. Group-level differences in functional connectivity at rest between patients with SI and AS were filled in using a region of interest (ROI) approach to ROI. SI and AS were clinically characterized using the Columbia Suicide Severity Rating Scale (C-SSRS); Comparisons were statistically significant at pFDR ≤ 0.05.

Results:Functional connectivity of the right hippocampus at rest and the default mode network (DMN) (bilateral lateral parietal lobe) were increased in patients with IS compared with AS (pFDR = 0.02). Connectivity of the DMN (right lateral parietal lobe) and regions within the prominence network such as the anterior cingulate cortex (ACC) and bilateral supramarginal gyrus (SMG) were significantly reduced in the SI group (pFDR = 0.03). Functional connectivity between the caudate and posterior hippocampus/parahippocampus was negatively correlated with current SI severity in the entire patient sample (N=40; pFDR=0.05) and particularly in the experimental group (n=19; pFDR=0.008).

Conclusions:Our preliminary resting-state fMRI analyzes show significant differences in functional DMN connectivity in patients with a history of suicide attempts compared to patients with only suicidal ideation. There were significant associations between functional limbic network connectivity and current severity of suicidal ideation. These results support possible neural circuitry involved in the neurobiology of a history of suicidal ideation and suicide attempt in patients with treatment-resistant MDD.

Key words:Functional connectivity at rest, suicide attempt, suicidal ideation, treatment-resistant depression, MRI

Disclosure:Nothing to disclose.

Beatrix Krause, Prabha Siddarth, Hanadi Ajam Oughli, Lisa Kilpatrick, Katherine Narr, Helen Lavretsky*

UCLA Semel Institute for Neuroscience and Human Behavior, Los Angeles, California, USA

Background:Geriatric depression (GD) is associated with significant medical comorbidity, cognitive decline and brain atrophy, premature mortality, and suboptimal response to treatment. Although apathy and anxiety are common comorbid symptoms in GD, resilience has been shown to be a protective factor. Understanding the relationship between brain morphometry and symptoms and resilience in GD can inform clinical management goals. Gray matter volume (GMV) is altered in GD, but correlations with mood symptoms and particularly resilience are less available.

Methods:49 adults over 60 years old. (38 women) diagnosed with major depressive disorder while being treated with antidepressants participated in the study. Depressive symptoms, as well as apathy, anxiety and resilience were assessed in conjunction with T1-weighted anatomical MRI. We used a general linear model (GLM) to identify groups in which the GMV correlated with each measure. Freesurfer 6.0 was used to process T1-weighted images and perform GLM in whole-brain voxel form using age and gender as covariates. Partial Spearman correlations, controlling for age and gender, were used to examine the association between clinical variables.

Results:As expected, greater depression severity was associated with greater anxiety (r = 0.53, p = 0.0001). Greater resilience was associated with less depression (r = -.33, p = .03) and less apathy (r = .39, p = .01). Higher GMV in generalized and partially overlapping clusters across the brain was associated with reduced anxiety and apathy and increased exercise tolerance.

Conclusions:Our results suggest that GMV is a potential marker of resilience in GD in large brain regions and overlaps with GMV markers for depression and anxiety in certain smaller regions. As resilience is a protective factor against depression, future studies should examine GMV changes in these regions with treatment.

Key words:Depression, MRI, resilience, apathy, anxiety

Disclosure:Nothing to disclose.

Chris Ritter, Andreas Buchmann, Sabrina Muller, Martin Volleberg, Melanie Haynes, Carmen Ghisleni, Ralph Noeske, Ruth Tuura, Gregor Hasler*

University of Fribourg, Villars-sur-Glâne, Switzerland

Background:In MDD, disturbances of the major inhibitory and excitatory neurotransmitters, γ-aminobutyric acid and glutamate, respectively, as well as Glx (glutamate + glutamine) have been widely reported in various areas of the brain, but few studies have examined changes in glutamine, the metabolic counterpart of synaptic glutamate. In this study, we examined changes in voxel glutamate, GABA, Glx, and glutamine levels in the left dorsolateral prefrontal cortex of participants without prior and current major depressive disorder in a large non-drug sample recruited from the general population. 🇧🇷

Methods:Cross-sectional design using 3-T 1H-MRS in community recruited participants. Our sample consisted of 251 healthy controls, 98 individuals with a history of major depressive disorder, and 47 individuals who met diagnostic criteria for current major depressive disorder. The diagnostic groups were comparable in terms of age, education, income and diet. Our main outcome measures were GABA, glutamate, and glutamine concentrations in the left dorsolateral prefrontal cortex.

Results:Participants with a prior major depressive disorder had lower levels of glutamate (r=0.162, p=010, n(healthy; former MDD)=234.93) and GABA (r=0.184, p=002, n(healthy; former MDD) = 236, 92) and higher glutamine levels (r = 0.165, p = 0.043, n (healthy; past MDD) = 153, 66) compared with participants without major depression. GABA concentrations were negatively associated with acute depressive symptoms (HAMD: rho = -.117, p = .022, n = 322, MADRS: rho = -.125, p = .018, n = 362, BDI: rho = -.150, p=005, n=363), while glutamine was positively associated with neuroticism (rho=0.202, p=002, n=240).

Conclusions:In a large drug-free community sample, reduced prefrontal GABA concentrations were associated with past and current major depressive disorders, consistent with histopathologic studies reporting reduced glial cell density and GABA in the prefrontal cortex at depression. Patients with major depressive disorder also had elevated glutamine levels, indicating increased synaptic release of glutamate, adding to previous evidence supporting the glutamate hypothesis in major depressive disorder.

Key words:Gutamate, Glutamine, GABA, Depression

Disclosure:Nothing to disclose.

Benjamin Goldstein*, Nilesh Ghugre, Idan Roifman, Brian McCrindle, Bradley MacIntosh, Kody Kennedy

Centre for Addiction and Mental Health, Toronto, Canadá

Background:Cardiovascular disease (CVD) occurs disproportionately and prematurely in bipolar disorder (BD), even after controlling for traditional cardiovascular risk factors. The increased risk of CVD in BD may be exacerbated by microvascular dysfunction. We set out to expand the previous literature on coronary microvascular dysfunction in psychiatric populations, focusing on BD in youth.

Methods:Participants were 86 young people aged 13 to 20 years (n = 39 BD, n = 47 controls). Coronary microvascular reactivity (CMVR) was assessed using blood oxygen-dependent T2-weighted magnetic resonance imaging including an established apnea paradigm. Images were acquired during normal (baseline) breathing, after 60 seconds of hyperventilation, and every 10 seconds during a 40-second breathing pause. Measurement of left ventricular structure (eg, mass, volume) and function (eg, ejection fraction) was evaluated based on 12-15 long-axis and short-axis cardiac cine images. A linear mixed-effects model controlling for age, sex, and body mass index, evaluated for between-group differences in CMVR (ie, one interaction per group).

Results:The respiratory paradigm induced a significant change in T2 relaxation time in the total sample (ie, CMVR; β = 0.36, p < 0.001). CMVR was significantly lower in BD vs. HC (β = -0.11, p = 0.004). Paired post-hoc analyzes showed that significant differences between groups were evident after 30 and 40 seconds of apnea (p = 0.003 and p < 0.001, respectively). Measurements of left ventricular structure and function were within normal limits and did not differ significantly between groups.

Conclusions:There was evidence of coronary microvascular dysfunction despite normal cardiac structure and function in adolescents with BD. These results are consistent with previous results for adults with major depressive disorder and post-traumatic stress disorder. Future studies integrating larger samples, prospective follow-up and blood biomarkers are needed.

Key words:Bipolar disorder, cardiac reactivity, BOLD fMRI signal, adolescent

Disclosure:Nothing to disclose.

Danella Hafeman*, Feldman Jamie, Mary Phillips

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:Mood lability, defined as frequent and marked changes in mood, is a predictor of the occurrence of mood disorders, psychosocial dysfunction, and suicidal ideation and behavior. Given the clinical relevance, it is important to better characterize this phenotype, including the neural basis. In recent years, whole-brain predictive approaches (e.g., predictive connectome modeling) have emerged as useful tools for assessing the degree to which edge strengths predict a given phenotype (e.g., anxiety or irritability) using a cross-validation approach. . However, the interpretability of the networks resulting from these analyzes is limited. Network-based statistics (NBS) is an approach developed over a decade ago that identifies networks associated with a phenotype; Recently, this approach has been adapted to a predictive context using k-fold cross-validation (NBS-Predict). The combined use of NBS and NBS-Predict has the potential to identify reproducible and interpretable networks associated with a mood lability phenotype.

Methods:We recruited 69 young people between 10 and 15 years old with a family history of bipolar disorder; 33 of them were selected because of their high level of mood lability (defined as an average >10 on the Child and Adolescent Parent Self-Reported Lability Scale, CALS). We also scanned 42 age- and sex-matched healthy controls. Family history was confirmed by structured clinical interview for DSM-IV (mania and depression sections) and/or medical records. Adolescents were assessed using the Childhood Schedule for Mood Disorders and Schizophrenia, Present and Lifelong; they also received several questionnaires, including the CALS. Adolescents underwent MRI on a 3T scanner (Verio or Prisma) that included a 6-minute resting state protocol. Data were analyzed with fmriprep (20.2.6 LTS) and xcp-d (stable version), fit motion, global signal and derivatives (36p model). Participants with excessive movement (mean frame shift   > 0.5 mm or maximum movement > 3 mm; n = 14) or artifacts observed on visual inspection (n = 1) were excluded, resulting in 96 participants with acceptable data (58 risk patients, 38 healthy controls). Using nilearn, we extract time series from the Shen graph (268 graphs) and generate connectivity matrices. We then used NBS-Predict to test predictive models for risk status (at risk versus healthy) and mood lability; all models corrected for scanner, average image offset, age and gender. The models were cross-validated 5 times (10 iterations) using the optimized prediction model (established in the training set) and thresholds of p < .01 and p < .05 with 5000 permutations. NBS (v1.2) was used for further exploratory modeling, including tests for separately signed networks and tests for CALS as a dichotomous predictor.

Results:Using an individual threshold slope of p < .05, we identified a network that predicted mood lability (correlation: 0.335 (0.299, 0.371), p =0.017), explaining 10.3% of the variance. We restricted ourselves to the most influential edges (threshold weight = 1) and found 52 edges (15 positively correlated; 37 negatively correlated). Visual networks (especially Visual II) were strongly represented on selected edges. Visual II connectivity to the motor, prominent, and frontal-medial networks correlated with lower mood lability, while visual II frontoparietal network connectivity correlated with greater mood lability. Testing the networks in NBS, we found a significant network that was negatively correlated with mood lability (5000 permutations, p = 0.004); a positively correlated network approached significance (5,000 permutations, p = 0.055). These networks largely overlap with those identified by NBS-Predict, but with more nodes in the frontal-medial and frontoparietal networks. By dichotomizing mood lability into a median split (10), we found a significant network that negatively predicts mood lability. It was not possible to rank risk with NBS-Predict compared to healthy controls; Likewise, the NBS did not identify any significant networks between these two groups.

Conclusions:We found that a connectome-based approach identified a network (consisting of negative and positive edges) that predicted mood lability in a sample of healthy controls and at-risk adolescents. Although we hypothesized that the subcortical and medial frontal networks would be most strongly correlated with mood lability, we were surprised to find that the primary visual cortex was strongly represented in the predictive network. Surprisingly, greater connectivity between the visual and motor context (anatomically consistent with the visual dorsal stream) was associated with less mood lability. Interestingly, previous work has shown that the visual dorsal current is activated by natural emotional stimuli and may be important in preparing for action; In this way, greater connectivity within the dorsal stream may improve emotion regulation strategies and thus reduce mood lability. While NBS and NBS-Predict produced similar edges, an important difference is that prominent networks in NBS (eg, medial frontal) were not as prominent in NBS-Predict results; this may be related to their out-of-sample performance. While k-fold cross-validation improves the reproducibility of results, the gold standard approach is out-of-sample replication; In the future, we plan to test this model on an independent sample of at-risk youth.

Key words:Mood dysregulation, resting state fMRI, familial risk of bipolar disorder

Disclosure:Nothing to disclose.

Polymnia Georgiou*, Ta-Chung M. Mou, Liam E. Potter, Xiaoxian An, Panos Zanos, Michael S. Patton, Katherine J. Pultorak, Sarah M. Clark, Vien Ngyuyen, Chris F. Powels, Katalin Prokai-Tatrai, Istvan Merchenthaler, Laszlo Prokai, Margaret M. McCarthy, Brian N. Mathur, Todd D. Gould

University of Wisconsin Milwaukee, Milwaukee, Wisconsin, USA

Background:Depression is the leading cause of disability worldwide, affecting approximately 16% of the population. Although women are twice as likely to be diagnosed with depression as men, approximately 109 million men worldwide have the condition. In addition, men who suffer from depression are at greater risk of losing their lives to suicide, one of the most common symptoms of depression, with the suicide rate being four times higher in men than in women. In vulnerable populations, stress is an important risk factor for the development of mental disorders, including depression. Although the role of estrogen receptors in the pathophysiology of depression and as treatment targets in women is well understood, their role in men is not well understood.

Methods:We used a subthreshold stress model for social defeat, consisting of three cycles of two-minute physical stress and fifteen-minute sensory stress, in combination with immunohistochemistry, neuronal scanning, RNAscope, in vitro electrophysiology, in vivo optogenetics, in vivo chemogenetics, and photometry. of fiber and surgical/pharmacological manipulations of hormones to investigate the role of estradiol and its receptors in the development of social avoidance and anhedonia in male and/or female mice (n=10-15/experimental group). Statistical analysis was performed using ANOVA followed by post hoc Holm-Sidak analysis. If the criteria for parametric analysis were not met, the Kruskal-Wallis test was performed, followed by a two-step linear augmentation procedure according to Benjamini, Krieger and Yekutieli.

Results:We found that estrogen receptor-β (ERβ) absence is associated with stress susceptibility in male mice, but not in female mice, after exposure to a mild stressor and infusion of a specific ERβ agonist into the basolateral tonsils (BLA). stress in men. rats. We identified a dense projection expressing ERβ from the BLA to the nucleus accumbens (NAc), and optogenetic stimulation of this projection led to the development of a real-time location preference for the light-paired compartment in male mice, whereas females did not show any preferences. . between paired and unpaired compartments, suggesting a sex-dependent effect of this circuit. Furthermore, we observed that the activity of these neurons is reduced in male gonadal hormone depleted mice under mild stress and this is associated with stress susceptibility. Furthermore, we show that optogenetic activation of this circuit reverses stress-induced maladaptive behavior and induces stress resilience in hypogonadal mice, whereas chemogenetic inhibition of this circuit induces a stress-prone phenotype in intact mice after mild stress. Estradiol (E2), often considered a female hormone, is distributed in the male brain through the aromatization of testosterone. We found that lack of E2, but not testosterone per se, underlies susceptibility to the development of maladaptive behaviors in men after exposure to mild stress. Using selective delivery of E2 to the brain via prodrug administration, which offers a viable treatment option in males, we show that E2 prevents the development of depression-related behaviors after acute/mild stress in male mice.

Conclusions:Taken together, our results provide evidence for an estrogen-based mechanism underlying stress susceptibility and suggest a novel therapeutic strategy using brain-selective estradiol to treat depression in men.

Key words:Estradiol, depression, neural circuitry and animal behavior, estrogen receptor

Disclosure:A patent has been filed for the development of brain-selective estradiol compounds: Patent (own)

Liisa Hantsoo*, Zachary Kaminsky, Jennifer Payne

Johns Hopkins University, Baltimore, Maryland, USA

Background:Premenstrual dysphoric disorder (PMDD) is considered a type of reproductive affective disorder and is characterized by affective symptoms that appear in the luteal phase of the menstrual cycle and resolve in the follicular phase. The pathophysiology of PMDD is poorly understood, although genetic vulnerabilities, including epigenetic alterations, may contribute. Previous research has found variations in DNA methylation that predict postpartum depression (another affective reproductive disorder) with up to 80% accuracy. This study examined these epigenetic markers in women with PMDD compared to healthy controls in the follicular and luteal phases to determine whether these biomarkers were specific for postpartum depression or more general biomarkers of reproductive mood disorders.

Methods:Control and PMDD female participants were recruited from the community and completed two months of daily prospective symptom assessments (Daily Problem Severity Record (DRSP), a standard measure of premenstrual symptoms) to assess control or PMDD status, confirmed by a SCID interview. Blood was collected during the follicular (days 5-11 of the menstrual cycle) or luteal (days -7 to -1 of the menstrual cycle, confirmed by a urine luteinizing hormone test and serum progesterone levels ≥3 ng/mL). Additionally, women with PMDD were treated with 50 mg of the selective serotonin reuptake inhibitor (SSRI) sertraline during a subsequent luteal phase and characterized as responders or non-responders based on at least a 30% reduction in the DRSP score. Blood samples were subjected to sodium bisulfite pyrosequencing on the TTC9B and HPIBP3 genes and our established and published linear PPD biomarker model was used to assess whether our model of postpartum depression could predict PMDD status compared to controls and predict additionally the response to SSRIs in PMDD participants.

Results:Blood samples were available for fifty-five participants (n=26 controls, n=29 PMDD); 23 in the follicular phase and 32 in the luteal phase. Follicular samples failed to distinguish PMDD cases (N=13) from controls (N=9). However, luteal phase samples were able to discriminate PMDD cases (N=10) from controls (N=18) with an AUC of 0.71 (95% CI: 0.49-0.93). Our methylation biomarkers were also able to distinguish between SSRI responders (N=5) and SSRI non-responders (N=5) using luteal phase blood with an AUC of 0.84 (95% CI: 0.57-1).

Conclusions:This study examined CpG methylation levels at two loci in the HP1BP3 and TTC9B genes. We found that methylation patterns in these two genes can discriminate between PMDD cases and controls, but only when luteal phase blood was used, indicating that hormonal changes that occur during the luteal phase may be important. Our methylation biomarkers were also able to discriminate between SSRI responders and non-responders in PMDD cases when using luteal phase blood. Research on postpartum depression, another affective reproductive disorder, suggests that these loci may mediate sensitivity to changes in estrogen that occur during and after pregnancy, suggesting that they may also identify women who are sensitive to hormonal changes that occur during the luteal phase of pregnancy. pregnancy. pregnancy. the menstrual cycle. Our results also indicate that there may be biological differences between responders and non-responders to SSRIs. We hope to replicate these results in a large sample of PMDD cases and controls and examine the ability of our biomarker to predict case status in other types of reproductive mood disorders.

Key words:Epigenetic biomarkers, reproductive affective disorder, premenstrual dysphoric disorder, allopregnanolone, estradiol

Disclosure:Nothing to disclose.

Sarah Rudzinskas*, Maria Mazzu, Allison Goff, Crystal Schiller, Samantha Meltzer-Brody, David Rubinow, David Goldman, Peter Schmidt

National Institute of Mental Health, NIH, Rockville, Maryland, USA

Background:Given the health implications, social burden, and prevalence of postpartum depression (PPD), the recent FDA approval of brexanolone was an encouraging advance in the treatment of PPD. Allopregnanolone (ALLO), the natural steroid metabolite of progesterone chemically identical to brexanolone, is thought to exert its anxiolytic and antidepressant effects through positive allosteric modulation of GABA A receptors. molecular level and whether this mechanism is specific to PPD remains unclear.

Methods:We examined the consequences of exposure to ALLO by transcriptomics on lymphoblastoid cell lines (LCL) derived from women with a history of postpartum depression (n = 9) and women without a history of postpartum depression or other psychiatric disorders (n = 10, i.e. controls). ) he came. 🇧🇷 All LCL were treated with ALLO (three peaks, 100 nM/peak) or DMSO vehicle for a total of 60 hours, creating four different experimental groups: Control:DMSO, Control:ALLO, PPD:DMSO and PPD:ALLO. LCL were then collected for AmpliSeq RNA sequencing and analyzed for differential gene expression 1) between control and PPD LCL, at baseline (control:DMSO vs. PPD:DMSO) and after ALLO treatment (control:ALLO vs. .PPD:ALLO) and analyzed 2) into the control (Control:DMSO vs. Control:ALLO) or PPD LCL (PPD:DMSO vs. PPD:ALLO). Quality control, unsupervised clustering, and expression analyzes were performed in Transcription Analysis Console (TAC) 4.0, and Weighted Gene Correlation Network Analysis (WGCNA) was performed in R.

Results:Differentially expressed genes (DEG, p(nom)<0.05, log(fold change)>=|1.25| ) were detected within and between PPD and control LCL after ALLO treatment. Between Control:ALLO and PPD:ALLO, 269 DEGs were observed and Enrichr revealed many associated with synaptic activity. Among these DEGs was glutamate decarboxylase 1 (GAD1), which was significantly decreased in PPD:ALLO compared to control:ALLO LCL (p(nom)<0.019). Replication technique using qRT-PCR confirmed that GAD1 expression was decreased in PPD-LCLs compared to controls (diagnosis: F(1,34)=5.25, p=0.0283), but ALLO had no impact significant in expression (treatment: F(1.34) )=0.006121; Interaction: F(1.34)=0.0108). Overall gene expression patterns also showed that regardless of ALLO treatment, diagnosis was the main reason for expression differences, suggesting a robust effect of PPD on gene expression, consistent with previous data (Rudzinskas et al., in review) . Surprisingly, significantly more DEGs were induced by ALLO treatment in LCL control (control:DMSO vs. control:ALLO, 265°) compared to PPD-LCL (PPD:DMSO vs. PPD:ALLO, 98°), with only 363 of these in total, 11 were DEGs related to ALLO overlap. Consequently, gene-set enrichment analysis using MSigDB showed that networks associated with PPD:DMSO vs. PPD:ALLO DEG were unique to and sometimes opposed to Control:DMSO vs. Control:ALLO DEG. Likewise, WGCNA showed statistically significant modules related to treatment or diagnosis; No significant modules were observed for PPD or ALLO.

Conclusions:Together, these data elucidate ALLO-dependent and independent molecular responses in PPD. Although Control:ALLO vs. PPD:ALLO reflect the literature supporting ALLOs modulation of synaptic signaling and GABA-related activity, the poor response of PPD-LCLs to ALLO treatment, particularly when compared to control LCLs, warrants further investigation. 🇧🇷 Furthermore, the notable lack of overlap in DEGs between diagnostic groups after ALLO treatment suggests that ALLO activates unique and possibly divergent cell signaling pathways in women with PPD compared to controls. Therefore, it may be beneficial to recognize ALLO's ability to perform various diagnostic-dependent cellular functions when considering its therapeutic potential.

Key words:Postpartum depression, allopregnanolone, transcriptomics

Disclosure:Nothing to disclose.

Rachel Zsido, Angharad Williams, Claudia Barth, Bianca Serio, Luisa Kurth, Frauke Beyer, Veronica Witte, Arno Villringer, Julia Sacher*

Emotional Neuroimaging Laboratory (EGG), Max Planck Institute for Brain and Cognitive Sciences, Clinic for Cognitive Neurology, University of Leipzig, Leipzig, Germany

Background:Women-specific variables such as pregnancy, menopause, and the menstrual cycle affect the brain and risk of mental health disorders, and women are at greater risk for cognitive and mood disorders when ovarian hormones fluctuate and fall rapidly. However, only 3% of neuroscientific studies are conducted exclusively on women, resulting in a large data gap. Here we provide the first longitudinal high-field MRI dataset of the hippocampus across the menstrual cycle, showing the natural variation in structural plasticity of the female brain in a region critical for memory and affect regulation.

Methods:We performed longitudinal mapping of the morphology of the medial temporal lobe subregion at 6 time points across the menstrual cycle in vivo using a dense sampling protocol, ultrahigh-field neuroimaging, and individually derived segmentation analysis in 27 healthy study participants. female gender (19-34 years old). 🇧🇷

We acquired a total of 138 high-resolution images for hippocampus and medial temporal lobe volumetric calculations. Using this powerful design within subjects, we performed a new segmentation analysis of high-resolution 7 Tesla MRIs to investigate whether volumetric changes modulated by ovarian hormones manifest differentially in subregions of the medial temporal lobe complex. We also quantified cerebrospinal fluid and cerebral blood flow to confirm that the volumetric changes were not caused by hormone-induced fluid changes or changes in blood flow.

Results:As already mentioned, the linear mixed-effects model showed positive associations between estradiol levels and total hippocampal volume (β = 108.26, 95% CI = 27 to 190, SD random effects = 174.47, p = 0.009 ). In the MTL subregions, the addition of the estradiol*progesterone interaction to the model significantly improved the model fit for CA1 only (χ2(1) = 7.691, p = 0.006). Estradiol was positively associated with CA1 volume (β = 42.87, 95% CI = 21 to 65, p < 0.001), progesterone was negatively associated with CA1 volume (β = -150.02, 95% CI = - 249 to -51, p = 0.003), and we observed a significant interaction of estradiol and progesterone with CA1 volume (β = 53.06, 95% CI = 16 to 90, random effects SD = 44.03, p =0.005) , so that at higher levels of progesterone, the positive effect of estradiol on CA1 volume was attenuated. Progesterone was positive with subiculum volume (β=13.12, 95% CI=4 to 22, random effects SD=43.29, p=0.006) and area volume 35 (β=11.98, 95% CI = 2 to 21, random effects SD) associated = 44.01, p = 0.014). Finally, estradiol was positively associated with parahippocampal cortex volume (β = 24.33, 95% CI = 10 to 39, random effects SD = 32.48, p = 0.001).

Conclusions:We found unique associations between ovarian hormones and CA1, perirhinal area 35, subiculum, and parahippocampal cortex volume across the menstrual cycle. These results suggest that ovarian hormones alter brain structural plasticity in brain subregions that are differentially hormone sensitive. To recognize female brain health as more than just how female brains differ from male brains, female-specific variables such as menstrual cycle should be highlighted as the main variable of interest. By providing detailed neural phenotyping of brain areas crucially involved in cognitive and neurodegenerative diseases, we have established an important benchmark: an integrative benchmark for assessing female MRI biomarkers in health and disease, and a prerequisite for definitively assessing depression and dementia risk. later in life. Conditions that affect women twice as often as men and more often at times of changes in the hormonal environment of the ovaries.

Key words:Human Neuroimaging, Hippocampus, Menopause, Humor, Childhood Stress, Neuroendocrinology, Women's Health, Gender Differences

Disclosure:Nothing to disclose.

Natalia Duke-Wilckens*, Dimitri Joseph, Maradiaga Nidia, Srinivasan Vidhula, Szu-ying Yeh, Hari Subramanian, Eric Nestler, Adam Moeser, Alfred Robison

Michigan State University, Bath, Michigan, USA

Background:Brain inflammation plays a central role in neurodegenerative and psychiatric diseases, but the mechanisms by which events such as peripheral infection or environmental stressors result in sustained central neuroimmune activation remain unclear. Mast cells, the innate immune cells best known for their role in allergies, are uniquely positioned to play a key role in amplifying the inflammatory response that leads to chronic brain disease. In addition to various peripheral tissues, mast cells are found in the brain and meninges, are highly sensitive to immune challenges and stress (which can permanently alter their activity), and can release an impressive array of bioactive molecules ranging from pro-inflammatory and anti-inflammatory cytokines to proteases and neurotransmitters that directly affect brain physiology. Surprisingly, the transcriptional mechanisms that control acute and long-term mast cell responses remain largely unexplored. Based on the initial findings that stress- and antibody-mediated mast cell activation dramatically increases the expression of FosB, which encodes the transcription factors FosB and ΔFosB, which are critically involved in the long-term modulation of neuronal activity, we used transgenic mice in combination with in vitro and in vivo experiments to test the hypothesis that FosB plays a central role in the regulation of stimulus-induced mast cell activation and mediator release.

Methods:1) To create the first mice in which FosB expression in mast cells is specifically repressed (MCFosB-), we crossed Mcpt5-Cre with Cre-dependent FosB mouse strains. 2) For in vitro experiments, bone marrow progenitor cells were collected from the femurs of WT and MCFosB mice and cultured in medium supplemented with stem cell factor and Il-3 for 6 weeks to generate bone marrow derived mast cells (BMMC) . Several approaches have been used to assess BMMC responses to stimulation with IGE or lipopolysaccharide (LPS) antigens: electron microscopy, intracellular measurements of Ca2+ and mediator release. Finally, to confirm the role of FosB in mast cell activity, we overexpressed ΔFosB or its dominant negative binding partner ΔJunD in WT and MCFosB-BMMC 3) For in vivo experiments, male and female WT and MCFosB mice were subjected to anaphylaxis by the injections levels of LPS and rectal temperature, peripheral and central release of inflammatory mediators, and levels of mesenteric mast cell activation were evaluated. 4) Finally, to discover ΔFosB binding regions in mast cell chromatin, we performed CUT and RUN with reference antigen-activated IGE and BMMCs and combined these data with RNAseq analysis to find potential genes that are directly regulated by ΔFosB after stimulation. 5) Statistical Analysis: Sample sizes were n=3–6 for in vitro studies and 8–10 for in vivo studies. Depending on the experimental design, t-tests, two-way ANOVAs or repeated measures ANOVAs were used.

Results:1) MCFosB-derived BMMCs do not express FosB or ΔFosB and show a more activated appearance at baseline and after stimulation, as well as greater stimulus-induced Ca2+ mobilization and pro-inflammatory mediator release compared to WT (p < 0.001) . Preliminary data suggest that overexpression of ΔFosB inhibits stimulus-induced mediator release in WT and MCFosB-BMMC, whereas ΔJunD exerts the opposite effect. 2) MCFosB mice show exaggerated hypothermic responses (p < 0.01), increased levels of inflammatory cytokines in plasma and hypothalamus (both p < 0.05) and increased activation of mesenteric mast cells (p < 0.05). Overlapping CUT and RUN and RNAseq data suggest that functional targets of ΔFosB include the dual-specific phosphatase Dusp4 and thymic stromal lymphopoietin TSLP, known regulators of mast cell activity. We are currently validating these results using gene and protein expression analysis.

Conclusions:Taken together, these data indicate that FosB products exert an inhibitory effect on mast cell activation and the release of pro-inflammatory mediators and suggest that this effect may be mediated in part by DUSP1-mediated dephosphorylation of mitogen-activated protein kinases (MAPKs ). These results provide a new negative feedback mechanism of mast cell regulation, relevant to brain and peripheral disorders associated with aggravated inflammation.

Key words:Neuroinflammation, ΔFosB, mast cells

Disclosure:Nothing to disclose.

Kathryn Lenz*, Courtney Dye, Dominic Franceschelli, Amanda Ringland, Benedetta Leuner

The Ohio State University, Columbus, Ohio, USA

Background:Pregnancy confers a period of heightened susceptibility to mood disorders, with around 20% of new mothers suffering from postpartum depression (PPD). The mechanisms that contribute to mood dysregulation and impaired maternal care in postpartum depression are not well understood, but stress during pregnancy is an important risk factor. Previously, we found that pregnancy leads to microglial changes in brain regions that regulate maternal mood and nutrition, including the medial prefrontal cortex (mPFC) and nucleus accumbens (NAc). Pregnancy also induces widespread neuroplasticity to facilitate maternal motivation and care, and since microglia are involved in synaptic remodeling in stressed and non-stressed states, we hypothesized that microglia-mediated synaptic remodeling may contribute to depression. post childbirth.

Methods:We used a rodent model of pregnancy stress that elicits a PPD-like phenotype (ie, behavioral distress, anhedonia, impaired maternal care). Mice underwent chronic variable stress or control management (n = 8-10/group/endpoint) from gestational days (GD) 7-20 and were sacrificed on GD21 or postpartum day (PD) 8, and the brains were collected. In one cohort, qPCR was performed on mPFC and NAc tissue to measure a selected panel of synaptic transcripts. In another cohort, brains were sectioned and immunofluorescence staining was performed against a postsynaptic glutamatergic synaptic marker (PSD-95), an extracellular matrix protein marker for perineuronal networks (WFA), a pan-microglia marker (Iba1 ) and a lysosomal marker. (CD68) to identify phagocytic microglia. Staining density and 3D colocalization were quantified using ImageJ and IMARIS software. Data were analyzed using 2-way ANOVA and Tukey's post-hocs when significant main effects were found. All experimental protocols in animal studies were approved by the Ohio State University Institutional Animal Care and Use Committee and performed in accordance with the NIH Guide for the Care and Use of Laboratory Animals.

Results:The stress of pregnancy resulted in increased staining of microglia and phagolysosomes in mPFC in PD8 (p<0.05) and NAc in GD21 (p<0.05) and PD8 (p<0.0001). For NAc, pregnancy stress resulted in decreased expression of the presynaptic glutamatergic marker Vgat1 in GD21 and the common presynaptic marker synaptophysin in PD8 (p < 0.05). Stress also resulted in a decrease in PSD-95 immunostaining in the NAc (p < 0.05), but no stress-induced difference in microglial uptake of PSD-95 was observed in the Imaris 3D rendering analysis. In mPFC, neither synaptic mRNA expression nor PSD95 immunostaining were affected by stress. However, we found changes in perineuronal networks (PNNs), which are extracellular proteins responsible for synaptic stability. We found that PNNs increased in controls from GD21 to PD8 (p<0.0001) and that pregnancy stress resulted in a significant decrease in PNN levels compared to controls in GD21 (p<0.001) and PD8 (p< 0.0.01). However, there were no significant stress effects on PNN microglia uptake in the Imaris 3D rendering analysis. The NAc had little or no WFA-stained PNN in either group.

Conclusions:In PFC, PNNs but not synaptic targets were reduced by pregnancy stress. In NAc, synaptic targets were decreased by exposure to pregnancy stress. Thus, pregnancy stress has region-specific effects on the synaptic elements it affects, although both regions exhibit similar microglial changes. As the loss of PNN and synapses was not mediated by microglial phagocytosis, future work will examine degradation of these synapses and stabilization by secreted microglia-derived factors. Microglia-mediated remodeling of perineuronal networks is a novel mechanism for maternal neuroplasticity. Understanding how postpartum perineuronal stress remodeling may contribute to the underlying pathophysiology of postpartum depression is an interesting avenue for future research and intervention strategies.

Key words:Postpartum depression, microglia, medial prefrontal cortex, stress, synapses

Disclosure:Nothing to disclose.

Paula Gajewski-Kurdziel*, Alaina Tillman, Hideki Iwamoto, Nicole Baganz, Matthew Robson, Ning Quan, Randy Blakely

Florida Atlantic University, Jupiter, Florida, USA

Background:Several neuropsychiatric disorders have been identified as having a compromised immune system (Kerr et al., 2005). The high comorbidity of neuropsychiatric diseases with chronic inflammatory diseases, such as rheumatoid arthritis, suggests a similarity in the manifestation of these diseases (Evans et al., 2005). Inflammatory cytokines have been found to affect multiple dimensions of neuronal signaling, from neurotransmitter release and transport to neuronal excitability and plasticity (Capuron and Miller, 2011). Dorsal raphe (DR) neurons, which project serotonin (5-HT) into the forebrain, play important roles in regulating behaviors related to mood, anxiety, sleep, eating, and social interactions. Dysfunction in 5-HT neurotransmission is believed to contribute to various neuropsychiatric disorders. Our work focuses on identifying molecular and circuit-level mechanisms that can translate peripheral innate immune activation into behavioral changes. We report that peripheral activation of the innate immune system rapidly increases serotonin transporter (SERT) activity, a major determinant of 5-HT neurotransmission (Zhu et al., 2010). Several groups, including ours, demonstrated high levels of IL-1R1 expression in 5-HT neurons (Okaty et al., 2015; Liu et al., 2019). Identifying the projections and physiological consequences of IL-1R1 neurons that express 5-HT may shed light on how the immune system can influence behavior through discrete circuits and lead to refined treatments for behavioral disturbances present in neuropsychiatric disorders.

Methods:We used adult male and female transgenic mice capable of conditional IL-1R1 deletion (IL-1R1loxP/loxP) or IL-1R1 restoration in an IL-1R1 knockout background (IL-1R1r/r). Mice received LPS (0.2 mg/kg i.p.) or saline and sacrificed by transcardiac perfusion three hours after treatment (n=8-12). Brain sections containing DR were immunostained with 5-HT and cFos, and colocalization scores were obtained from a blinded observer. 5-HT projection sites were stained for cFos (DAB) and cell numbers were obtained by automated counting (Nikon NES Elements Software). 5-HT uptake assays in midbrain synaptosomes were performed after peripheral LPS with or without the presence of serotonergic IL-1R1. Candidate projection sites were selected for stereotaxic surgery to inject the retrograde marker Fluorogold (FG) into ePet1:Cre;IL-1R1r/r mice to visualize serotonergic colocalization of IL-1R1 (via a transcriptional reporter). In vivo chronoamperometry was used to determine the effect of local IL-1β (2 ng) on ​​5-HT clearance in the dorsal hippocampus (CA3) of male wild-type mice. Sharp recordings of brain slices of DR 5-HT neurons were obtained using a whole cell patch clamp with current injection used to produce a tonic trigger. IL-1β (10 ng/ml) was infused into the section and recordings were made.

Results:We show irregular IL-1R1 expression in DR subregions containing 5-HT neurons. Serotonergic IL-1R1 shows marked accumulation in the dorsal and dorsolateral subregions of the RD. After peripheral LPS treatment, males showed an IL-1R1-dependent decrease in serotonergic cFos throughout the DR, whereas females only in a subset of DR regions had reduced cFos levels. Examination of the middle raphe revealed a female-specific decrease in serotonergic neuronal activity dependent on IL-1R1 expression. The lateral habenula (LHb) appears to be a direct target of IL-1R1 serotonergic neurons, and we observed a female-specific IL-1R1 serotonin-dependent decrease in LHb neuronal activity after LPS. Other brain regions depended on serotonergic expression of IL-1R1 to maintain basal neuronal activity. Furthermore, we show that the ability of peripheral LPS treatment to stimulate SERT in midbrain synaptosomes is lost after serotonergic knockdown of IL-1R1. Local application of IL-1β to the CA3 subregion of the dorsal hippocampus resulted in increased 5-HT clearance, while electrophysiology of ex vivo DR slices revealed inhibition of firing of 5-HT neurons in response to IL-1β. Reversal potential analysis suggests a role for membrane K+ channel activation as the underlying effect of IL-1R1.

Conclusions:Our results support the growing understanding that 5-HT neurons contribute to changes in CNS physiology following activation of the peripheral immune system. Our studies are among the first to demonstrate a sexual specificity of serotonergic IL-1R1 in the regulation of neuronal 5-HT activity. Because subregions of DR 5-HT neurons exhibit unique projection patterns, differences in 5-HT neuron activity after LPS in males and females suggest a basis for sex differences in projection targets, which may elicit differential behavioral responses. Our results show that IL-1β modulates 5-HT neurotransmission by both regulating SERT and repressing 5-HT activation and therefore 5-HT release. Our current efforts aim to study the activation-dependent behavior of serotonergic IL-1R1, as well as to elucidate the intracellular signaling cascade of serotonergic IL-1R1, in the hope of discovering important targets for the modulation of intrinsic 5-HT activity. Our ongoing work will further elucidate the links between heightened inflammatory signals and how these signals, acting through 5-HT signaling pathways, may ensure normal health-promoting behavioral responses and influence disease risk.

Key words:Serotonin, Dorsalraphe, Interleukin-1-Rezeptor, Interleukin-1beta, LPS

Disclosure:Nothing to disclose.

Ashutosh Tripathi*, Alona Bartosh, Danny Pérez Sierra, Anilkumar Pillai

University of Texas Health Science Center, Houston, Texas, USA

Background:Inflammation and synaptic deficits have been implicated in the pathophysiology of many neuropsychiatric disorders. Chronic stress is a major risk factor for many neuropsychiatric disorders and is known to induce inflammation and behavioral deficits. Type I interferons (IFN-I) play a key role in the peripheral inflammatory response and are responsible for mood and behavior deficits. The results of our published study identified a crucial role for complement component 3 (C3) in IFN-I-mediated changes in neuroinflammation and behavior under conditions of chronic stress. C3 is the central hub of complement activation pathways and is known to mark synapses for removal. The C3 receptor (C3ar1) is highly expressed on microglia and infiltrating monocytes/macrophages. In the present study, we hypothesize that C3ar1 activation is involved in chronic stress-induced synapse loss mediated by IFN-I signaling and behavioral deficits.

Methods:To test our hypothesis, we performed experiments using C3ar1 knockout mice. To block IFNAR signaling, mice received intraperitoneal anti-IFNAR antibodies. We used the chronic unpredictable stress (CUS) paradigm in mice. In our experiments, three-chamber tests for social behavior, Golgi staining for spinal density, immunohistochemistry to study microglia activation and synapse clipping, flow cytometry for monocyte infiltration, and qRT-PCR for measurements were performed. Data were analyzed by two-tailed Student's t-test (for two-group comparisons) or analysis of variance (ANOVA; for multi-group comparisons). p < 0.05 was considered significant. Bonferroni's post-hoc test was performed as part of the comparison.

Results:Our results show that CUS significantly increased serum IFNβ levels and social behavior deficits. Increased microglial activation and synapse loss in the prefrontal cortex (PFC) was found after CUS. Furthermore, a decreased sociability index correlated with increased inflammation and decreased number of synapses in mice exposed to CUS. Peripheral blockade of IFN-I signaling attenuated neuroimmune abnormalities and behavioral deficits induced by previous CUS. Furthermore, C3ar1 mediates IFNβ-induced systemic neuroinflammation and social behavior deficits.

Conclusions:Our results identify a key role for C3ar1 in IFN-I-mediated changes in neuroimmune changes under chronic stress. Taken together, these results support the rationale that targeting peripheral IFN-I signaling represents a promising therapeutic option, particularly for patients with an elevated immune profile, as seen in many depressed patients. More studies are needed to examine the types of brain cells responsible for C3ar1-mediated effects.

Key words:Interferon, neuroinflammation, complement component 3, loss of synapses, behavioral deficits

Disclosure:Nothing to disclose.

Ellen Doney, Laurence Dion-Albert, François Coulombe-Rozon, Natasha Osbourne, Renaud Bernatchez, Sam Paton, Fernanda Neutzling Kaufmann, Roseline Olory Agomma, Jose Luis Solano Lopez, Raphael Gaumond, Katarzyna Dudek, Joanna Kasia Szyszkowicz, Signature Consortium, Manon Lebel , Alain Doyen, Audrey Durand, Flavie Lavoie-Cardinal, Marie-Claude Audet, Caroline Menard*

Laval University, Quebec City, Canada

Background:Major depression (MDD) is currently the most prevalent mood disorder and one of the leading causes of disability worldwide. However, between 30 and 50% of patients do not respond to commonly prescribed antidepressants, indicating unexplored causative biological mechanisms. Dysfunction in the microbiota-gut-brain axis, the bidirectional communication between the central nervous system and the gastrointestinal tract, has been implicated in the pathogenesis of MDD. Consistent with the neuroimmune hypothesis of depression, MDD has a high comorbidity with inflammatory bowel diseases such as Crohn's disease and ulcerative colitis, suggesting that inflammation-related gut barrier dysfunction may affect emotion regulation and vice versa. Exposure to chronic stress disrupts the integrity of the blood-brain barrier in a sex-specific manner through loss of the tight-junction protein claudin-5, leading to the development of anxiety-like and depression-like behaviors. However, little is known about the role of the intestinal barrier in these diseases, particularly in the small intestine, where most of the absorption of food and medication takes place.

Methods:Therefore, here we examine, as chronic social stress (n=12-20/group/gender) or variable stress (n=5-10/group/gender), two models of depression in mice that affect the gut-brain barrier (JEJ ) in males. As chronic stress is the most important environmental risk factor for MDD, it is often used in animals to modify behavior and study the underlying biology. Chronic defeat social stress is a social domain-based model of depression in mice that produces two distinct stress-response phenotypes: stress-prone and stress-resistant mice. The vulnerable subgroup exhibits marked behavioral changes reminiscent of depressive symptoms in humans, with increased social avoidance, anxiety, anhedonia, hopelessness, changes in body weight, metabolic disturbances, and corticosterone reactivity. Furthermore, loss of BBB integrity only occurs in the brains of susceptible, but not resistant, mice. Another leading stress paradigm is the variable stress model, in which mice are subjected to a repetitive sequence of three stressors, namely, tube clamps, tail suspension, and foot shocks. In this paradigm, women and men develop depression-like symptoms at different times, making it a powerful model for studying gender differences. The mice were subjected to stress paradigms, followed by the analysis of gene expression profiles of targets related to the intestinal barrier by quantitative PCR, microbial composition of feces with sequencing studies and blood markers by ELISA. We also use machine learning and develop algorithms to characterize in detail the morphological changes of closed junctions. The translational value of a potential gut health biomarker was validated in human blood samples from the Montreal Signature Biobank (N = 15-29 subjects/group/sex).

Results:Altered microbial populations as well as changes in JEJ tight junction gene expression were observed depending on the type and duration of stress with sex-specific effects (Claudin-3: male social stress, unpaired bidirectional t-test). Tails p = 0.0002 vs. p = 0.288 for females; variable stress for men, two-tailed unpaired t-test p = 0.4234 vs. p = 0.0079 for women). We confirmed that stress-induced changes in tight junction gene expression are also reflected at the protein level. Thin 6 µm sections were stained twice with Cldn3 (red) and F-actin (green) and morphological analysis was performed with Imaris software (Claudin-3; unpaired two-tailed t-test p = 0.0357). Interestingly, by unsupervised k-mean clustering of four characteristics of tight junctions: frilly, width, fragmentation, and diffusion, we identified a cluster of frilly junctions in stressed animals. Frizz is associated with inflammation, so we tested whether LPS injection recapitulates stress-induced changes in JEJ and observed profound gender differences (Claudin-3: LPS treatment for men, unpaired two-tailed t-test p = 0.0001 vs. p = 0.2799 for women ). Finally, LPS-binding protein (LBP), a marker of intestinal barrier leaks, was associated with stress susceptibility in mice (for males p=0.0033 after social stress vs. females p=0.0188 after variable stress ) and the translation value was confirmed in blood. Samples of women with MDD (unpaired two-tailed t-test p=0.7285 for men vs. p=0.0434 for women).

Conclusions:Our results demonstrate that chronic stress disrupts gut barrier homeostasis, along with the manifestation of sex-specific depressive behaviors in mice and possibly depression in humans. We have developed tools and algorithms to analyze in detail the morphological changes of the tight junctions and to identify circulatory low back pain as a potential biomarker of leaky gut that could contribute to better diagnosis and informed treatment strategies for mood disorders.

Key words:Social defeat stress, gender differences, gut microbiome, gut-immune-brain axis, cytokines

Disclosure:Nothing to disclose.

Zachary Cordner*, Emese Prandovszky, Megan Pedicini, Hua Liu, Lindsey Macias, Mikhail Pletnikov, Kellie Tamashiro, Robert Yolken

Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Background:Psilocybin's therapeutic potential has generated much excitement, with growing evidence of its remarkable benefits in depression, as well as a number of other psychiatric disorders. However, despite promising clinical data, our understanding of psilocybin's therapeutic mechanisms remains limited. The lack of mechanistic studies appears to be due in part to the assumption that psilocybin's agonism at serotonin receptors in the brain, known to be responsible for the drug's psychedelic effects, also explains its various therapeutic benefits, although several recent studies suggest that other mechanisms are probably involved. The microbiome-gut-brain axis, which is increasingly recognized as a driver of behavior and modulator of psychotropic drug action, is a plausible but largely unexplored target for psilocybin. Here we begin to examine the effects of psilocybin on behavior, gut microbiota, and dependence on psilocybin-induced changes in 5HT2A and 5HT2C receptors.

Methods:In the first study, adult male and female C57BL/6J mice were exposed to a single dose of saline, psilocybin, ketanserin, a 5HT2A and 5HT2C receptor antagonist, or psilocybin in combination with ketanserin. The head twitch response, a validated behavioral measure of central 5HT2A receptor agonism, was measured 30 minutes after treatment. Increased plus maze, social interaction and forced swimming behavior were measured between 3 and 6 days after treatment. In a second cohort, male mice were again treated with saline, psilocybin, ketanserin, or psilocybin plus ketanserin. Then, 3 days after treatment, behavior was assessed and gut contents were collected for 16S rRNA sequencing to determine bacterial composition and diversity. Finally, intestinal contents were collected from mice treated with saline or psilocybin and then administered by gavage to untreated male mice, followed by behavioral analysis.

Results:Psilocybin induced a strong head twitch response, increased exploratory behavior in the elevated plus maze, increased social behavior in the social interaction test, and decreased immobility in the forced swimming test. Co-administration of ketanserin completely blocked the head twitch response without significantly altering the effects of psilocybin on other behavioral outcomes. In a separate cohort, psilocybin treatment led to a major change in the gut microbiome, with particularly pronounced changes in the colon that were only partially blocked by ketanserin pretreatment. Finally, transplantation of intestinal contents from psilocybin-treated mice into naive mice resulted in behavioral changes consistent with the effects of psilocybin treatment.

Conclusions:Our results show that a single dose of psilocybin elicits behavioral changes in mice relevant to studies of resilience and mood disorders. Our results further indicate that behavioral changes may not depend entirely on psilocybin agonism of 5HT2A and 5HT2C receptors. Furthermore, psilocybin appears to largely alter the gut microbiome, and transplantation of gut contents replicates the behavioral change associated with psilocybin treatment, suggesting a previously unknown microbiome-gut-brain mechanism of action.

Key words:Psilocybin, gut microbiome, mood and anxiety disorders, translational animal models

Disclosure:Nothing to disclose.

Masayuki Taniguchi, Kazutoshi Matsushita, Rei Mishima, Mitsutaka Kadota, Shigehiro Kuraku, Tomoyuki Furuyashiki*

Kobe University School of Medicine, Kobe, Japan

Background:Clinical studies have suggested the presence of neuroinflammation in depressed patients. Rodent studies have shown that chronic stress activates microglia, leading to depression-related behaviors through the induction of pro-inflammatory molecules. Microglia appear to use distinct but overlapping molecules in various areas of the brain to cause behavioral disturbances. However, histological markers for microglial activation can only capture a limited facet of microglial responses. Therefore, microglial responses to chronic stress and their functions remain poorly understood.

Methods:We have exposed male C57BL/6 N mice to the acute or chronic stress of social defeats. We divided mice after chronic stress of social defeat into susceptible and resistant mice based on the level of social avoidance, a typical behavior related to depression. We then isolated microglia from various brain areas of these mice, including the medial prefrontal cortex (mPFC), primary motor and sensory cortex, hippocampus, nucleus accumbens (NAc), and hypothalamus, and subjected these cells to RNA Single Cell Seq . 🇧🇷 In addition, we further analyzed the microglial transcriptome of mPFC and NAc, two representative brain areas with distinct social defeat stress responses, using bulk RNA sequences. We then predicted the transcription factors responsible for stress-induced changes in the microglial transcriptome and investigated their functional importance through genetic and surgical manipulations.

Results:Using RNA-seq of a single microglial cell isolated from multiple brain regions in mice, we found that microglial transcriptomes showed brain region specificity and individual variability in stress susceptibility after chronic social stress. Further microglial transcriptome analysis of mPFC and NAc-secreted gene clusters of brain region-specific (local) and non-specific (global) responses to chronic social stress and global responses encoded individual variability in stress susceptibility. Epigenomic analyzes using H3K27ac ChIP-seq and ATAC-seq predicted distinct transcription factors involved in the respective responses, and surgical and genetic manipulations identified a peripheral stress signal that induced global transcriptional responses to transmit stress-prone microglia.

Conclusions:These results suggest that microglia integrate local and global stress signals through the transcriptional machinery to determine their state of activation and promote the pathology of mental illness.

Key words:Social Defeat Stress, Depression, Microglia, Neuroinflammation, Medial Prefrontal Cortex

Disclosure:Nothing to disclose.

Ebrahim Haroon*, Diana Beltran, Xiangchuan Chen, Evanthia Wommack, Blaine Roberts, Deqiang Qiu, Felicia Goldstein, Michael Treadway, Jennifer Felger, Andrew Miller

Emory University, Atlanta, Georgia, USA

Background:Depressed patients have a 2- to 5-fold increased risk of neurodegenerative diseases such as dementia (Alexopoulos, 2019; Byers & Yaffe, 2011). However, the predisposing risk factors that allow clinicians to stratify risk and initiate preventive measures are unclear. We propose that chronic inflammatory activation in depression promotes and perpetuates this risk. Our previous data have shown that increased inflammation in depression increases the risk of glutamate toxicity and leads to toxic disruption of neuronal systems related to emotional and cognitive functioning (Haroon et al., 2016). Here, we examined whether increased inflammation in the brain, as measured in cerebrospinal fluid (CSF), was associated with an increase in CSF neurodegeneration producers in depressives compared with controls.

Methods:Fifty-four subjects (35 depressed and 19 non-depressed controls) participated in the study and provided CSF samples and clinical and demographic information. Study participants were between 35 and 65 years old and did not use psychotropic drugs. No patient was discontinued from medication because of the study. CSF immunological markers were evaluated using previously described methods (Felger et al., 2020). CSF neurodegeneration markers were analyzed using the SIMOA assay on the Quanterix platform (Rissin et al., 2010). The panel of immunological markers included c-reactive protein (CRP), tumor necrosis factor (TNF), interleukin (IL)-6 and IL-1beta and its circulating receptors [TNF type 2 (TNFR2), IL-6 (IL6sr) and IL-1 receptor antagonist (IL1ra). The neurodegeneration panel included neurofilament light chain (NFL) protein, glial fibrillary acidic protein (GFAP), hyperphosphorylated tau-181 (tau), abeta-(ab)42, and ab40. The Ab42:40 ratio was used to distinguish neurodegenerative effects from immunological effects on amyloid metabolism. Extended regression analyzes were used to examine the relationship between CSF markers of immune degeneration and neurodegeneration between groups, accounting for subject characteristics as covariates, including age, sex, body mass index, vascular risk at 10 years, race and age. educational level. , marital and professional status. Additionally, the structural equation model (SEM) was used for mediation analysis.

Results:Of the inflammatory markers, CSF TNFR2 was differentially associated with markers of neurodegeneration depending on the state of the depressed group. Indeed, there was a significant CSF-TNFR2 interaction in the depressed group, which scored positively with CSF-NFL (cf=0.51, p=0.015), CSF-GFAP (cf=0.90, p<0.001), CSF- Tau (cf=0.50, p=0.013) is negatively associated with the CSF ab42:40 ratio (cf=-0.55, p=0.005). No TNFR2 CSF interactions per control group were significantly associated with markers of neurodegeneration. Mediation models showed that TNFR2 CSF indirectly mediated the negative effect of age on CSF Abeta42:40 (cf = -0.25, p = 0.014); and the positive effect of age on CSF Tau (cf=0.28, p=0.009), CSF GFAP (cf=0.22, p=0.02) and CSF NFL (cf=0.42, p<0.001) .

Conclusions:Our study is one of the first to simultaneously examine CSF markers for neuroinflammation and neurodegeneration in depressed and control subjects. We focused on depressed patients aged between 35 and 65 years due to the confluence of midlife and accumulation of neurodegenerative risk factors (Marsland et al., 2015). CSF elevations in TNFR2 were associated with elevations in markers of neurodegeneration in depressed subjects but not in controls. The profile of pro-inflammatory activity, which is exacerbated by the combined risk of aging and depression, may better predict the risk of neurodegeneration. Although gender was included as a covariate, this study was not designed to detect gender differences. The treatment of the risk of neurodegeneration in elderly depressed patients is of great interest. Treatment with immunomodulatory or neuroprotective agents, in addition to known antidepressants, may be helpful in this group.

Key words:Neuroinflammation, Neurodegeneration, Major Depression, Alzheimer's, Altersdepression

Disclosure:Nothing to disclose.

Evan Sitar*, James Sinacore, Angelos Halaris

Loyola University School of Medicine, Maywood, Illinois, USA

Background:Immune system activation and inflammatory response have become increasingly implicated in the pathophysiology of psychiatric disorders. It has been suggested that stress is associated with sustained activation of the innate immune system, leading to the release of pro-inflammatory cytokines in the nervous system (Haapakoski et al., 2015). Recent literature has identified a possible association between disturbances in the cytokine network and depression in bipolar disorder (Halaris et al., 2021). Increased expression of the pro-inflammatory cytokine IL-6 has been positively associated with patients' experience of depressive and anxious symptoms, particularly in bipolar depression (Muneer 2016), and has been postulated to increase symptom severity and the likelihood of response reflected in the treatment . Furthermore, specific single nucleotide polymorphisms (SNPs) have been shown to affect IL-6 expression and may predispose individuals to depression (Sundaresh et al., 2019). Understanding depressive illness in the context of stress-induced inflammation may help with intervention. For the present study, we hypothesized that depression in BD is accompanied by elevated blood levels of IL-6 and that this elevation is positively correlated with disease severity in BD. Finally, we predict that the addition of the cyclooxygenase-2 inhibitor and anti-inflammatory celecoxib (CBX), together with the selective serotonin reuptake inhibitor escitalopram (ESC), will reduce IL-6 blood levels and improve treatment outcomes. in patients with BD. with depression We also identified carriers of a specific SNP (rs4553185) in the BD study cohort and hypothesized that this SNP will affect IL-6 expression.

Methods:Data are from forty patients who completed a 10-week, randomized, double-blind, two-arm, placebo-controlled study evaluating the efficacy of CBX in combination with ESC in the treatment of TRBDD (Halaris et al., 2020). Both sexes were included. Patients were selected after meeting criteria for TRBDD, which included lack of remission within 8 weeks of two or more trials of adequate antidepressant treatment (Hidalgo-Mazzei et al., 2019). Subjects who met the criteria underwent a physical examination, medical history and laboratory tests, and completed several rating scales. Severity of depressive symptoms was assessed using the Hamilton Depression Rating Scale (HAM-D) and the Hamilton Anxiety Rating Scales (HAM-A), the Beck Depression Inventory, and the Hamilton Anxiety Inventory test. Beck at Baseline and Weeks 1, 2, 4, and 8 Patients with a HAM-D 17 score of 18 or greater were randomized and treated with CBX and ESC or ESC alone for 8 weeks. Blood samples were collected by venipuncture for IL-6 at baseline, week 4 and week 8. Patients were excluded for failing to meet the appointment schedule or having incomplete medical records. An independent sample t-test was used to compare IL-6 levels between TB patients and healthy controls. Depression and anxiety were extracted from rating scales, and Pearson's correlations and partial correlations were used to examine the relationship between scores and IL-6 levels. Comparison of IL-6 levels between the CBX+ESC and ESC treatment groups and in relation to treatment response or remission status was performed using analysis of covariance.

Results:There was a statistically significant difference (p = 0.007) between mean baseline IL-6 levels in the BD group (mean ± SD) (1.51 ± 1.30) (n = 43) and the healthy control group (0.94 ± 0.69) (n = 53). No clinical association was found between IL-6 levels and HAM-D, HAM-A or other scores. After controlling for baseline IL-6 by comparing the change in IL-6 levels from week 4 to week 8 and the difference in IL-6 levels at week 8, there was no statistically significant difference between BD patients treated with ESC (n=15) and TB patients treated with ESC and CBX (n=25). Treatment outcome was classified as treatment response if patients had a reduction in HAM-D 17 score of 50% or less or a score greater than baseline, and treatment remission if patients had a HAM score - D 17 ≤ 7. When TB patients were identified in terms of treatment outcome, adjusted mean IL-6 values ​​consistently decreased at week 8 (p = 0.074) when adjusting for non-responders (adjusted mean ± standard deviation) ( 1.65 ± 0.20) for treatment response (1.54 ± 0.25) and, finally, treatment outcome (1.06 ± 0.17). We also assessed SNP carrier status (rs4553185) and differentiated the cohort of TB patients into SNP carriers (n = 35) and non-carriers (n = 6). The results are presented on the poster.

Conclusions:Significantly elevated baseline blood levels of IL-6 in patients with TB suggest increased expression of pro-inflammatory cytokines in patients with depression. This finding supports the hypothesis that immune system dysregulation may play a role in depressive disorders. The observation that IL-6 levels declined at week 8 with better treatment outcomes suggests that IL-6 blood levels may have the potential to predict response to treatment. Although there was no correlation between IL-6 levels and the severity of depression or anxiety, nor was there a difference between IL-6 levels in any of the treatment groups, recruiting a larger sample size and increasing treatment duration may affect these results and emphasize the role that IL-6 plays in depression.

Key words:Bipolar Disorder, Treatment Resistance, Depression, Inflammation, Cytokine, Celecoxib, Escitalopram

Disclosure:Nothing to disclose.

Brandi Quintanilla*, Ashutosh Tripathi, Alona Bartosh, Peixiong Yuan, Dede Greenstein, Carlos Zarate, Anilkumar Pillai

University of Texas Health Science Center, Houston, Texas, USA

Background:More than 300 million people worldwide suffer from major depressive disorder (MDD). Unfortunately, only 30-40% of patients with MDD achieve remission after conventional monoamine antidepressant therapy. In recent years, ketamine has revolutionized the treatment of MDD, as its rapid antidepressant effects manifest themselves in a matter of hours, compared to weeks with traditional antidepressants. Many research efforts have attempted to identify ketamine's mechanism of action in mood disorders, with several studies suggesting a role for ketamine in the regulation of neuroinflammation. The complement system is an important component of the innate immune response that is critical to regenerative processes, including neurogenesis. The complement pathway has been implicated in the pathophysiology of depression, and studies have shown a significant increase in complement component 3 (C3) expression in the PFCs of suicidal depressed patients. Given the role of complement in depression, the ability of the ketamine/supplement to modulate glutamatergic transmission, and the history of research highlighting the anti-inflammatory properties of ketamine; There are reasons to suspect an overlap between the complement pathway and the mechanism of action of ketamine. To study this, we established elevations in baseline levels of the complement system, which are attenuated by administering ketamine at different times.

Methods:Thirty-nine people not taking MDD (23 F) and 25 healthy volunteers (HV, 16 F) participated in a randomized, double-blind trial comparing intravenous ketamine (0.5 mg/kg) with placebo. Blood was collected at baseline and at three time points after infusion (230 minutes, day 1 and day 3). Plasma was then aliquoted into cryovials and stored at -80°C until thawed for analysis. In this secondary analysis of a double-blind, placebo-controlled, in-hospital ketamine crossover study, C3a levels were determined by ELISA. Due to a noticeable bias in our data, we recorded transformed C3 values. We used a mixed linear model with C3 (log ng/ML) as the outcome and included drug fixed effects (KET, PBO) and drug*time to test our hypotheses. Models also included time as the main effect, gender, age, and baseline C3 as covariates, and one random intercept per subject.

Results:We found no overall drug difference or differences in C3a levels at any of the time points. The overall adjusted drug effect (collapsed over time) was (Ket - Pbo = -0.008 (SE = 0.04) t = -0.203 (df = 286), p = 0.84). The ketamine/placebo difference was 230 min at each time point: Ket - Pbo = -0.0517 (SE = 0.065) t = -0.795 (df=282), p = 0.4271; Day 1: Ket - Pbo = -0.0250 (SE = 0.0652), t = -0.384 (df = 279), p = 0.7014; and Day 3: Ket - Pbo 0.0531 (SE = 0.0695), t = 0.764 (df = 278), p = 0.4458.

Conclusions:Our results showed no significant effect of ketamine on plasma C3a levels. Additional analyzes on other complement proteins and their association with inflammatory markers are ongoing.

Key words:Treatment-resistant depression, ketamine, complement pathway

Disclosure:Nothing to disclose.

Qingqin Li*, Randall Morrison, Maggie Fedgchin, Vanina Popova, Wayne Drevets

Johnson and Johnson Pharmaceutical, Titusville, Nova Jersey, EUA

Background:Major depressive disorder (MDD) is an episodic disorder with a relapsing and remitting course. Neuroimmune mechanisms have been implicated in the pathophysiology of depressive symptoms in subgroups of patients with MDD. The current study examined the correlation between levels of immune-related proteins and the severity of depressive symptoms, and their association with future relapses/recurrence episodes.

Methods:Serum samples from participants with MDD were collected from one observational clinical trial OBSERVEMDD0001 (ClinicalTrials.gov identifier: NCT02489305, n=422) and three interventional clinical trials SUSTAIN-1 (NCT02493868, n=462), TRANSFORM-1 (NCT02417064, n = 320) and TRANSFORM-2 (NCT02418585, n = 420). Immune-related proteins were analyzed using the MRBM InflammationMap v1.0 protein panel, which consisted of 46 protein analytes. Samples from multiple time points were included in the analysis, which correlated protein levels with the severity of depression symptoms, as measured by the Montgomery Asberg Depression Rating Scale (MADRS). The protein analyte content was BoxCox transformed to approximate a normal distribution and protein analytes with a data loss rate >80% were removed from the analysis. Samples with the protein analyte below the lower limit of detection (LLOD) were prepared with missing data. A mixed linear model of adjustment for sample storage age, test batch (if applicable), subject age, gender, and symptom severity rating was fitted to assess the relationship between protein levels and the severity of depressive symptoms. .

Only the stable “baseline” samples of OBSERVEMDD0001 and SUSTAIN-1 were used for recurrence/recurrence analysis. For OBSERVEMDD0001, “baseline” samples were included in the analysis if participants were clinically stable (MADRS ≤14). For SUSTAIN-1, samples were collected from week 16 after patients achieved remission or stable response (MADRS ≤12) at the end of the optimization phase, but before randomization to continue treatment with esketamine plus antidepressant or switch to placebo most antidepressant uses the maintenance phase. In the OBSERVEMDD0001 study, subjects were followed for up to 2.8 years, during which time patients continued antidepressant treatment. Clinical assessments were performed at regular intervals to detect relapses/recurrences. Proteins associated with relapse/relapse in each study/treatment arm were analyzed separately. Meta-analyses by antidepressant type or illness population (treatment-resistant depression (TRD) and non-TRD) were also performed.

Results:~28 protein analytes were detectable in >80% of samples. Interleukin 12 p40 subunit (IL12p40) and MCP-1 were associated with MADRS symptom severity score in OBSERVEMDD0001 (β=-6.56×10-3, p=0.0001, adjusted p-value=0.003 for IL12p40 and β=2.38×10- 2, p=0.005, adjusted p-value=0.07 for MCP-1). The correlation of MCP-1 with the MADRS score was also demonstrated in the TRANSFORM-1 studies (β = 5.10 × 10-3, p = 0.03) and TRANSFORM-2 (β = 4.54 × 10-3, p = 0.06) observed. but not in SUSTAINABILIDADE-1. However, the IL12p40 finding in other studies was not significant.

For relapse analysis, stable “baseline” samples of 63 relapses and 154 non-relapses were retained for OBSERVEMDD0001. Nine proteins were nominally associated with relapse status at follow-up (p < 0.1). For SUSTAIN-1, samples from the esketamine arm (21 relapsed and 34 non-relapsed) and the placebo arm (33 relapsed and 48 non-relapsed) were retained in the analysis. Five proteins and 1 protein from the esketamine and placebo arms, respectively, were nominally associated with relapse status during the maintenance phase (p<0.1). Meta-analysis of the two studies (three separate analyses) found that monocyte chemotactic protein 1 (MCP-1) consistently predicted relapse status in all three analyzes (p=0.003, adjusted p-value=0.09) .

Conclusions:These results are remarkable given the evidence that chemokines play an important role in mediating interactions between immune cells in the periphery and those within the CNS. We provide evidence that higher MCP-1 levels are associated with lower depression symptom severity scores, consistent with a recent meta-analysis indicating that MCP-1 is elevated in depressed individuals compared to healthy controls. In addition, early MCP-1 is associated with the course of relapsing disease.

Key words:MDD, MCP-1/CCL2, relapse, depressive symptoms

Disclosure:Janssen Research and Development, LLC - Employee (self-employed), Johnson and Johnson - Stocks/Stocks (self-employed)

Elizabeth Blank, Steve Wu, Donald Gilbert, John Sweeney, Elizabeth Smith, Lauren Schmitt, Rebecca Shaffer, Meredith Will, Travis Larsh, Paul Horn, Kelli Dominick, Craig Erickson, Ernest Pedapati*

Cincinnati Children's Hospital, Cincinnati, Ohio, USA

Background:Major depressive disorder (MDD) disproportionately affects people with autism spectrum disorders (ASD). MDD is a leading cause of dysfunction, social isolation and suicide. Tragically, people with ASD are estimated to have a 4 times greater risk of developing MDD and 9 times greater risk of committing suicide. Despite this urgent need, intervention research specifically targeting MDD in ASD is sparse. No drug studies have focused on MDD in ASD. Standard medications for mood disorders, such as selective serotonin reuptake inhibitors, can be unpredictable or ineffective in people with ASD. Repetitive transcranial magnetic stimulation (TMS) is an effective non-pharmaceutical treatment for MDD with strong support from meta-analyses involving over 1,000 patients from randomized clinical trials (RCTs) and is covered by most insurers. However, repetitive TMS therapy involves 40-minute high-intensity pulse sessions over a period of 4 to 6 weeks. Lack of evidence on ASD, duration of therapy, and sensory concerns have severely limited the use and scalability of TMS in the ASD population. The study team is highly experienced in the use of TMS and tested an innovative, low-intensity, accelerated TMS protocol that is ideal for MDD in people with ASD.

Methods:This is an interim analysis of an ongoing intervention study of accelerated theta burst stimulation (aTBS) in MDD in ASD (see NCT05271357). The primary outcome was the Hamilton Depression Rating Scale (17 points; HDRS) and the secondary outcome was the NIH Cognitive Toolkit. The research results concerned EEG connectivity. The study design is a randomized active comparative trial of unilateral or bilateral aTBS stimulation of the dorsolateral prefrontal cortex (DLPFC) (including mandatory entry controls and two-week waiting list). ATBS sessions are given three times a day for ten days (30 sessions). The intervention was performed with a Magstim Horizon (Magstim/EGI, Whitland, UK) with a 70 mm figure-of-eight EZ cold coil. Resting motor threshold was determined using single-pulse TMS and electromyography. Theta burst stimulation: Participants received intermittent theta burst stimulation (50 Hz in 5 Hz bursts) for a total of 600 pulses at 90% RMT for each session. We use the Beam F3 location method. EEG recordings are acquired using a Netamp 400 amplifier (MagstimEGI, Eugene, OR) and 128-channel Hydrocel networks in anechoic booths. We perform source estimation with Brainstorm to compute the depth-weighted source model and L2 norm to estimate the minimum norm to create a current source density (CSD) map to reconstruct time series activations. Standard weighted alpha phase delay index connectivity measures from the right anterior cingulate cortex to the left prefrontal cortex were estimated for each subject. Statistics: As this is an intermediate analysis, we examined the effect of aTBS (unilateral and bilateral) on outcome measures. For our primary endpoint, we assessed the change in HDRS from baseline immediately and 4 weeks after treatment using FDR-corrected paired t-tests. Secondary variables were compared using t-tests. The relationship between changes in frontocingular connectivity and changes in HDRS score was examined using Pearson's correlation.

Results:The following analysis reflects the seven subjects who completed aTBS treatment and had at least one 4-week follow-up visit at the time of abstract submission. In November 2021, we evaluated 14 subjects (2 females), two subjects on the waiting list, one subject scheduled for treatment, and one subject who withdrew prior to treatment. Our pilot demographics are 57% Caucasian and 14% African American, Hispanic and Asian. Primary endpoint: The mean HDRS value at baseline (M = 20.3, SD = 3.5) was significantly reduced immediately after treatment (M = 7.0, SD = 2.8, t = 10.5 , FDR p = 4.4 × 10-5, Cohen's d = 3.9 , n. a = 7) and persistent at week 4 (M = 5.4; SD = 2.7; t = 9.7, FDR p = 6.9 × 10-5, Cohen's d = 3.7, n = 7). Secondary outcome: Baseline fluid cognition composite score (M = 43.1, SD = 4.7) significantly improved at week 4 after aTBS intervention (M = 51.4, SD = 6.6; t = - 3.1, p = 0.02, Cohen's d = 1.18, n = 7). Exploratory: EEG source analysis was only available in five subjects at the time of abstracting. Decreased prefrontal connectivity to the cingulate after aTBS was predictive of an improved HDRS score (R = 0.82, p = 0.09, n = 5).

Conclusions:We present early but promising results from the use of accelerated TBS in a diverse sample of people with ASD and MDD. We observed significant improvement in MDD symptoms leading to remission, but also improvements in objectively measured fluid perception. We identified a potential neural biomarker suggesting that left prefrontal (stimulation site) and cingulate connectivity is associated with symptoms of depression. The availability of a 10-day non-pharmaceutical intervention for the rapid remission of MDD would have major implications. The negative consequences of MDD are particularly devastating, compounded by the lack of evidence-based treatments and atypical responses in ASA. An optimized TMS protocol for MDD in ASD that can be used with commercially available TMS devices would greatly improve access to care, reduce the need for specialists, and allow for rapid recovery as an intermediate option between medication and ECT.

Key words:Autism and Depression, Transcranial Theta Burst Magnetic Stimulation, Electroencephalography

Disclosure:Nothing to disclose.

Camila Cosmo*, Amin Zandvakili, Thaise Toutain, José García Vivas Miranda, Noah Philip

Brown University, Center for Neurorestoration and Neurotechnology, Providence VA Medical Center, Providence, Rhode Island, EUA

Background:Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that uses magnetic pulses to generate electrical current in the cortex, thereby modifying brain networks. Several studies have demonstrated the efficacy of rTMS in neuropsychiatric disorders, including drug-resistant depression. However, these previous studies mainly showed therapeutic and neurophysiological effects after long-term treatment. The identification of brain biomarkers for early therapeutic response remains a major unanswered question in this field. Here we used a new graph-based analysis method called Functional Cortical Networks (FCN) to examine electroencephalogram (EEG) data, hypothesizing that changes would occur at the start of rTMS treatment.

Methods:Resting EEG activity was measured in fifteen patients with drug-resistant depression after five sessions of rTMS (5 Hz, 120% MT, 3000 counts/session, left dorsolateral prefrontal cortex). Ten minutes with eyes closed; The 64-lead EEG was recorded at baseline (pre-treatment; T0) and after five sessions of rTMS (T1). An FCN model was built applying time-varying graphs and motif synchronization. Each EEG electrode position was identified as a node, and the synchronization between the electrodes is called an edge. The main result was the degree of the weighted node; this parameter indicates how often the nodes (ie the EEG electrodes) were synchronized during the EEG acquisition period. Analyzes were performed using the EEGLAB/MATLAB software system (Mathworks, Inc.).

Results:A paired t-test showed a significant acute effect of rTMS on the left posterior region with an increase in weighted nodule grade of 37.825 after five sessions of rTMS (95% CI, 468 to 75.181); and marginally significant in the left frontal region (95% CI, -1,663 to 111,981). No other significant changes were observed when analyzing additional hemispheres and regions (p ≥ 0.05).

Conclusions:FCN models can serve as a sensitive measure of acute changes in neural mechanisms underlying therapeutic rTMS, as these pilot results demonstrate. Five sessions of rTMS were enough to obtain greater synchronization between the posterior and anterior left electrodes, with a statistically significant increase in the former. Our data are consistent with previous studies that showed that increased left frontal activity may be related to decreased negative affect, while increased central and posterior activity likely reflects increased arousal implied in reduced fatigue and increased motivation. Based on our findings, FCN models may contribute to a better understanding of the acute mechanisms underlying rTMS treatments. A future review will examine whether early EEG changes can serve as a potential predictor of therapeutic response to rTMS.

Key words:Repetitive transcranial magnetic stimulation (rTMS), functional brain network, treatment-resistant depression, non-invasive neuromodulation

Disclosure:Nothing to disclose.

Sidney Kennedy*, Peter Giacobbe, Sakina Rizvi, Amanda Ceniti, Rima Styra, Andrew Lozano

Hospital St. Michael's, Toronto, Canada

Background:Deep brain stimulation (DBS) of the subcallosal cingulate white matter (SCG) has been evaluated in treatment-resistant depression (TRD) with mixed results. Despite a large number of positive findings in open studies, randomized controlled trials (RCTs) have not yet supported these results. The primary objective of this study was to compare the effectiveness of active versus sham DBS stimulation with SCG in reducing depressive symptoms during a 6-month randomized, double-blind period, followed by an open-label outcome evaluation for an additional 18 months. 🇧🇷

Methods:Thirty-three male and female patients with TRD were enrolled in this randomized, placebo-controlled, double-blind, crossover study between 2010 and 2016 at Toronto Western Hospital, University of Toronto. Participants had a current major depressive episode lasting more than 12 months and documented resistance to at least 4 appropriate depression treatments from at least 3 treatment categories in the current episode. Thirty-one of these patients subsequently underwent DBS implantation. Using a Balaam crossover design, participants were randomized to one of four stimulation sequences: ON-ON, ON-OFF, OFF-ON, or OFF-OFF during two consecutive three-month treatment periods. The primary endpoint of the RCT was change in the Hamilton Depression Rating Scale (HDRS-17) from baseline at 3 and 6 months, with a 5-point reduction representing a minimal clinically significant difference. Response rate was calculated as a ≥50% reduction in HDRS-17 score from baseline. At the end of the 6-month randomized phase, all participants received active stimulation in an open-label extension phase for an additional 18 months.

Results:No statistically significant treatment effect was observed in the double-blind phase, either for intention-to-treat analysis (p=0.4725) or for analysis according to treatment (p=0.7397) using a linear random effects model . All four treatment groups showed a reduction in HDRS-17 scores at 3 and 6 months, but this did not differ significantly by state of stimulation. No deaths or unexpected side effects from the device have been reported. In the subsequent open-label extension phase, significant reductions in HDRS-17 scores were observed from baseline to 12, 18, and 24 months after implantation (all p<0.0001) across the entire sample. Response rates at 12, 18, and 24 months were 64.5%, 63.6%, and 71.0%, respectively. Significant and progressive improvements in functional impairment, as measured by the Sheehan Disability Scale, were also observed at 12 months (p=0.002), 18 months (p=0.0003) and 24 months (p<0.0001) after the implant.

Conclusions:The double-blind RCT phase could not show any statistically significant difference between active and sham stimulation. In the open-label phase, most participants responded to DBS, a particularly notable finding in this TRD population. There are several possible explanations for these results: First, Balaam's crossover design may have resulted in insufficient duration to see a treatment effect. Second, this design resulted in a reduced sample size for each treatment condition. Third, the improvements seen with sham stimulation could be due to the effects of the microlesion (insertion) or, ultimately, to frequent visits to the study psychiatrist. This study also supports the safety of DBS versus SCG for TRD, with reported side effects consistent with those previously reported in DBS studies.

Key words:Deep brain stimulation, treatment-resistant depression, randomized Balaam crossover design, open-label follow-up

Disclosure:Abbvie: consultant (himself), Boehringer-Ingelheim: advisory board (himself), Janssen: consultant (himself), Janssen: contract research (himself), Lundbeck: consultant (himself), Lundbeck: research contractor (himself) himself), Lundbeck Institute: consultant (himself), Merck: consultant (himself), Otsuka: other financial or material support (himself), Otsuka: consultant (himself), Pfizer: contract research (himself), Sunovion : consultant (himself), Dienst: consultant (himself). ), Brain Canada: Grant (automatic), CIHR: Grant (automatic), Ontario Brain Institute: Grant (automatic), Strategy for Patient Oriented Research (SPOR): Grant (automatic), Field Trip Health: Stock / Equity (automatic) , Abbott: Other financial or material support (car)

Andrew Fukuda*, Lauren Hindley, Eric Tirrell, Linda Carpenter

Brown University, Butler Hospital, Providence, Rhode Island, EUA

Background:Transcranial magnetic stimulation (TMS) is effective in major depressive disorder (MDD), but the therapeutic mechanism of action is not fully understood and no biomarkers are used to inform clinicians and patients about the likelihood of a favorable clinical outcome. Astrocytes play a role in the pathophysiology of depression but have not been studied in TMS. Calcium-binding protein S100 (S100B) is ubiquitously and selectively expressed in astrocytes and plays a variety of roles, including neuroplasticity and neuroinflammation, and has been shown to be elevated in the serum of depressed patients compared to non-depressed controls and is a promising clinician. Biomarkers in TMS. We provide preliminary data showing the association between peripheral levels of S100B and clinical outcome.

Methods:A prospective observational study was performed in a TMS outpatient clinic with consenting patients, consisting of a collection of behavioral and serum measurements before and after treatment with TMS (standard clinical treatment targeting the left DLPFC daily for 6 weeks). The Depressive Symptom Inventory (IDS-SR) as a measure of overall severity of depressive symptoms. An enzyme-linked immunosorbent assay (ELISA) was performed with serum for S100B. A general linear repeated measures (GLM) model was performed to determine whether the change in S100B concentration between those who achieved and those who did not achieve clinical remission varied over time (pre vs. post) significantly different as a factor within of individuals. remission vs. non-remission) as a factor among subjects with gender and age as covariates. Binary logistic regression was performed to determine the effects of age, gender, baseline depression, and baseline S100B concentration on the likelihood of participants achieving remission.

Results:66 patients (26 men, 44 women) had pre and post IDS-SR and S100B levels. The remission rate was 44%. GLM did not show a statistically significant effect observed over time, but there was a statistically significant difference between senders and non-senders (F = 4.641, p < 0.05), as indicated by a t post hoc test that senders had a higher S100B concentration • lower at baseline (p < 0.05, Cohen's d = 1.213) and after treatment (p < 0.05, d = 0.445) compared with non-remitters. The logistic regression model was statistically significant, χ2(4)=11.031, p < .05. The model explained 20.6% (Nagelkerke R2) of the variance in achieving clinical remission and correctly classified 65.2% of cases. Lower concentration of S100B before the treatment cycle was associated with a greater likelihood of achieving remission.

Conclusions:Although S100B did not show any significant change with TMS treatment, those who achieved clinical remission had lower concentrations compared to those who did not achieve remission at both time points. Furthermore, lower baseline levels of S100B were associated with a greater chance of achieving clinical remission and showed promise as a predictive biomarker of clinical outcome. Studies are currently underway to analyze specific symptom domains that S100B may be associated with in depression.

Key words:Astrocytes, biomarkers, repetitive transcranial magnetic stimulation (rTMS), natural environment, treatment-resistant depression

Disclosure:Nothing to disclose.

Rebecca Strafella, Reza Zomorrodi, Jennifer Lissemore, Yoshihiro Noda, Zafiris Daskalakis, Daniel M. Blumberger, Daphne Voineskos*

Centre for Addiction and Mental Health, Toronto, Canadá

Background:Intermittent L-DLPFC theta burst stimulation (iTBS) is effective in treatment-resistant depression (TRD). We indexed markers of transcranial magnetic stimulation-electroencephalography (TMS-EEG), N45 and N100 amplitudes, and global TMS-evoked activity (GMFA-AUC) at baseline and after iTBS, and compared separate and contiguous iTBS regimens. TMS-EEG markers were also compared between iTBS responders and non-responders.

Methods:TMS-EEG was analyzed from a triple-blind, randomized 1:1 trial for TRD that compared a separate (54-minute interval) and contiguous (0-minute interval) iTBS program with 2 × 600 pulses for 30 treatments. Participants underwent TMS-EEG for L-DLPFC at baseline and after treatment. 114 participants had a usable TMS-EEG at baseline and 98 after treatment. TMS evoked potential (TEP) components (N45, N100) were examined using global mean field analysis.

Results:N100 amplitude decreased from baseline to post-treatment regardless of treatment group (F(1, 106.02 = 5.20, p = 0.02). In both groups there was no change in N45 amplitude 11.30 , p=0.001, pcorrected=0.0004) scores (F(4, 106)=6.28, p=0.00014).

Conclusions:These results add to the evidence for an association between the neurophysiological effects of iTBS and treatment efficacy in TRD in the largest pre/post rTMS-TMS-EEG sample collected to date. Future studies are needed to consolidate the predictive potential of clinical applications of TMS-EEG markers.

Key words:Theta-Burst-Stimulation, TMS-EEG, behandlungsresistente Depressão

Disclosure:Nothing to disclose.

Akila Weerasekera, Eva Ratai, Jacek Dmochowski, Katherine A. Collins, Aura M. Hurtado, Luis De Taboada, Maia B. Gersten, Julie A. Clancy, Matthew J. Hoptman, Molly K. Irvin, Allison Sparpana, Elizabeth Sullivan, Xiaotong Song, Arwa Adib, Paolo Cassano*, Dan V. Iosifescu

Massachusetts General Hospital, Boston, Massachusetts, USA

Background:Transcranial photobiomodulation (t-PBM) with near-infrared light (NIR) penetrates the cerebral cortex and is captured by the mitochondrial enzyme cytochrome c oxidase (CCO), thus stimulating the mitochondrial respiratory chain. t-PBM also significantly increases cerebral blood flow (CBF) and oxygenation. Smaller studies have reported that t-PBM may be an effective treatment for major depressive disorder (MDD). However, t-PBM can affect brain temperature and these effects are unclear. Therefore, possible overheating of the brain during t-PBM is concerning and should be investigated. In this pilot study, we evaluated the dose-dependent effects of t-PBM on brain temperature in patients with MDD.

Methods:We enrolled 30 adult subjects (aged 18-65 years) who met DSM-5 criteria for MDD, non-refractory (0 to 2 antidepressant failures in the current episode), not medicated or on stable doses of antidepressants, without other significant medical complications. problems. or psychiatric comorbidities. All subjects underwent three sessions of t-PBM with different doses (maximum irradiation; low: 50, medium: 300, high: 850 mW/cm2, low and medium doses were delivered in continuous wave [CW] mode, high-dose pulsed wave [PW mode]) and sham treatment. 1H-MRS data: Single-voxel (SV)-MRS was performed with a PRESS sequence (TE/TR = 30 ms/2 s, moving averages = 32 x 4) using a Siemens Trio 3T MRI scanner. A voxel with a volume of 30 mm × 30 mm × 15 mm was placed in the left prefrontal region. Brain temperature (°C) was determined by analyzing the chemical shift differences of the 1H-MRS spectrum between the water (~4.7 ppm) and NAA (~2.01 ppm) peaks using the HLSVD method of jMRUI software and the formula obtained by Zhu et al.: Brain (°C) = 36 - [103.8 × (ΔH2O − NAA - 2.6759)].

Results:After the QC procedures, the following group numbers were available for pre- and post-temperature estimates: False (n=10), Low (n=11), Medium (n=10), High (n=8). We found no significant post-irradiation temperature differences between the active or sham tPBM groups (unpaired t-test; p-value range 0.105-0.781). We also tested possible differences in pre-post brain temperature variability in each group. Regarding the active groups of t-PBM; the smallest fluctuation (variance) was observed for the medium dose (σ2 = 0.29), then for the low dose (σ2 = 0.47) and the largest fluctuation for the high dose (σ2 = 0.67). The simulated condition showed the lowest overall variation (σ2 = 0.11).

Conclusions:In general, the results of our MRS thermometer indicate that no significant elevations in brain temperature occur during the t-PBM application procedure. The fluctuations in brain temperature observed before and after the t-PBM sessions were not statistically significant. The lowest temperature variation was observed at the medium dose, while the highest was at the high dose. These preliminary results indicate a favorable safety profile for t-PBM treatment with NIR in terms of brain temperature changes.

Key words:Neuromodulation, photobiomodulation, near infrared light, depression, MR spectroscopy

Disclosure:Niraxx Light Therapeutics Inc: Consejo asesor (auto), Niraxx Light Therapeutics Inc: Miembro de la junta (auto), Niraxx Light Therapeutics Inc: Consultor (auto), Niraxx Light Therapeutics Inc: Fundador (auto), Niraxx Light Therapeutics Inc: Acciones / Capital Social (Auto), Niraxx Light Therapeutics Inc: Patente (Auto)

Merage Ghane*, Simona Graur, Michele Bertocci, Henry Chase, Tyler Conrad, Alexander Skeba, Rachel Kaskie, Sabine Janssen, Lisa Bonar, Tyler J. Brady, Fabio Ferrarelli, Mary Phillips

University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Background:Recurrent hypo/manic episodes are a hallmark symptom of bipolar disorder (BD) and are associated with disruptive impulsivity, reward sensitivity, and sensation seeking. Existing treatments are associated with severe side effects and high rates of relapse, underscoring the need for more effective and mechanistically targeted treatments. Increased left ventrolateral prefrontal (vlPFC) and ventral striatal (VStr) activity during reward expectancy (RE) has been shown to be associated with the risk of hypo/mania and dysregulated affect states. Although non-invasive neuromodulation of subcortical structures is not yet fully possible, cortical targets such as B. the vlPFC, which have direct and indirect projections to subcortical circuits relevant to the ER. Our aim is to better understand the mechanistic role of vlPFC in ER-related activity, affect regulation and hypo/mania, in order to identify new targets for neuromodulatory interventions. To do this, we investigated how continuous inhibitory (c)TBS on the left vlPFC differentially affects ER-related activity and acute affect in BD and healthy adults compared to left somatosensory (control) and sham disease (18) . Years). We hypothesized that any of the three cTBS disorders would be associated with greater reductions in left vlPFC and left ventral striatum (vStr) and that change in activity would be associated with a change in affective state.

Methods:To date, 11 adults (73% female) have completed all fMRI sessions before and after TBS and assessed ER-related neural activities and effects using a probabilistic uncertain reward task (card guessing task). We used a priori set seeds in the left vlPFC and left vStr to test whether any of the three stimulation conditions (stimulation) showed a greater decrease in ER-related activity from pre-stimulation to post-stimulation. In addition, we used linear regression within the stimulation condition and tested whether the change in vlPFC and vStr activity represented a significant variation in the change in positive and negative affect from before to after stimulation. As these data are part of an ongoing clinical trial, group status and cTBS endpoints will be blinded to the end of the trial.

Results:Due to ongoing data collection, we focus primarily on effect size results to maintain best practices until they are significant enough for robust statistical testing. A cTBS state resulted in a greater decrease in ER-related left vlPFC (partial EtaSq = .11) and left vStr activity (partial EtaSq = .27) compared to the other cTBS states. For this condition alone, the change in left vlPFC activity, but not vStr, accounted for a significant portion of the negative (B=0.763, p=048) and positive (B=-0.657, p=0.01) variation. Change in vlPFC activity accounted for 29.9% of the variance (r2 = 0.299) of change in negative affect (after accounting for change in positive affect, full model r2 = 0.559) and 41.6% of the change in affect change positive (after accounting for negative affect change affect ) of modification, complete model r2 = .677).

Conclusions:The left vlPFC is a promising neural target for neuromodulatory intervention in adults with BD. Preliminary results provide a proof of concept and suggest that targeted cTBS reduces ER-related activity in both the left cortical vlPFC and the subcortical vStr. However, only reductions in ER-related activity in the vlPFC seem to contribute to the regulation of positive and negative affect. As data collection is ongoing, we plan to extend these methods to a larger sample and further test the causal role of vlPFC in hypo/mania-related symptoms and reward sensitivity. Future work should test the transdiagnostic relevance of this approach in disorders affected by affect dysregulation and/or increased focus motivation/impulsivity in general.

Key words:Theta burst stimulation, reward expectancy, affective instability, vlPFC, bipolar disorder, fMRI

Disclosure:Nothing to disclose.

Claire Leroy, Sebastien Goutal, Denis David, Wadad Saba, Maud Goislard, Michel Bottlaender, Fabien Caillé, Phi T Nguyen, Alain Gardier, Rene Hen, Emmanuelle Corruble, Romain Colle, Nicolas Tournier, Indira Mendez-David*

Paris-Saclay University, UVSQ, Center for Research in Epidemiology and Public Health (CESP), UMR 1018, CESP-Inserm, ORSAY, France

Background:The high prevalence of major depressive disorder (MDD) and the differential efficacy of antidepressants justify the investigation of molecular determinants of pathogenesis and therapy. Several studies have provided evidence of reduced synapse density and cell loss in rodent models of depression. Antidepressant therapies can rapidly induce synaptogenesis and reverse these neuronal deficits. It is now possible to estimate synaptic density in the living brain using positron emission tomography (PET) using new radiotracers that target synaptic vesicle glycoprotein 2A (SV2A). Lack of synaptic density has recently been demonstrated in a small number of patients with major depression. However, the effect of an antidepressant on synaptogenesis in the human brain has yet to be studied in vivo. This preclinical study aims to profile, via PET SV2A imaging, depression-like phenotype synaptic density and antidepressant responses in a well-validated mouse model based on glucocorticoid elevation.

Methods:Adult male C57BL/6JRj mice were subjected to chronic corticosterone treatment (CORT, 35 µg/ml) in drinking water to induce a depression-like phenotype. The mice then underwent 4 weeks of antidepressant treatment with selective serotonin reuptake inhibitors (SSRIs) (fluoxetine, 18 mg/kg/day) or vehicle (VEH). Synaptic density was compared between CORT-fluoxetine (N=6), CORT-HEV (N=6) and VEH-HEV (N=5) using 90 min PET acquisition after injection of [11 C]UCB -J ( 3.32 Mbq) compared ±1.43), an SV2A radioligand.

Depression score and antidepressant response were assessed by calculating latency to eat in the suppressed eating study before (after 4 weeks) and after (after 8 weeks) antidepressant treatment. The ratio of standardized uptake values ​​between 60-90 min of PET (rSUV) acquisition of [11C]UCB-J binding was extracted in the cortex and hippocampus and normalized to cardiac blood using Pmod.

Results:[11 C]UCB-J SUVr was decreased in the cortex and hippocampus of CORT-HEV mice compared to the EVH-VEH and CORT-fluoxetine group. [11 C]UCB-J-SUV in the CORT-fluoxetine and VEH-HEV groups were not significantly different. The chronic corticosterone-induced increase in depression score (CORT-VEH) was significantly reduced after 4 weeks of treatment with fluoxetine (CORT-fluoxetine mice) (p = 0.014), confirming efficacy similar to that of antidepressants. Interestingly, we observed an inverse correlation between depression score and [11 C]UCB-J SUVr in the cortex (p = 0.026).

Conclusions:This study suggests that the antidepressant effects of SSRIs may be related to presynaptic terminal repair. Synaptic plasticity may contribute to the neurobiological substrate of depression and be a target for controlling the effectiveness of therapy. Further investigations using an immunohistochemical study of synaptogenesis are currently underway to better characterize the biological significance of this change in [11 C]UCB-J binding.

Key words:Synaptogenesis, biomarkers, positron emission tomography (PET), depression, antidepressant

Disclosure:Scientific/Medical Advisory Board Member: Advisory Board (spouse)

Anna Van Meter*, Wei Guo, Sun Jung Kang, Kathleen Merikagas

NYU School of Medicine, New York, New York, United States

Background:Discharge from inpatient psychiatric care is generally based on an observed reduction in the patient's externalizing (eg, manic, psychotic) symptoms and/or resolution of safety concerns associated with suicidal ideation or homicide. However, given the high readmission rates, these readmission-to-discharge markers are flawed1. Other markers of patients' mental health, including sleep quality and activity patterns, may provide a more valid assessment of stability and readiness for discharge. Importantly, sleep and activity measurement can be performed using wearable devices and is not subject to the same biases as self-report (including motivation to fake well-being to go home).

We used a wrist actigraph, GENEActiv, to assess the stability and quality of sleep and physical activity in hospitalized adolescent patients during their hospital stay to determine whether there is an association between these metrics and post-discharge outcomes. We hypothesize that patients with disturbed sleep and/or inconsistent physical activity patterns would be more likely to have clinically significant symptoms one month after discharge than patients whose sleep and activity patterns are consistent. Furthermore, we assume that data collection with GENEactiv in the hospital environment is safe and feasible.

Methods:All new admissions to a juvenile hospital ward who were able to provide informed consent were invited to participate. Participants completed self-reports of depression (PHQ-9), mania (GBI-10M), and anxiety (GAD-7) at admission, discharge, and one month after discharge. Participants wore a GENEactiv during their hospitalization. Linear regression, controlling for age and self-reported gender (assessed separately from gender), tested associations between changes in symptoms (from baseline to discharge and from baseline to follow-up) with activity and sleep metrics based on actigrams during the hospitalization.

Results:There were 108 participants with valid Actigraph data. Mean age was 15.0 years (SD = 1.4), 80% were women. Higher mean activity during rest periods was associated with higher mean GAD (β=-1.99, p=0.007; β=-1.59, p=0.044) and PHQ (β=-3.25 , p<0.001; β). = - 2.05, p=) associated 0.030) values ​​at discharge or after care. Variability in activity during rest periods was also associated with less improvement in GAD (β=-2.82, p=0.002) and PHQ (β=-4.14, p<0.001) scores at discharge. Likewise, participants who woke up more frequently during the sleep phase had higher GAD scores at follow-up (β=-0.33, p=0.027), and variability in the number of nocturnal awakenings was associated with higher GAD (β= -0.65, p = 0.019) and PHQ (β = -0.92, p = 0.005) during discharge. Sleep duration variability was also associated with less improvement in PHQ (β=-2.44, p=0.018) from baseline to discharge. Participants with high variability in the difference in their activity levels across the day had less improvement in their PHQ scores (β=-39.91, p=0.029) from baseline to follow-up. Participants who were more sedentary showed less improvement in their GBI-10M scores at follow-up (β = -0.02, p = 0.030). No other variables were associated with changes in manic symptoms. Surprisingly, greater variability in sleep time onset was associated with improvement in GAD (β=2.32, p=0.027) and PHQ scores (β=6.40, p<0.001) from baseline to discharge . Only 13 participants required urgent care (ER or hospitalization) after discharge; This result was not associated with sleep or activity.

Conclusions:Nocturnal restlessness and wakefulness were associated with less improvement in depression and anxiety, both at discharge and at follow-up. Surprisingly, there was no significant association between manic symptoms and activity or sleep. The finding that sleep onset variability was associated with better outcomes may be related to circadian change (i.e., shift from all-night to nocturnal sleep) across the hospitalization rather than daily changes. Future research should assess whether patients' sleep/activity stabilization throughout their hospitalization, rather than means and standard deviations, is associated with outcomes. In this case, these metrics can help determine hospital patients' willingness to discharge due to internalized concerns.

Key words:Actigraphy, adolescent, psychiatric hospitalization

Disclosure:Nothing to disclose.

Reut Naim*, Shannon Shaughnessy, Ashley Smith, Sarah L. Karalunas, Katharina Kircanski, Melissa A. Brotman

National Institutes of Health, NIMH, Bethesda, Maryland, USA

Background:Emotional lability, or rapid and intense swings in affect, is associated with increased psychopathology and deterioration in adolescence. Although not a diagnostic criterion, emotional lability has been documented in depression, anxiety, and attention deficit hyperactivity disorder (ADHD) and is a transdiagnostic risk factor for general psychopathology. However, previous research has relied primarily on retrospective reports focused on compensated negative emotions and has yet to include participants with disruptive mood dysregulation disorder (DMDD), a diagnosis that manifests as emotional lability. The present study uses real-time ecological moment assessment (EMA) to examine naturally occurring aberrant changes in affective states in a pediatric transdiagnostic sample. This is the first EMA study to include participants with DMDD and also examine swings in negative and positive affect. We had two main objectives. First, we wanted to compare emotional lability between different diagnostic groups. We hypothesize that youth with psychopathology exhibit increased levels of emotional lability compared to healthy voluntary (HV) children. We also hypothesized that participants with DMDD and ADHD would experience greater emotional lability than participants with anxiety disorders (ANX), since emotional lability is an inherent aspect of these disorders. Our second objective was to compare positive and negative instantaneous affective oscillations between diagnostic groups. Based on previous literature, we hypothesized that patients would exhibit more diurnal affective fluctuations compared to HV participants. We wanted to exploratively test whether negative and positive fluctuations are associated with functional limitations across the various diagnostic groups.

Methods:130 participants (M = 12.55 years, SD = 2.51 years, 70% male, 65.40% white/Caucasian) with a primary diagnosis of DMDD, ADHD, ANX or HV completed a previously validated 1-week EMA protocol for irritability (Naim et al., 2021). Participants rated mood swings and mood symptoms three times a day for one week. Items of interest included ratings of positive affect, particularly transient happiness and dizziness, and negative affect, particularly transient fear, anger, and unhappiness. A composite score was generated for each positive and negative component of emotional lability using an unweighted average of all items in each category. Prior to assembly, we assessed the between- and between-person reliability of the EMA items using multilevel confirming factor analysis (MCFA), which revealed moderate to high overall reliability (range: 0.41-0.89). To capture variations in affective states within an individual over time, a calculation of successive mean squared difference (RMSSD) scores was applied to these composite scores. ANOVAs were performed to compare affective variances between diagnostic groups, and linear regressions were performed to assess their association with functional impairment assessed using a physician-reported measure (Clinical Global Impression Severity Scale, CGI-S).

Results:The rate of adherence to the EMA protocol was high (M = 78.54%, SD = 16.38%), all groups had a similar rate. As expected, differences in emotional lability were found between diagnostic groups, with clinical groups having a higher level of emotional lability compared to HV (all βs>0.34, ps<0.046). Within the patient groups, adolescents with DMDD showed the most unstable and fluctuating negative and positive affect (βs>0.41, ps<0.049). Emotional lability was associated with global deterioration across the entire sample (βs>0.11, ps<0.015).

Conclusions:The results demonstrate that emotional lability is a prominent and important mechanism to understand in the context of childhood mood disorders, especially DMDD. The results also demonstrate that aberrant swings in positive affect may be as important as aberrant swings in negative affect, and both are associated with adolescent psychopathology. Furthermore, this study supports the additional benefits of using real-time in vivo measurements to complement classic retrospective clinical assessments by parents/children or clinicians. Targeting labile humor in vivo could also be a potential treatment for DMDD, which is of crucial importance as few treatments have been developed for the disorder. As our sample largely consisted of white/Caucasian males, future work should increase sample diversity to further explore generalizability.

Key words:Emotional Dysregulation, Mood Disorders, Current Ecological Assessment, Adolescence, Pediatrics

Disclosure:Nothing to disclose.

Adina Fischer, Scott Fleming, Kelsey Hagan*, Bailey Holt-Gosselin, Alan Schatzberg, Leanne Williams

Columbia University Irving Medical Center, New York, New York, USA

Background:Less than half of patients with major depressive disorder (MDD) experience remission of symptoms since the first attempt with antidepressant medication (ADM). There are limited empirical data to guide ROM selection for an individual patient. As such, clinicians rely on trial and error and evidence of what works for the average patient when treating MDD with first-line ADM, resulting in persistent symptoms and increased morbidity and mortality for those who do not refer. Using state-of-the-art machine learning methods, we developed a model that identifies patient-specific first-line ROM predictors of likelihood of remission (and non-remission).

Methods:Recursive feature elimination was used to develop a sparse gradient-based decision tree model (25 features) that predicted binary remission (yes/no) of ADM. Features included pretreatment clinical, demographic, cognitive, and behavioral variables that were paralleled by participants (N = 1008) during the first visit of the International Study to Predict Optimum Treatment in Depression (iSPOT-D): A Randomized Trial, Model-Based, open-label, 8-week, longitudinal, repeated measures study evaluating response to three commonly prescribed first-line ADMs (sertraline, escitalopram, venlafaxine). Remission was defined as a 17-item Hamilton Rating Scale for Depression (HDRS) score of <7 at 12-week follow-up. The models were evaluated based on their accuracy and AUROC in predicting remission in a retained test set, using only measurements collected at baseline. Shapley scores were used to determine which variables most affected model estimates at the group and individual (patient) levels.

Results:The trained model performed significantly better than chance on an extended test set (AUROC = 0.64, 95% CI = 0.55 to 0.71, p < 0.001; precision = 0.63, 95% CI = 0.56 to 0.70, p = 0.010). Of the participants in whom our model showed a high risk of non-remission (ie, <20% predicted probability of remission), the model accuracy was 0.71. Traits identified by recursive feature deletion as having the greatest predictive value include pretreatment measures: severity of depression symptoms, severity of anxiety symptoms, impaired cognitive function (verbal memory and information processing speed), impaired identification of facial emotions (fear and disgust) and agitation (face and motor skills). This model was compared to models using common linear modeling approaches with the same number of features (25). Regularizing the elastic mesh resulted in lower performance on the test set compared to our approach (AUROC =0.59, precision =0.55), as did using later simpler models like canonical logistic regression (AUROC =0.54, precision = 0.55) and logistic regression with elastic network regularization (AUROC = 0.59, precision = 0.61).

Conclusions:Using sophisticated machine learning methods, we developed a model that identified patient-specific predictors of the likelihood of first-line ADM remission, which could have strong clinical implications if implemented in psychiatric outpatient or primary care settings. Furthermore, the results illustrate the advantage of using sophisticated machine learning models (gradient-based decision trees) over simple logistic regression, as this method has improved model accuracy and interpretability. The results show how variables derived from standard clinical assessments can be subjected to machine learning models to help develop personalized treatment plans, thereby optimizing outcomes and reducing morbidity and mortality in patients with MDD.

Key words:Antidepressants, major depressive disorder (MDD), machine learning, prediction, remission

Disclosure:Nothing to disclose.

Casco Karim*, Ahmad Mayeli, Francesco Donati, Brian Coffman, Daniel M. Blumberger, Noah Philip, Mary Phillips, Carmen Andreescu, Rebecca Price, Fabio Ferrarelli

University of Pittsburgh Western Psychiatric Institute and Clinic, Pittsburgh, Pensilvânia, EUA

Background:Transcranial magnetic stimulation (TMS) is used to treat several neuropsychiatric disorders, but results remain variable. Motor threshold (MT) is used to standardize doses, but does not consider structural variability in other cortical areas such as the dorsolateral prefrontal cortex (DLPFC) or orbitofrontal cortex (OFC). Electric field modeling can help estimate these differences. Our aim was to compare motor cortex, DLPFC, and OFC-E fields in MT and 120% MT, which is the standard dose in most TMS studies.

Methods:We collected T1-weighted and MT images from patients with OCD (n = 53) and healthy controls (n = 12). We estimate the E fields in the motor cortex, DLPFC and OFC at 100% and 120% MT, respectively. Two-way separate repeated measures ANOVAs were performed using post hoc t-tests.

Results:In the compulsive behavior sample, E fields in MT in the motor cortex and DLPFC were not statistically different, but larger than OFC. Motor cortex E fields at MT were smaller than DLPFC E fields at 120% MT, but were not statistically different compared to OFC E fields at 120% MT. A similar pattern was identified in the controls.

Conclusions:MT may not be an effective standard for dosimetry in TMS with variable dosage depending on the region of interest. Electron field modeling can be used to deliver similar TMS doses between participants or to adjust for differences in dosing, allowing for customized TMS treatments.

Key words:TMS, electric field modeling, depression, neuromodulation, OCD

Disclosure:Nothing to disclose.

Agustín Yip*, Savannah Layfield, Lucie Duffy, Samantha Wong, Joann Chen, Abdirahman Osman, Fernando Rodriguez-Villa, Steven Gelda, Eliot Gelwan, Philippe Beauchamp, Habiballah Rahimi Eichi, Joshua Salvi, Justin T. Baker, Alisa Busch, Jane Eisen , Kerry Resler

Hospital McLean, Belmont, Massachusetts, EUA

Background:There is growing recognition that 'continuous telemetry' and 'deep phenotyping' need to be integrated into routine mental health care to generate real-world evidence and objective quantitative measures of comparative effectiveness and to assess the heterogeneity of interventions. Here we report the first case, to our knowledge, of the simultaneous implementation of electronic health records (EHRs), patient-reported outcome measures (PROMs), actigraphy, instantaneous ecological assessments (EMAs) and biomarkers, and collection of inpatient genomic data individuals for depression. / Suicide and anxiety in a university psychiatric ward.

Methods:Participants admitted to McLean Hospital inpatient psychiatric units for depression and anxiety completed a series of self-assessments (depression: QIDS-SR-16, anxiety: GAD-7, performance status: BASIS-24) and screening instruments (disorder borderline personality [BPD]: MSI-BPD, Post Traumatic Stress Disorder [PTSD]: PCL-5, Substance Use: DAST-10, Alcohol Use: AUDIT) within 48 hours of admission and within 24 hours after discharge as part of the hospital's Clinical Measurement Initiative (CMI). ) that complement the electronic medical record (EHR) data. In addition, patients had the opportunity to opt for our genomics (biobank), wearable devices (actigraphy), real-time active and passive assessments of suicidal tendencies, and context-adapted multimodal informatics (CAMI, audio-visual recording of physician-physician interactions) . patients) initiatives such as these modalities were implemented in the units. This project received approval from the IRB.

Results:Over a two-year period, 753 hospitalized patients completed CMI on admission, 552 (73.3%) of whom also reported depression (QIDS-SR-16) and anxiety (GAD-7), symptom severity, and functional status (BASIS - 24), upon discharge from hospitalization. A large subgroup (n = 434, 57.6%) agreed to additional phenotyping, including biobanking (n = 301), actigraphy (n = 134), CAMI (n = 24), and suicidality-related assessments (n = 28). Most patients who met the inclusion criteria consented to BMI, but acceptability varied among the other phenotyping modalities, partly reflecting differences in participant burden and time to completion.

Participants showed robust improvement in depression (QIDS-SR-16 mean [SD] admission vs. discharge 15.6 [5.6] vs. 8.7 [5.0]; t(530) = 29.27, p < 0.001) and anxiety (mean GAD-7 [SD] admission vs. discharge 13.5 [5.9] vs 6.3 [5.1]; t(529) = 29.46, p < 0.001) Symptoms and functional status (mean BASE-24 [SD] admission vs. discharge 37.6 [14.1] vs 21.2 [11.9]; t(542) = 29.42, p < 0.001) during a brief acute hospitalization relative (mean [SD] = 12.6 days [14.9]). A similar improvement was seen in suicidal thoughts (BASIS-24 thoughts of end-of-life χ2(10, n = 542) = 300.5, p < 0.001; QIDS-SR-16 thoughts of death and suicide χ2(6, n = 545) = 266.0, p < 0.001) and BASE-24 thoughts of self-harm (χ2(10, n = 548) = 291.7, p < 0.001).

Positive BPD screening on the MSI-BPD was associated with worse severity of depressive symptoms and suicidal tendency at both admission (18.6 [4.4] vs. respectively) and discharge (9.8 [5.4] vs. 8.3 [4.8] p = 0.002 or 10 0.0% vs 7.8% of severe to very severe suicide p < 0.001), but not with length of stay (13.4 days [16.1] vs. 12.2 days [14.5] p = 0.4). A positive PTSD screening on the PCL-5 was associated with worse severity of depressive symptoms and suicidal tendencies on admission (19.1 [3.7] vs. 13.9 [5.7] p<0.001 and 50.5, respectively % vs. 33.7% of severe to very severe suicide p < 0.001). ), length of stay (14.7 days [16.1] vs. 11.4 days [13.9] p = 0.04) and severity of depressive symptoms (10.9 [5.3] vs. 7 .8 [4.6] p<0.001), but without suicide severity at discharge (10.1% vs. 8.8% of severe to very severe suicide p=0.2).

QIDS-SR-16 composite sleep disturbance on admission was associated with increased reports of "end-of-life thoughts" on admission (p = 0.001), and "too much sleep" on admission was associated with "end-of-life thoughts" " on the rise. QIDS-SR-16 Oversleeping was not associated with sleep duration derived from actigraphy measured up to the first 5 nights of use (F(3.58)=0.93, p=0.4). Sleep duration was not associated with QIDS-SR-16 “Thoughts about the end of life” on admission (F(4.57)=1.20, p=0.3), but was inversely associated with “Thoughts about the end of life” at discharge (F(3.58)=6.57, p=<0.001).

Conclusions:Adding a rotating set of deep phenotyping modalities to EHR data and routine PROM acquisition is quite feasible, albeit difficult, in a well-resourced hospital setting. Demographic, comorbid and actigraphic (sleep) factors modify the effect of hospitalization in patients hospitalized for depression/suicide and anxiety. We show robust improvements across a wide range of validated, standardized, and transdiagnostic outcome measures during a relatively short hospital stay. Early data suggest that quantitative sleep actigraphy may complement self-report measurements as a robust predictor of outcomes, particularly suicidal ideation, at discharge. Together, these data demonstrate the feasibility of in-depth phenotyping and quantitative assessments integrated into routine inpatient psychiatric care to provide real-world evidence for comparative efficacy and assessment of the heterogeneity of treatment outcomes.

Key words:Digital phenotyping, mood disorders, suicidal tendencies

Disclosure:Nothing to disclose.

Pushpa Kumari*, Vasin Dumrongprechachan*, Yevgenia Kozorovitskiy*

Northwestern University, Evanston, Illinois, USA

Background:Structural plasticity at the level of dendrites and dendritic spines, mediated by neuronal activity, critically shapes the development and behavioral wiring of mammalian brain circuits. Deficits in dendritic spine plasticity are central to neurological deficits and mental disorders. Recent studies characterize the role of pharmacological neuroactive agents, such as ketamine, psilocybin and entactogens, in alleviating these deficits. Despite extensive research focused on activity-dependent mechanisms of synaptic plasticity, the field lacks screening tools to perform accurate quantification of synaptic plasticity in a high-throughput format.

Methods:Here we are developing, characterizing, reducing and validating a high-throughput screening platform for dynamic measurements of structural plasticity, overcoming bottlenecks in drug discovery in neuroscience. The power of our platform lies in genetically encoded biosensor designs in which translation of a high-throughput compatible reporter, luciferase or nanoluciferase, fused to PSD95(Δ1.2) occurs under the control of synaptic activity-dependent promoters (Arc, director financial ). The reading of these sensors (change in luminescence signal) is a direct and quantitative measure of local translation and potentiation of dendritic spines. The best performance of 3 different sensor designs is developed in the studio. Cortical and hippocampal neuronal cultures from male and female mice are used, although the platform is compatible with neurons derived from human pluripotent stem cells. Each experiment generating imaging, Western blot data, or neuroplasticity results will include at least 3 biological replicates with multiple technical replicates. Repeated measures ANOVA is used for most statistical analyses.

Results:Our activity-dependent sensors reside in the dendritic spine of primary cortical neurons and provide a luciferase reading in response to known positive inducers of neuronal activity, such as forskolin (FSK), gabazine, and ketamine, in an activity-dependent manner. In accordance with NIH assay guidelines, z-score (z'>0.4, range 0.884-0.925) on two different concentrations of FSK and DMSO control ensures the quality and reproducibility of our HTS platform. Screening of approximately 1,280 FDA-approved small molecules, followed by unsupervised cross-sectional analysis, provided us with a preliminary list of key outcomes that may positively impact structural plasticity, including new and known modulators. We continue to validate new achievements using the de novo optically evoked spinogenesis platform to identify novel plasticity enhancers.

Conclusions:Taken together, our platform provides an unbiased, high-throughput screening approach that causally links neuronal activity to an accurate quantitative luciferase reading, enabling rapid screening of large numbers of novel neuroactive compounds. This approach should help to gain mechanistic insights into signaling pathways for the development of drug targets for fundamental neuroscience applications and therapies for various neurological and mental health disorders.

Key words:Neuroplasticity, dendritic spine, high performance

Disclosure:Nothing to disclose.

Chao Wang, Wei Wu*, Akshay Ravindran, Vinit Shah, Maimon Rose, Adam Savitz, Amit Etkin

Alto Neuroscience Inc., Los Altos, California, USA

Background:Antidepressants, such as selective serotonin reuptake inhibitors (SSRIs), are the first-line treatment for major depressive disorder (MDD); However, response rates remain low and current practice is still based on trial and error. Here, we sought to prospectively develop and validate a machine learning (ML) model to predict individual response to SSRI treatment, using 19-lead resting-state electroencephalography (rsEEG) data from two MDD clinical studies (total N = 346).

Methods:Data from 93 MDD patients in the SSRI arm of an open-label clinical trial were used for model development. Features extracted from pretreatment rEEG were used to construct an ML model to predict change in Hamilton Rating Scale for Depression (HAMD17) scores. The model was evaluated with 10-fold nested cross-validation and further tested prospectively on 42 patient samples with unobserved open-label SSRI. We also evaluated the model's ability to predict across studies by applying the model to the sertraline (N=99) and placebo (N=112) arms of a double-blind randomized clinical trial (RCT).

Results:We identified a regularized linear regression model that significantly predicted the change in HAMD17 score observed in the open-label study (r = 0.35, p < 0.001). Applying the model to the reserved samples produced similar results (r = 0.32, p = 0.019). The model was also generalizable across studies and was predictive of outcome in the sertraline arm of the RCT (r = 0.28, p = 0.003). It is important to note that when the model was applied to the placebo group of RCTs, the result could not be predicted (r = 0.03, p = 0.375), suggesting that the model was specific for SSRI (compared to placebo).

Conclusions:Our results showed that individual response to antidepressants can be robustly predicted in a specific way using EEG and machine learning. Successful prospective replication in the exclusion clause and generalizability across studies demonstrate the promise of accurate psychiatric approaches.

Key words:Depression, EEG biomarkers, machine learning, treatment prediction

Disclosure:Alto Neuroscience Inc.: Founder (Car), Alto Neuroscience Inc.: Employee (Car)

Leandra Figueroa-Hall*, Kaiping Burrows, Jennifer L. Stewart, Ahlam M. Alarm, Chibing Tan, Rayus Kuplicki, T. Kent Teague, Rajagopal Ramesh, Victoria B. Risbrough, Martin P. Paulus, Jonathan Savitz

Laureate Institute for Brain Research, Tulsa, Oklahoma, EUA

Background:About 1/3 of people with major depressive disorder (MDD) have inflammation, but the exact mechanisms are not known. Although experimental studies with lipopolysaccharide (LPS; endotoxin) have demonstrated behavioral, immunological, and physiological changes in healthy individuals, these studies fail to identify putative and divergent inflammatory and regulatory mechanisms in MDD or to distinguish between peripheral and central mechanisms. Therefore, a mechanistic approach is needed to identify which immunoregulatory mechanisms are defective in MDD. A plausible mechanistic pathway is the Toll-like receptor 4 (TLR4) pathway, which when activated by LPS produces inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF) that are elevated... people with MDD. Here we examine immune serum markers to identify peripheral changes and whether these markers correlate with TLR4-responsive miRNAs isolated from astrocyte-enriched extracellular vesicles (AEEVs).

Methods:This preliminary work utilized a randomized controlled trial (NCT#NCT03142919) of acute administration of LPS or saline in people with MDD and healthy controls (HC). This study was approved by the Western Institutional Review Board, obtained written informed consent from participants, and was conducted in accordance with the principles expressed in the Declaration of Helsinki. MDD (n=53) and HC (n=18) were randomly assigned to LPS (0.8 ng/kg) or placebo (saline) and serum samples for IL-6 and TNF from baseline (T0), 2 hours (T2), immunotyped. and 24 hours (T24) after LPS/saline infusion using mesoscale detection. For AEEV experiments, serum was used to isolate total EV and GLAST-biotin conjugated antibody was used for astrocyte enrichment. AEEV miRNA from previously published exploratory sequencing data [MDD (n = 8); HC (n = 5)] looking for correlations with IL-6 and TNF. Analyzes were performed in R Studio version 1.4.1717.

Results:Preliminary results showed statistically significant main effects of visit for IL-6 (F_(2.203)= 53,2, p < 0,001,a²_grama= 0,344) e TNF (F_(2.205)= 44,9, p < 0,001,a²_grama= 0.305), with paired comparisons indicating that T2 differed significantly from baseline and T24. There was no significant interaction between the effects of diagnosis and the visit for IL-6 and TNF, but there was a significant interaction between the effects of medication and the visit for IL-6 (F_(2.200)= 88,0, p < 0,001,a²_grama= 0,468) e TNF (F_(2.202)= 99,7, p < 0,001,a²_grama= 0.497). There was also a significant triple interaction between visit, medication, and TNF diagnosis (F_(2.196)= 3,28, p = 0,04,a²_grama= 0.032), but not IL-6. Previously published exploratory sequencing data showed statistically significant changes in several AEEV miRNAs, including hsa.let.7 f.5p and hsa.miR.374a.5p, which decreased at T2 and then reverted to baseline at T24. Here we show for the first time that hsa.let.7 f.5p has a positive trend relationship with IL-6 at T2 (r²= 0,196) e TNF (r²= 0,183)yhsa.miR.374a.5p com IL-6 (r²= 0,321) e TNF (r²= 0,253).

Statistics: 1. Serum immunological markers were compared with general linear models with diagnosis [MDD (n = 53) vs. HC (n = 18)] and drug [LPS (n = 12, HC); (n = 28, MDD) vs. saline (n = 6, HC); (n = 25, MDD)] as factors, visit*medication as the main interaction, and IL-6 as the main outcome. Shapiro-Wilk test for normality gave non-normal data for IL-6 and TNF, so data were log-transformed. A one-way ANOVA showed significant main effects of the visit on IL-6 (F(2.203) = 53.2, p < 0.001,a²_grama= 0,344) e TNF (F(_2.205)= 44,9, p < 0,001,a²_grama= 0.305). A two-way ANOVA showed significant drug-visit interaction effects for IL-6 (F(_2.200)= 88,0, p < 0,001,a²_grama= 0,468) e TNF (F(_2.202) = 99,7, p < 0,001,a²_grama= 0.497). A three-way ANOVA revealed a significant three-way interaction between visit, medication, and TNF diagnosis (F(_2.196) = 3,28, p = 0,04,a²_grama= 0,032).

2. Correlations were determined for the immunological markers and AEEV miRNAs, hsa.let.7 f.5p and hsa.miR.374a.5p; [MDD (n = 8); CH (n = 5)]. Here we show that hsa.let.7 f.5p has a positive trend relationship with IL-6 at T2

(r²= 0,196) e TNF (r²= 0,183) y hsa.miR.374a.5p con IL-6 (r²= 0,321) e TNF (r²= 0,253).

Conclusions:This is the first experimental study of LPS administration in depressed people. These preliminary results provide new insights into LPS-induced inflammatory responses after in vivo immunochallenge in MDD and their association with enriched miRNAs from extracellular vesicles in the brain. In vivo immunoprovocation elicits specific transient inflammatory responses in depressed individuals who are prone to AEEV miRNAs, which may help to elucidate the relationship between peripheral and central mechanisms in MDD.

Key words:Lipopolysaccharides, miRNA, astrocyte-derived exosomes (ADE), major depressive disorder (MDD)

Disclosure:Nothing to disclose.

Manish Jha*, Cherise Chin-Fatt, Abu Minhajuddin, Madhukar Trivedi

UT Southwestern Medical Center, Dallas, Texas, USA

Background:Recent reports have linked irritability to suicidal ideation (SI) in adults with major depression. Here we sought (Study 1) to assess whether the association between irritability and IS differs by age and (Study 2) to identify the neurocircuit-like mechanisms of irritability that mediate its association with IS.

Methods:Study 1: Subjects in the VitalSign Quality Improvement Project6 who had measurements of irritability [Concise Associated Symptom Tracking Irritability Domain (CAST-IRR)] and IF [Concise Health Risk Tracking Suicidal Thought Thought Factor (CHRT-SUI)] measurements became N = 2248 locked inside ). A linear regression analysis with an age per CAST-IRR interaction was used to assess whether the association between irritability and IS differed by age. In this analysis, CHRT-SUI was the dependent variable, age by CAST-IRR was the independent variable of interest, and gender, race, and ethnicity were covariates. To interpret the significant interaction, post hoc analyzes were performed in which separate linear regression analyzes were performed for pediatric (12 to 17 years old) and adult (18 to 64 years old) groups with CHRT-SUI as the dependent variable, CAST-IRR as the Dependent variable were performed variables. the independent variable of interest and gender, race and ethnicity as covariates.

Study 2: Participants in the Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC) study with available magnetic resonance imaging (MRI), CAST-IRR, and CHRT-SUI data (N = 274) were enrolled. Functional connectivity (FC) at rest was calculated between 121 cortical and subcortical regions (n ​​= 7260 FC pairs). Age, gender, race, ethnicity, and location were covariates in all regression analyses. Separate linear regression analyzes for each pair of 7260 FCs were used to assess their association with CAST-IRR and those with an unadjusted p-value <0.0005 were then used in the mediation analysis. Baron and Kenny's approach was used to assess whether FC pairs explain the effect of irritability on IS with age, sex, race, ethnicity, and location as covariates. This approach uses three separate linear regression models to assess how much of the predictive power of one variable (irritability) for an outcome (SI) is explained by a third variable (pair HR).

Results:Study 1: N = 1677 and N = 571 people were between 12-17 (children) and 18-64 (adults). The interaction between age and CAST-IRR was significant (p=0.0003), with the association between CAST-IRR and CHRT-SUI being greater in children (β=0.25, SE=0.03) than in adults ( β = 0.13, SE = 0.03). ) ) groupings.

Study 2: Fifteen CF pairs were associated with irritability at threshold p<0.0005, of which 9 CF pairs involved the striatum. Functional connectivity of the dorsal striatum with the lingual and superior temporal regions significantly (p < 0.05) mediated the association between irritability symptoms and SI.

Conclusions:The association between irritability and IS was stronger in adolescents than in adults. Dysfunctions within the corpus striatum may mediate this association and serve as a target for the development of new specific cardiovascular treatments. Future studies are needed to replicate and expand these findings, particularly in adolescents with depression.

Key words:Irritability, pediatric irritability, neurocircuitry, depressive disorders, resting-state fMRI

Disclosure:Acadia Pharmaceuticals: Contracted Research (owned), Janssen Research & Development: Contracted Research (owned), Neurocrine Biosciences: Contracted Research (owned), Navitor/Supernus: Contracted Research (owned), Eleusis: Advisory Board (owned), Eliem/ Worldwide Clinical Trials: Consultant (automatic), Guidepoint Global: Consultant (automatic), Janssen Global Services: Consultant (automatic), Janssen Scientific Affairs: Consultant (automatic), Medscape/WebMD: Fee (automatic), Clinical Care Options: Fee ( automatic ), NACCME: Fee (Auto), Global Medical Education: Fee (Auto)

Stephanie Bean, Rahul Dhanda*, Christina Graham, Deborah Hoffman, Mariam Rodriguez, Adrian Ionescu, Stella Karantzoulis, Sidney Kennedy, Sakina Rizvi

Neurocrine Biosciences, Inc., San Diego, California, USA

Background:Anhedonia is a core symptom of major depressive disorder (MDD) and is broadly defined as a loss of interest or pleasure. As a key diagnostic criterion for MDD, anhedonia contributes to patients' health-related quality of life and poor treatment outcomes. Therefore, accurate measurement of anhedonia is critical to reliably support research efforts and potential development of pharmacotherapy in MDD. The 17-item Dimensional Rating Scale for Anhedonia (DARS) was developed as a self-report tool to address the limitations of existing measures of anhedonia. In particular, the DARS was designed to be generalizable across cultures and patient experiences. To substantiate the available evidence on the measurement properties of the DARS, the aim of this qualitative study was to assess and establish the content validity of the DARS in adults with anhedonia in MDD through a targeted literature review (TLR), clinical interviews, and interviews with patients.

Methods:The TLR was performed to identify patient-relevant concepts (ie, signs/symptoms, impact of signs/symptoms on daily life and patient functioning) of anhedonia in MDD and to develop a preliminary conceptual model. The model was evaluated and reviewed through qualitative interviews with physicians (N = 6). Lessons learned from the TLR and clinical interviews were incorporated into the development of patient interview materials, including a concept assessment (CE)/cognitive report (CD) discussion guide. The CE exercise was designed to evoke concepts of anhedonia relevant to the patient in MDD, while the CD exercise was designed to assess the patient's understanding and application of the DARS through a reflect-aloud method. Individual telephone interviews were conducted with N = 20 patients with clinically confirmed anhedonia in MDD. The interviews were audio-recorded, transcribed, and then coded using qualitative analysis software to identify patient-relevant concepts reported, as well as the interpretation, clarity, and relevance of the DARS instructions, items, and response options. Reported concepts were analyzed for prominence (i.e., most relevant and important to patients), which were then used to finalize the conceptual model. An item mapping exercise was performed on the final model in order to assess the comprehensiveness of the DARS concepts.

Results:Twelve symptoms and 39 effects were reported by patients, of which 10 symptoms and 24 effects were considered prominent and used to finalize the conceptual model. The item mapping exercise revealed that the DARS provided adequate concept coverage in this patient population. The DC results indicated that the DARS prompts, items, and response options were generally well understood and comprehensible to patients. In addition, most item concepts have been shown to be relevant to patients' experiences; some discrepancies with specificity or relevance were identified for three items (ie two items in the eating/drinking area, one item in the social activities area).

Conclusions:The content validity of the DARS was assessed and confirmed by EC/CD hybrid interviews with patients with anhedonia in MDD. Additional performance and other measurement properties of the DARS will be assessed through planned psychometric analyses.

Key words:Clinical outcome ratings, patient-reported outcomes, content validity of a scale, the anhedonia dimensional rating scale

Disclosure:Neurocrine Biosciences: Employees (own)

Ruth Asch*, Ryan Cool, Sophie Holmes, Margaret Davis, Richard Carson, Patrick Worhunsky, Hilary Blumberg, Irina Esterlis

Yale School of Medicine, New Haven, Connecticut, USA

Background:Mania/hypomania is a defining diagnostic feature of bipolar disorder (BD), but depression is the most common clinical presentation, often leading to misdiagnosis of BD as major depressive disorder (MDD). The metabotropic glutamate receptor 5 (mGluR5) is involved in cognitive function and mood regulation, making it a potential treatment target for disorders associated with glutamate dysfunction, such as BD and MDD. Here we examine differences in mGluR5 between individuals with MDD, BD, and healthy controls (HC) and examine the relationships between mGluR5, brain function, and clinical symptoms.

Methods:Within each study, participants were well matched in terms of demographics (age, gender, race/ethnicity, smoking status). In Study 1, 62 subjects (37% male, 17 MDD, 27 BD, 18 HC) underwent positron emission tomography (PET) imaging with the [18 F]FPEB radiotracer to measure mGluR5 availability (estimated from the volume of distribution, VT) in three regions of interest: orbitofrontal (OFC), ventromedial (vmPFC) and dorsolateral prefrontal (dlPFC) cortices. (HC, MDD, BD) as independent variables, followed by Fisher LSD pairwise comparisons. To assess associations between mGluR5 dlPFC availability and clinical variables, we calculated Pearson's r. All tests were two-tailed and results were considered significant at p < 0.05. Statistical tests were performed in SPSS (v28).

In Study 2, we used functional magnetic resonance imaging (fMRI) to examine the BOLD responses of 48 subjects (48% male, 15 MDD, 14 BD, 19 HC) to displays of fearful facial affect (FEAR) and examined the correlations between FEAR and dlPFC responses Availability of mGluR5 measured by PET. fMRI processing and analysis were performed on the SPM12. The three stimulus conditions (Fear, Happiness, Neutral) were modeled separately in an event-related design that included regressors for motion correction parameters. Group differences in FEAR responses (FEAR > fixation) as well as relationships with dlPFC-mGluR5 availability and mood symptoms were examined using a standard linear model (i.e., one-way ANOVA with/without covariates). of interest). Whole brain group differences and correlations were examined at a voxel level of p<0.01 with a group level threshold of puncor<0.05 (kE>600). Mean FEAR BOLD responses were extracted for significant clusters identified in whole brain analyzes (MarsBaR) and ANOVAs with post hoc Bonferroni tests were used for pairwise comparisons. Participants in both studies completed clinical scales (MADRS, BDI, and POMS) to assess mood symptoms. The cognitive domains of working memory and psychomotor speed were assessed using the Cogstate battery of tests (Groton's maze learning test and screening test, respectively).

Results:In Study 1, there was a major group effect on mGluR5 availability (F =2.3, p =0.04), with mGluR5 in BD compared to MDD (p <0.01, -15.6%) and HC (p<0.04, -13.8%) was lower. 🇧🇷 In BD participants in depressed mood (n = 17), mGluR5 dlPFC availability was associated with psychomotor speed (r = -0.6, p = 0.03) and working memory (r = -0.5, p = 0). 0.03) associated ; and depressed mood (r = -0.7, p = 0.005) and working memory (r = -0.6, p = 0.05) in MDD patients. In Study 2, BD had higher FEAR responses at the right parietal-temporal junction compared to HC (padj = 0.03) and MDD (padj < 0.001) (p = 0.012, cE=830). There was a correlation between mGluR5 dlPFC and FEAR dlPFC/anterior cingulate (ACC) response in all subjects (p=0.012, kE=624). Median PFC/ACC FEAR response correlated negatively with mood symptoms in BD (p<0.001, kE=2728), but not with MDD.

Conclusions:These data demonstrate differences between BD and MDD in mGluR5 PFC availability and relationships between mGluR5 availability and brain function associated with emotion processing, which may affect clinically meaningful indices of mood symptoms and function. Furthermore, mGluR5-PET and fMRI may represent useful tools in the differential diagnosis of BD and mGluR5 as a potential therapeutic target.

Key words:Metabotropic glutamate receptor 5 (mGluR5), positron emission tomography (PET), functional magnetic resonance imaging (fMRI), bipolar disorder (BD), major depressive disorder (MDD)

Disclosure:Nothing to disclose.

Mark Frye*, Manuel Gardea Resende, Brandon Coombs, Marin Veldic, Susannah Tye, Francisco Romo Nava, Aysegul Ozerdem, Miguel Prieto, Alfredo Cuellar-Barboza, Nicolas Nunez, Balwinder Singh, Richard Pendegraft, Alessandro Miola, Susan McElroy, Joanna Biernacka, Eva Morava, Tamas Kozicz

Mayo Clinic, Rochester, Minnesota, USA

Background:Preclinical evidence suggests that antidepressants (ADs) may differentially affect mitochondrial energy. This study was conducted to examine the relationship between mitochondrial function and illness susceptibility in bipolar disorder (BD), specifically the risk of treatment-emergent mania (TEM).

Methods:Participants with BD who already had a clinical phenotype such as MET+ (n=176) or MET- (n=516) were further classified if MET associated with AD had increased based on preclinical studies (Myth+, n=600) or decreased (mito - , n = 289) mitochondrial electron transport chain (ETC) activity. A comparison of MET+ rates between Mito+ and Mito-AD was performed using generalized estimation equations to account for participants exposed to multiple ADs.

Results:Adjusted for gender and BD subtype, MET+ was more common with increased antidepressant medication (24.7%) compared with decreased mitochondrial energy (13.5%, OR = 2.12, p = 0.00002).

Conclusions:Our preliminary retrospective data suggest that it may be useful to rethink the classification of AD based not only on the mechanism of action of conventional monoaminergic drugs, but also on the basis of mitochondrial energy. Future prospective clinical trials on specific antidepressants and mitochondrial activity are recommended. Recognizing that the pharmacogenomic study of drug response can extend or overlap with the genomics of disease risk, future studies should explore possible interactions between mitochondrial mechanisms of disease risk and drug response.

Key words:Bipolar Disorder, Mitochondria, Electron Transport, Mania, Genetic Variation

Disclosure:Myriad: Grant (own), Assurex Health: Grant (own), Carnot Laboratories: Other financial or material support (own), Chymia: Other financial or material support (own)

Johanna Seitz-Holland*, Benoit H. Mulsant, Charles F. Reynolds III, Daniel M. Blumberger, Jordan F. Karp, Meryl A. Butters, Ana Paula Mendes-Silva, Erica L. Vieira, George Tseng, Eric J. Lenze , Breno S. Diniz

Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, Estados Unidos

Background:Depression in old age (LLD) is widespread and associated with excessive age-related medical morbidity, cognitive decline, and increased risk of mortality. Previous research has shown that at least a subset of people with LLD experience accelerated aging. Furthermore, previous studies have implicated the role of cellular senescence, a hallmark of biological aging, in accelerated aging in LLD. Senescence refers to a state of permanent cell cycle arrest and changes in the cellular secretome called the senescence-associated secretory phenotype (SASP). Previous studies have consistently shown increased expression of SASP proteins in subjects with LLD compared to healthy subjects. However, it is unclear how increased expression of SASP proteins is related to clinical presentations, including mental and physical health, in people with LLD. Therefore, the present study aimed to investigate which demographic, physical and mental health variables are associated with peripheral SASP proteins in LLD.

Methods:We examined the relationship between SASP and demographic, clinical, and cognitive variables in 426 people with LLD (mean age 68.9 years, 64% female). We obtained age, self-reported sex and self-reported race for all individuals. Features of major depressive disorder were assessed during the SCID-IV-TR interview, including duration of current depressive episode, age at onset of first depressive episode, recurrence, and comorbid anxiety disorders. Symptom severity was assessed using total scores on the Montgomery-Asberg Depression Rating Scale (MADRS), 17-item Hamilton Rating Scale for Depression (HAM-D), Brief Symptom Inventory (BSI), Questionnaire State of Concern (PSWQ), Sensitivity of Anxiety Index (ASI) Scores, Suicidal Thought Scale (SSI), Mental-Medical Outcomes Survey. We recorded self-reported years of training, Mini-Mental State Examination (MMSE), Repeatable Battery for Assessment of Neuropsychological State (RBANS), and Delis-Kaplan Executive Function System (DKEFS). In addition, we collected anthropometric data, pulse and blood pressure, fasting blood glucose, ICD 10 diagnosis of cardiometabolic disorders, Cumulative Disease Rating Scale - Geriatrics (CIRS-G) and Medical Outcomes - Physical Survey.

We calculated a SASP index based on 22 SASP proteins identified in preclinical studies and our previous publications.

Our statistical analyzes consisted of three steps. First, we performed three-factor analyzes to group clinical variables into domains related to 1) depression and anxiety traits, 2) cognitive functioning, and 3) physical health. Using regression analysis, we next examine the association between the SASP index and age and gender. Finally, we examined the relationship between the SASP index and the factors identified in the first step, performing correlation and regression analyses.

Results:Factor analysis identified two factors related to depression and anxiety (34.69% and 15.10% explained the variance, respectively), one related to cognitive functioning (55.64% explained the variance) and three related to physical health (27 .08%, 17.33%, 13.21% of the variance ). represented). Physical Health 1 included the CIRS-G and the Medical Outcomes Survey - Physical Scales, BMI, Glucose, Waist-to-Hip Ratio and Physical Comorbidities.

A regression analysis showed a significant influence of age (T = 5.24, p < 0.001, standardized beta = 0.24) and sex (T = -4.11, p < 0.001, standardized beta = -0.19) . Older and male participants had a higher SASP index.

A higher SASP index correlated with worse cognitive function (r=-0.18, p=0.001) and worse physical health 1 (r=0.41, p<0.001).

Regression analyzes with the SASP index as the dependent variable and age, gender and the six factors as independent variables showed a significant effect of age (p<<.001), gender (p<=0.0050) and physical health 1 (p<< ). 001). Physical health 1 was also the most significant independent variable when dividing our sample into men (p<0.001) and women (p<0.001).

Conclusions:Our results emphasized the role of physical health in accelerated aging in LLD. In addition, the SASP index was associated with age and gender, as well as cognitive function. In contrast, the SASP index was not associated with the severity or chronicity of depression and anxiety. This finding does not contradict our previous studies, which consistently showed a higher SASP index in individuals with major depressive disorders compared to non-depressed older adults. However, it does suggest that the SASP index is more likely to be associated with physical health and cognitive function in people with LLD. Therefore, our results are consistent with the view that depression is an unwelcome traveling companion with a concomitant medical burden and associated disability. In addition, they suggest that future treatment efforts should include interventions and lifestyle modifications that target overall health, such as: B. Exercise and weight loss programs and optimal management of chronic conditions such as diabetes, hypertension, and hypercholesterolemia. Furthermore, longitudinal studies are needed to understand whether inhibition of cellular senescence is a promising treatment target in LLD.

Key words:Depression, accelerated aging, senescence

Disclosure:Nothing to disclose.

Albert Arias*, Richard Feinn, Patrick Oliver

Virginia Commonwealth University, Richmond, Virginia, USA

Background:We recently reported a large retrospective case series (424 patients) of depressed patients (most with treatment-resistant depression) treated with intravenous ketamine in routine clinical practice (Oliver et al., in press). Good remission (38%) and response (72%) rates were achieved, but logistic regression did not produce significant and convincing predictors of response based on available phenotypic and demographic variables. Similar to other recent efforts to predict response to treatment in depression (Lin et al., 2021, Athreyu et al., 2019), we attempted to use machine learning on our extensive database to generate a model to predict response to depression. ketamine and identify important variables for prediction. 🇧🇷

Methods:Patients were N=400 adults with major depressive disorder (those of 424 with complete outcome data) and were recruited from the community as part of routine practice in private clinics. Ketamine infusions were administered at an initial dose of 0.5 mg/kg/40 minutes for six infusions over 21 days and continued as needed with titration of partial dissociation effect based on clinical course; more details are in the next post. The PHQ-9 was the primary outcome and was completed using an electronic form upon admission, before each infusion, and every fortnight thereafter. Response (>50% improvement from baseline) and remission (PHQ-9 score <5) were used as categorical endpoints. The Random Forest (RF) package in R Studio was used to generate outcome models based on 25 available demographic and phenotypic variables (e.g. gender, age, suicidal ideation, BMI, etc.).

Results:The RF model for remission was reasonably accurate in predicting outcome with area under the curve (AUC)  = 75.1% and an accuracy of 73.5%, with the response model being slightly less accurate; AUC = 71%, accuracy 68%. For remission, the most important variables in the model (most with a mean >5% reduction in the Gini index) were: baseline PHQ-9, total number of infusions, age, mean dose per kg, BMI, baseline anxiety , current use of benzodiazepines, history of alcohol problems and suicidal ideation, among others). The key variables in the response model were quite similar.

Conclusions:This preliminary exploratory analysis suggests that a number of variables that can be easily and quickly determined at the time of dosing may provide a good estimate of the likelihood of response and remission to ketamine treatment for potential patients with MDD. It could also be used to help estimate the optimal number of infusions to optimize a patient's likelihood of response. These models could also be improved by discovering additional important variables (e.g., neurobehavioral traits, transdiagnostic phenotypic traits, genetic markers) in future studies. While there is clearly room for improvement, these results suggest that further investigation of these precision medicine methods could advance the field.

Key words:IV- Ketamine, Ketamine, Treatment Resistant Depression, Machine Learning, Precision Medicine for Depression

Disclosure:Nothing to disclose.

Maurizio Fava, Vladimir Maletic, Chen Chen, Julie Adams, Ken Kramer, Majid Kerolous*

AbbVie, Madison, New Jersey, USA

Background:Anxiety symptoms are common in patients with major depressive disorder (MDD). The presence of these symptoms complicates the diagnosis and treatment of MDD and can adversely affect treatment outcomes. Cariprazine is a 5-HT1A preferential D3 dopaminergic agonist and D3/D2 receptor partial agonist approved for the treatment of adults with schizophrenia or manic, mixed, and depressive episodes associated with bipolar I disorder MDD and inadequate responses to antidepressant treatment (ADT) have have only been evaluated in late-stage clinical trials. In this post-hoc analysis, the effects of supplemental cariprazine on depression symptoms in patients with MDD and anxiety symptoms were evaluated using data from a positive, randomized, double-blind, placebo-controlled, fixed-dose Phase 3 study (NCT03738215). .

Methods:Patients with MDD and inadequate response to continuous ADT were randomized to placebo + ADT, cariprazine 1.5 mg/day + ADT, or cariprazine 3 mg/day + ADT for 6 weeks of double-blind treatment; The primary efficacy outcome was the change from baseline in the Montgomery-Åsberg Depression Rating Scale (MADRS) total score to week 6. Post-hoc analyzes assessed the change from baseline in the MADRS total score at subgroups of patients with and without baseline anxiety symptoms. The anxiety subgroup included patients with a baseline score ≥7 on the Hamilton Depression Scale anxiety/somatization factor (HAM-D) (sum of 6 items: psychological anxiety, somatic anxiety, gastrointestinal somatic symptoms, general somatic symptoms, hypochondriasis, and introspection). 🇧🇷 The analyzes used a mixed effects model for repeated measures; Statistical significance was determined using the 95% confidence interval (95% CI) plus the least squares mean difference (LSMD) compared to placebo.

Results:A total of 751 patients were included in the intention-to-treat (ITT) population and post-hoc analysis. In the all-inclusive ITT population, the difference in change in MADRS total score from baseline to week 6 compared with placebo + ADT after multiplicity adjustment for cariprazine 1.5 mg/day + ADT was statistically significant (-14.1 vs. -11.5; adjusted p=0.0050). but not for cariprazine 3 mg/d + ADT (-13.1; p = 0.0727). In post-hoc analysis, 83% of patients (627/751) met baseline anxiety criteria. In patients with pre-study anxiety, the least squares (LS) mean change from baseline to week 6 in MADRS total score was significantly greater for cariprazine 1.5 mg/d + ADT compared to placebo + ADT (- 14.1 vs. -11.7 , LSMD [95% CI] = -2.4 [-4.2, -0.7]); for cariprazine 3 mg/d + ADT, the mean LS change from baseline in MADRS total score was -13.1 (LSMD [95% CI] vs. placebo + ADT = -1.5 [-3.2; 0 , 3]). In the smaller subset of patients without anxiety at baseline (n = 124), the mean LS changes from baseline in the MADRS total score were numerically greater for cariprazine 1.5 mg/day + ADT (-12.8) and 3 mg/day + ADT (-12.8) and 3 mg/day Day + ADT (-10.1). compared to placebo + ADT (-9.8), but LSMD (95% CI) compared to placebo did not reach any of the cariprazine doses (1.5 mg/d = -3.0 [-7.3, 1.3], 3 mg/d = -0.4 [-4.5, 3.7]).

Conclusions:The high percentage of patients with anxiety symptoms in the study of positive fixed-dose cariprazine as adjunctive treatment in MDD corroborates previous findings that anxiety is a common feature of MDD. In a post hoc analysis, cariprazine 1.5 mg/day + ADT was associated with significantly greater improvement in depressive symptoms in the subgroup of patients with MDD and early anxiety compared with placebo + ADT. In patients without initial anxiety, the effect size versus placebo for cariprazine 1.5 mg/d + ADT was comparable to that seen in patients with initial anxiety, although the differences were not statistically significant, likely due to the small sample size in this group. . These results suggest that the addition of cariprazine was effective in reducing depressive symptoms in patients with MDD, regardless of whether or not they had anxiety symptoms at baseline.

Key words:Cariprazine, dopamine, major depression, anxiety

Disclosure:AbbVie: Employees (own)

Markku Lähteenvuo*, Tapio Paljärvi, Antti Tanskanen, Heidi Taipale, Jari Tiihonen

Niuvanniemi Hospital, Kuopio, Finland

Background:Bipolar disorder is a major psychiatric disorder with a prevalence of 2-3% across the bipolar spectrum. Treatment standards for bipolar disorder have changed in recent years, with the decline in the use of mood stabilizers and the increase in the use of antipsychotics. However, information on the comparative effectiveness of these different treatment options, particularly in real-world settings, is still scarce.

Methods:We identified everyone aged 16-65 years diagnosed with bipolar disorder (ICD-10: F30-F31) in Finland in 1987-2018 using Finnish national registries and included all individuals diagnosed with schizophrenia-interference spectrum (ICD-10) off . 🇧🇷 : F2X) or dementia (F00-F03, G30) before diagnosis of bipolar disorder (resulting cohort size: n = 60,045, 56.4% female, mean age 41.7 years (standard deviation (SD) 15 patients with newly diagnosed bipolar disorder) and no use of antipsychotics or mood stabilizers one year before initial diagnosis of bipolar disorder were also observed (incidence cohort, n = 26,395, 54.9 years) % females, mean age 38 .2 years (SD 13.0 years) Hospitalizations for Psychiatry (ICD-10 : FXX) and non-psychiatric reasons (ICD-10: any diagnosis other than F) as surrogate endpoints for relapse and safety or established PRE2DUP routine. eg, long-acting injectable antipsychotic (LAI) exposure vs. no use of an antipsychotic or lithium exposure compared with no exposure to mood stabilizers). Hazard ratios (HRs) with 95% confidence intervals (95% CI) for outcome measures based on drug exposures were calculated using Cox hazard models over subsequent years 1996-2018 using advanced within-individual modeling to remove selection bias. No exposures with use of less than 50 person-years have been reported. Separate analyzes were performed for the entire cohort and for the incident cohort. Risk ratios (aHR) were adjusted for the following covariates: other psychotropic drugs used, order of treatment, time since diagnosis of bipolar disorder.

Results:A total of 104,093 psychiatric hospitalizations were recorded during follow-up, distributed among 26,159 people. Drugs associated with a lower risk of psychiatric hospitalizations were olanzapine LAI (aHR 0.54, 95% CI 0.37-0.80), haloperidol LAI (aHR 0.62, 95% CI 0.47-0.81), zuclopenthixol LAI (aHR 0.66, 95% CI 0.52-0.85). 🇧🇷 ), lithium (aHR 0.74, 95% CI 0.71-0.76), clozapine (aHR 0.75, 95% CI 0.64 to 0.87), carbamazepine (aHR 0.81, 95% CI 0.75 to 0.87), levomepromazine (aHR 0.88, 95% CI 0.83). -0.93), lamotrigine (aHR 0.88, 95% CI 0.85-0.92), valproic acid (aHR 0.89, 95% CI 0.87-0.92), pregabalin (aHR 0. 92, 95% CI 0.86-0.98) and chlorprothixene (aHR 0.93, 95% CI 0.86-0.99). Medications associated with a statistically increased risk were quetiapine (aHR 1.03, 95% CI 1.00 to 1.06) and ziprasidone (aHR 1.26, 95% CI 1.07 to 1.49). Results were mostly similar for the incident cohort.

A total of 144,434 non-psychiatric (somatic) admissions were recorded during follow-up, distributed among 33,380 subjects. Of the drugs studied, only lithium (aHR 0.77, 95% CI 0.74-0.81) and carbamazepine (aHR 0.91, 95% CI 0.85-0.97) were associated with a significantly higher risk. reduced number of non-psychiatric hospitalizations, whereas risperidone (aHR 1.07; 95% CI 1.02-1.13), olanzapine (aHR 1.10, 95% CI 1.05-1.15), quetiapine (aHR 1 .10, 95% CI 1.07-1.13), haloperidol (aHR 1.12, 95% CI 1.03-1.22), melperone (aHR 1.19, 95% CI 1.03-1, 35), pregabalin (aHR 1.25, 95% CI 1.19-1.31), gabapentin (aHR 1.28, 95% CI 1.20-1.38), clozapine (aHR 1.29, 95% CI 1.07-1.55), ziprasidone (aHR 1.36, 95% CI 1.06-1.75) and haloperidol LAI (aHR 1.43, 95% CI 1.01-2.03) were significant with an increased risk of non-psychiatric hospitalizations. Results were similar for the incident cohort.

Conclusions:Lithium and certain long-acting injectable antipsychotics have been associated with better outcomes and should be preferred. Quetiapine and ziprasidone were associated with a significantly increased risk of psychiatric and non-psychiatric hospitalizations.

Key words:Bipolar Disorder, Antipsychotic Treatment Practice, Mood Stabilizers, Pharmacoepidemiology

Disclosure:Janssen: Honoraria (Auto), Janssen-Cilag: Honoraria (Auto), Lundbeck: Honoraria (Auto), Otsuka: Honoraria (Auto), Recordati: Honoraria (Auto)

Daniel Mueller*, Xiaoyu (Betsy) Men, Zachary Taylor, Victoria Marshe, James Kennedy, Eric Lenze, Benoit Mulsant, Charles Reynolds, Laura Ramsey

University of Toronto, Toronto, Canada

Background:Depression in old age (LLD) is characterized by major depressive disorder (MDD) in older adults aged between 50 and 65 years. LLD is often associated with medical comorbidities (eg, cardiovascular and cerebrovascular disease) and cognitive impairment. More than 50% of patients with LLD do not achieve remission or are at high risk of recurrence once in remission. Therefore, predictive models using genetic biomarkers will be useful to guide and optimize LLD treatment. Venlafaxine (VEN) is an antidepressant medication commonly prescribed to treat LLD. VEN is primarily metabolized to its active metabolite o-desmethylvenlafaxine (ODV) by the cytochrome P450 enzyme (CYP) 2D6. As VEN and ODV are pharmacologically active, the sum of VEN and ODV is often referred to as the active fraction (AM) and analyzed as a single pharmacological entity. In this study, we intend to use a pharmacokinetic (PK) modeling method that can estimate key PK parameters using sparse data at multiple time points to account for interindividual variability to assess 1) whether CYP2D6 genotypes for multiple VEN PK parameters and 2 ) the relationship between response to VEN treatment and drug exposure.

Methods:We studied people participating in "Incomplete Response in Late Depression: Coming into Remission" (IRL-GRey, NCT00892047). During Phase 1 of the IRL-GREy study, participants received open-label VEN for 12 weeks starting at 37.5 mg/day and starting at a dose of 300 mg/day if tolerated. Remission was defined as a MADRS score ≤ 10 at the last two consecutive visits. At the end of phase 1, the presence of side effects was also recorded using the UCU rating scale. We modified the existing Caudle et al. convert the CYP2D6 genotype to the metabolizer state by summing the activity values ​​of the haplotypes. Subjects were identified as CYP2D6 poor metabolisers (PM), intermediate metabolisers (IM), normal metabolisers (NM) and ultra-rapid metabolisers (UM). We have an earlier report by Lindauer et al. Adapted and modified the described pharmacokinetic (PK) model. in NO NEITHER. Our pharmacokinetic model was adjusted for body weight and CYP2D6 metabolizer status. We analyzed whether different CYP2D6 metabolizers had different VEN clearances and exposure of VEN, ODV, and AM by one-way ANOVA. In addition, we constructed regression models to assess the association between treatment response and drug exposure. The significance level was p-value < 0.05.

Results:The PK model (n = 304) showed good predictive power for VEN and ODV after adjusting for CYP2D6 metabolizer status and body weight. The four groups of metabolizers had significantly different model-estimated VEN clearance, VEN exposure, and ODV exposure, while there were no differences in metabolizer status at AM exposure.

Before dose adjustment, higher exposure to VEN, higher exposure to ODV, and higher exposure to AM were associated with lower treatment efficacy (n = 295). After dose adjustment, no association was found between treatment efficacy and dose-adjusted VEN exposure or dose-adjusted AM exposure. The overall presence of adverse events was associated with greater exposure to VEN, greater exposure to ODV, and greater exposure to AM (n = 287). For specific side effects, orthostatic dizziness was associated with higher VEN exposure and higher AM exposure. PMs in particular had the highest rate of orthostatic vertigo. Increased AM exposure was associated with nausea/vomiting.

Conclusions:We fit a transit PK model that fits our data well. Our results showed significant effects of CYP2D6 on estimated VEN PK parameters. By predicting pretreatment pharmacokinetic parameters, CYP2D6 extreme metabolizers, particularly CYP2D6 PMs, may benefit from genetic testing to prevent treatment-induced adverse events.

Key words:Depression in old age, pharmacogenetics, pharmacokinetics, venlafaxine

Disclosure:Nothing to disclose.

Roger McIntyre, Lakshmi Yatham, Eduard Vieta, Lauren Aronin and Binh Nguyen*

AbbVie, Madison, New Jersey, USA

Background:Bipolar I Disorder (BP-I) is a chronic mood disorder characterized by a mixture of manic, hypomanic, and depressive symptoms; Depressive symptoms are the main cause of morbidity and absenteeism. Cariprazine is a D3 preferential dopaminergic 5-HT1A and D3/D2 partial receptor agonist approved for the treatment of manic, mixed, and depressive episodes associated with BP-I. The efficacy of cariprazine in suppressing PA-I was demonstrated in 3 phase 2/3, randomized, double-blind, placebo-controlled, fixed-dose studies (NCT01396447, NCT02670538, NCT02670551). Data from these studies were pooled for post hoc analysis to assess clinically relevant improvement in symptoms using the 10 individual items of the Montgomery-Åsberg Depression Rating Scale (MADRS).

Methods:Patients were randomized to receive a fixed dose of cariprazine of 0.75 mg/day (1 study only), 1.5 mg/day, or 3 mg/day; the primary endpoint in each study was change in MADRS total score from baseline to week 6. For each individual MADRS item, a post-hoc analysis was performed to determine the percentage of patients with symptom change, mild or worse at baseline (MADRS item score) to be determined ≥2) to minimal or no symptoms (MADRS item score <2) at week 6; A more rigorous analysis also assessed the percentage of patients who progressed from moderate or worse symptoms (MADRS item score ≥ 4) at baseline to mild or better symptoms (MADRS item score ≤ 2) at week 6 from 0 to 6, with higher scores indicating greater severity of symptoms. Cariprazine 1.5 mg/d and 3 mg/d were pooled for post hoc analysis; Cariprazine 0.75 mg/day was not included because it is not within the recommended dose range for cariprazine. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated for each comparison of cariprazine versus placebo.

Results:The intent-to-treat pooled population included a total of 1383 patients (placebo = 460; cariprazine = 923 [1.5 mg = 461, 3 mg/d = 462]). For 9 of the 10 MADRS items, 67.5% to 100% of patients had mild to severe baseline symptoms (score ≥ 2) and 25.2% to 82.3% of patients had baseline symptoms ranging from moderate to severe (score ≥ 4); a smaller percentage of patients had suicidal ideation at baseline (score ≥2 = 14.2%; score ≥4 = 0%), probably due to the exclusion criteria of the original studies. A significantly greater percentage of patients treated with cariprazine compared with placebo progressed from mild or worse severity to minimal symptoms or no symptoms at week 6 on 8 of 10 MADRS items (OR [95% CI]): apparent sadness (1, 6 [1.2, 2.0]]; P = 0.0005]), reported sadness (1.6 [1.2, 2.0]; P = 0.0005), reduced sleep (1.5 [1 , 1; 1.9; P = 0.011), difficulty concentrating (1.5 [ 1.1, 2.0]; P = 0.005), fatigue (1.4 [1.1, 1.8]; P = 0.006), inability to feel (1.5 [1.2, 1.9]; P = 0.001) and pessimistic thoughts (1.5 [1.2, 2.0 ]; P = 0.001); no significant differences were found for the items internal tension and suicidal thoughts. In patients with moderate or worse baseline symptoms, a significantly greater percentage of cariprazine-treated patients changed to mild or better symptoms (OR [95% CI]) on 7 of 10 MADRS items compared with placebo: Apparent sadness (1.8 [1.4; 2.3] ; P < 0.0001), Reported sadness (1.5 [1.2, 2.0]; P = 0.008), Little sleep (1.3 [1.0, 1 .7]; P = 0.005), reduced appetite (1.8 [1.1, 2.9]; P = 0.002), difficulty concentrating (1.6 [1.2, 2.1]; P = 0.002 ), fatigue (1.6 [1.2, 2.1]; P = 0.001) and inability to feel (1.5 [1.1, 2.0]; P = 0.006); No significant differences were observed in the items “Tension” and “Pessimistic Thoughts” and no patient had a score ≥ 4 in the baseline “Suicidal Thoughts”.

Conclusions:A significantly greater proportion of patients treated with cariprazine compared with placebo were classified in a lower symptom severity category for most individual MADRS items. This suggests that cariprazine was associated with clinically significant improvement in a broad spectrum of depressive symptoms in patients with BP-I depression.

Key words:Bipolar-I-Depression, Bipolar-I-Störung, Cariprazin, Depression, MADRS

Disclosure:AbbVie: Employees (own)

Joshua Siegel*, Dean Wong, Demetrius Perry, Timothy Laumann, Abraham Snyder, Marcus Raichle, Eric Lenze, Nico Hosenbach, Ginger Nicol

University of Washington, St Louis, Missouri, United States

Background:Animal models suggest that psilocybin-induced limbic plasticity may be the key to its antidepressant effects. To understand how the neurotrophic and psychological effects of psychedelics are related, it is necessary to measure psilocybin-induced plasticity in humans.

Methods:In this crossover study, we used Precision Functional Mapping (PFM) and Diffusion Base Spectrum Imaging (DBSI) to assess changes in functional connectivity (FC) and inflammation, respectively, during and after psilocybin exposure in healthy adults ( 18-45 years) to eat. 🇧🇷 🇧🇷 Participants received 25 mg of psilocybin (PSIL) and 40 mg of methylphenidate (MTH) 1-2 weeks apart. Participants underwent multiple imaging sessions before, during (60 minutes after injections) and in the weeks following the medication sessions. Primary endpoints were image tolerability (defined as scan completion below a strict motion threshold), subjective experience (eg, Mystical Experiences Questionnaire), and limbic DBSI and HR.

Results:Six adults (3 women) completed the study. Resting-state precision fMRI was acquired approximately every other day for approximately 1 month, with an average of 34 scans (SD 5) per subject. Scans performed during PSIL sessions were performed by all participants, with high quality achieved in 5/6 participants. Measurable differences were seen between groups on the MEQ for all four factors (t-test; p < 0.05).

In the cortex, PSIL produced a decrease in BOLD signal strength in all regions, which was reflected in a reduced neurovascular response during the fMRI task. In the limbic system, PSIL produced an increase in HR between structures (hippocampus, amygdala, nacc, subgenual cingulum) that cannot be attributed to neurovascular or respiratory changes. Persistent changes in frontal hippocampal HR were observed 1 day after administration. No persistent changes (after vs. before) were observed in network modularity or signal strength. Participants showed a trend towards a decrease in the restrictive fraction of DBSI in the hippocampus (marker or inflammation) after exposure to PSIL (linear mixed-effects model, main effect of Timexdrug; p=0.08).

Conclusions:These results demonstrate that treatment-emergent changes in heart rate and inflammation, as measured by the PFM and DBSI methods, respectively, occur after exposure to PSIL and are observable in healthy young adults and are distinguishable from MTP. This study demonstrates the feasibility of precision imaging during acute PSIL exposure.

Key words:Psilocybin, resting state functional connectivity, precision psychiatry, hippocampus, inflammation

Disclosure:Nothing to disclose.

Stephen Daniels, Katerina Nikolitch, Jonathan S. James, Jennifer L. Phillips, Pierre Blier*

University of Ottawa Mental Health Research Institute, Ottawa, Canada

Background:Drugs that potently inhibit serotonin (5-HT) and/or norepinephrine (NE) reuptake are effective in the treatment of major depressive disorder (MDD). Serotonin/NE reuptake inhibitors (SNRIs) are the first-line treatment for MDD, but both venlafaxine and duloxetine require higher doses to inhibit the NE reuptake process than are needed to induce 5- HT to effectively inhibit. In a previous analysis, levomilnacipran, but not duloxetine, was shown to inhibit NE reuptake throughout its therapeutic range. Using positron emission tomography (PET), racemic milnacipran occupies only 60% of the 5-HT transporters at its minimum effective dose in MDD (100 mg/day), while duloxetine occupies 84% ​​when administered under normal conditions. No data are available for the occupancy of 5-HT transporters by levomilnacipran. An alternative approach to determining 5-HT reuptake activity was to determine 5-HT depletion in whole blood, since 90% of the 5-HT in the blood is found in platelets that do not synthesize 5-HT but have 5 -HT. HT transporter identical to that found in 5-HT neurons.

Methods:Healthy male participants (18-40 years) were initially randomized to placebo for 21 days, levomilnacipran (40 mg/day for 7 days, increasing to 80 mg/day for 7 days, then 120 mg/day for 7 days ). days) or duloxetine (60 mg/day for 7 days, 90 mg/day for 7 days, and 120 mg/day for 7 days). Participants were able to extend dosing periods to allow for adjustment of side effects. The concentration of 5-HT in whole blood was determined by high performance liquid chromatography from samples collected at stationary concentrations of the drug.

Results:There were 10 completers in the placebo group, 10 on levomilnacipran and 9 on duloxetine. Two participants discontinued due to side effects, one in each of the active treatment arms. Baseline 5-HT levels ranged from 400 to 500 pimol/mL and remained unchanged in placebo-treated subjects. Greater 5-HT depletion occurred within 7 days with duloxetine (75%) and levomilnacipran (85%), which were not significantly different from each other. Higher doses of both drugs further reduced 5-HT levels and were below the detection limit of our study (F2, 6: 6.13; P<0.001).

Conclusions:These results replicate our previous results using whole blood 5-HT depletion to determine the degree of inhibition of 5-HT reuptake induced by duloxetine at 60 mg/day. Such results are also consistent with PET imaging of the brain. Levomilnacipran was equally effective as duloxetine in blocking 5-HT reuptake, even at the lowest effective dose in MDD. Higher doses of levomilnacipran and duloxetine resulted in greater reductions in 5-HT levels, consistent with previous results using higher doses of the SNRI venlafaxine. These studies, along with previous results evaluating NE reuptake inhibition in this group of healthy participants, confirm that duloxetine is an SNRI that first inhibits 5-HT reuptake and requires titration to 120 mg/day to increase reuptake inhibition. from NE. In contrast, levomilnacipran acts as a dual reuptake inhibitor in its minimally potent regimen in MDD.

Key words:Serotonin transporter, peripheral blood marker, serotonin and norepinephrine reuptake inhibitor

Disclosure:Abbvie: Advisory Board, scholarship, fees (own)

A. Leslie Morrow*, Irina Balan, Riah Patterson, Giorgia Boero, Holly Krohn, Todd O'Buckley, Samantha Meltzer-Brody

University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA

Background:Brexananolone (FDA approval Feb 2019) has rapid, long-lasting, and remarkable efficacy (60% improvement in HAM-D score) in the treatment of postpartum depression (PPD). The treatment requires hospitalization and significant costs for the patient. Understanding therapeutic mechanisms provides information to address nuclear pathology in PPD. We tested the hypothesis that brexanolone inhibits pro-inflammatory immune signaling and macrophage responsiveness in patients with PPD to promote clinical recovery.

Methods:PPD patients treated at UNC hospitals provided blood samples before and after brexanolone infusion according to FDA-approved protocol. All patients were concomitantly treated with other psychotropic drugs, but were unresponsive prior to brexanolone therapy. Serum was collected for neurosteroid levels and isolated cell lysates were analyzed for baseline inflammatory markers and sensitivity to lipopolysaccharide (LPS) and imiquimod (IMQ) inflammatory triggers.

Results:Brexanolone infusion alters multiple levels of neuroactive steroids, inhibits inflammatory mediators, and desensitizes the inflammatory response to promote clinical improvement. Brexanolone infusion increased allopregnanolone (+2443 pg/mL, 95% CI 2009-2711, Bonferroni p=0.0001) and allotetrahydrodeoxycorticosterone (+63.4 pg/mL, 95% CI 48.3-78.4, p <α,5 of Bonferroni), while 3α,5-androsterone (-738 pg/mL, 95% CI -1243 to -232, p=0.03 of Bonferroni) and 3α,5α-androstanediol (-23.1 pg /ml, 95% CI -33.9 to -12.4, Bonferroni's p<0.001) strongly correlated with the HAM-D score. Brexanolone infusion inhibited tumor necrosis factor-α (TNF-α, 58%, p =0.03) and interleukin-6 (IL6, 61%, p <0.04), but not the inducible protein 10 by interferon-gamma, and these effects correlated with improvement in the HAM-D score (TNF-α: Pearson r = 0.61, p < 0.06; IL6: Pearson r = 0.68, Bonferroni's p < 0.03 ). Furthermore, brexanolone infusion prevented activation of TNF-α, IL1β and IL6 by both LPS and IMQ, suggesting a desensitized inflammatory response. Brexanolone infusion partially inhibited LPS-induced increases in IL-1β (-53.6%; Bonferroni p=0.03), IL-6 (-50.4%; Bonferroni p=0.03) and TNF- α (-31.3%; p = Bonferroni 0.02) . 🇧🇷 Brexanolone infusion also partially inhibited IMQ-induced increases in IL-1β (-48.9%; Bonferroni p  =0.02), IL-6 (-47.0%; Bonferroni p  =0.02) and TNF -α (-32.4%; Bonferroni-p= A Pearson correlation of 0.048 indicated that inhibition of LPS- or IMQ-induced elevation of IL-1β, IL-6, or TNF-α was positively associated with improvement in HAM score -D.

Conclusions:Data suggest that the therapeutic effects of brexanolone include inhibiting the production of inflammatory mediators by desensitizing immune cells and altering blood levels of endogenous neurosteroids. These data support the notion that inflammation plays a key role in postpartum depression and that inhibition of specific inflammatory pathways is the basis of its therapeutic efficacy.

Key words:Allopregnanolone, inflammation markers, depression

Disclosure:Sage Therapeutics: Grant (Auto), UNC Chapel Hill: Patente (Auto)

Adam Halberstadt*, Yasmin Schmid, Emma Bonniwell, Janelle Lanham, Abdi Ghaffari, Andrew Cao, Hooshmand Sheshbaradaran, John McCorvy

University of California, San Diego, La Jolla, California, USA

Background:Psychedelics such as lysergic acid diethylamide (LSD) and psilocybin induce hallucinogenic effects by activating the 5-HT2A receptor. Over the past two decades, substantial clinical evidence has emerged that LSD and psilocybin have therapeutic efficacy against a variety of psychiatric disorders, including depression, anxiety, headache, pain, and substance abuse. Similar to LSD, the closely related derivative 2-Bromo-LSD (2-Br-LSD, TD-0418A) is also being studied as a potential treatment for depression and headaches. However, the therapeutic efficacy of 2-Br-LSD is somewhat surprising, as 2-Br-LSD does not produce hallucinogenic effects in humans and has been reported to act as a 5-HT2A receptor antagonist.

Methods:A combination of in vitro and in vivo pharmacological studies were performed on 2-Br-LSD to assess its receptor interactions and possible mechanism of action. The interaction of 2-Br-LSD with 33 monoaminergic GPCR targets was assessed by G-protein dissociation and β-arrestin2 recruitment BRET assays. Head twitch response (HTR) studies were performed in male C57BL/6J mice to determine whether 2-Br-LSD has a similar behavioral profile to LSD (n=5-8 mice/group). HTR is a rapid head turn induced by psychedelics in mice, activating the 5-HT2A receptor. HTR was detected in mice using an automated procedure based on artificial intelligence.

Results:Compared to LSD, 2-Br-LSD shows significantly less off-target activity in GPCRs. The presence of a single bromine atom at position 2 of LSD results in partial agonist activity on several GPCRs, including the 5-HT2A subtype (Emax =59% relative to serotonin); In contrast, LSD has much greater agonist potency at 5-HT2A (Emax = 92%). Unlike LSD, 2-Br-LSD lacks activity at the 5-HT2B receptor, an interaction associated with valvular disease and pulmonary hypertension. While LSD (0.1 mg/kg IP) induced DTH in mice, administration of 2-Br-LSD in IP doses ranging from 0.1 to 10 mg/kg failed to induce the behavior. Furthermore, pretreatment with 2-Br-LSD (0.1–3 mg/kg IP) blocked HTR produced by the 5-HT2A/psychedelic agonist 2,5-dimethoxy-4-iodafetamine (DOI) (F( 4.26) = 17.96), p<0.0001), suggesting that 2-Br-LSD enters the brain and interacts with the 5-HT2A receptor after administration in vivo. We also found that 2-Br-LSD causes poor recruitment of β-arrestin by 5-HT2A in vitro and has reduced potential in the HTR paradigm to induce tolerance in vivo.

Conclusions:In general, 2-Br-LSD has an improved pharmacological profile compared to LSD. 2-Br-LSD appears to act as a non-hallucinogenic 5-HT2A agonist, similar to the isolysergic acid derivative lisuride. Our studies provide information about the non-hallucinogenic activity of 2-Br-LSD, which is probably a consequence of its weak partial agonist activity at the 5-HT2A receptor. Follow-up studies are needed to assess whether 2-Br-LSD can mimic the therapeutic effects of LSD but with less potential for hallucinogenic side effects.

Key words:Psychedelics, Psychedelic Medicine, LSD, 5-HT2A Receptor, Head Twitch Response

Disclosure:BetterLife Pharma Inc.: Commissioned Research (own)

Santosh Pothula*, Alexa-Nicole Sliby, Min Wu, Rong-Jian Liu, Ralph DiLeone, Ronald Duman

Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA

Background:A single subanesthetic dose of ketamine exerts rapid antidepressant effects through rapid glutamate efflux, activation of mTORC1 signaling, and enhanced synaptic transmission in the medial prefrontal cortex (mPFC); However, the initial cellular trigger for these synaptic and behavioral effects of ketamine remains unclear.

Methods:Here we use electrophysiological, biochemical, molecular biological, genetic, and behavioral approaches to determine fundamental sex differences in behavior following conditional deletion of GluN2B from Sst and Pvalb interneurons and the effect of ketamine on ketamine-induced behavioral deficits. CIS). , Activation of the mTOR signaling cascade and changes in synaptic transmission in knockout (cKO) mice mediated by GluN2Bfl/fl (WT) adult males and females and Sst-creGluN2Bfl/- and Pvalb-creGluN2Bfl/-. Post hoc Bonferroni ANOVA or one-way or two-way t-tests were used for data analysis and p<0.05 was found to be statistically significant.

Results:Acute treatment with ketamine significantly reduced the NMDA-induced burst firing of ex vivo Sst and Pvalb interneurons in the mPFC (p < 0.05). GluN2B knockdown of Sst or Pvalb interneurons in cKO resulted in changes in synaptic transmission in mPFCs. Consistent with the disinhibition hypothesis, ketamine significantly decreased inhibitory transmission but increased excitatory transmission from mPFC layers II/III and V pyramidal neurons (p < 0.05) and reversed the behavioral deficits caused by CUS alone. in WT but not in Sst-creGluN2Bfl/- induced Pvalb-creGluN2Bfl/-cKO mice. In contrast, ketamine treatment induced psychotomimetic effects (increased locomotor and sensorimotor activation deficits) in WT and Sst-creGluN2Bfl/- or Pvalb-creGluN2Bfl/- cKO mice in movement inhibition and pre-pulse tests. Preliminary data show that GluN2B knockdown of Sst interneurons blocks ketamine-induced activation of the mTOR signaling cascade. Ongoing studies are investigating the effect of ketamine on mTOR signaling in Pvalb-creGluN2Bfl/-cKO mice.

Conclusions:Our results indicate that GABAergic interneurons are an initial cellular trigger for the synaptic and behavioral antidepressant effects of ketamine. Consistent with the disinhibition hypothesis, ketamine's effects are mediated by GluN2B-NMDAR on GABAergic interneurons through disinhibition of pyramidal neurons, activation of mTOR signaling, and enhanced synaptic function in mPFCs.

Key words:(R,S)-ketamine, NMDAR, GABAergic interneurons, antidepressant, psychotomimetic effect

Disclosure:Nothing to disclose.

Krishna Vadodaria*, Brian D. Kangas, David S. Garvey, William Brubaker, Diego A. Pizzagalli, Vikram Sudarsan, Kimberly E. Vanover, Jordi Serrats

Engrail Therapeutics, San Diego, California, USA

Background:Anhedonia, defined as the loss of pleasure in previously rewarding activities, is a behavioral phenotype found in many neuropsychiatric disorders, including major depression. Alterations in dopaminergic corticostriatal (DA) circuits and dysfunction of mesolimbic DA pathways underlie deficits in reward processing. At low doses, amisulpride, a D2/3 and 5-HT7 receptor antagonist, has antidepressant effects and potentiates reward-related neuronal responses, while at high doses it has been used as an antipsychotic. We hypothesize that the prohedonic effects of amisulpride are mediated by its dopaminergic effects, specifically through blockade of presynaptic D2/3 inhibitory receptors at low receptor occupancy (RO), which in turn increases DA neurotransmission. Based on these findings, we designed a new selective D2/3 receptor antagonist, ENX-104, and predicted that it would improve response to a low dose reward (~40% D2/3 RO) without affecting motor functions. We characterized the in vitro pharmacological profile, pharmacokinetic (PK) profile, corresponding receptor occupations and behavioral effects of this new experimental compound, ENX-104.

Methods:The pharmacology of ENX-104 was characterized using in vitro binding (radioligand competition) and functional (agonistic or antagonistic mode) assays with separate cell lines overexpressing recombinant human receptors: D2L, D3, D4.4, 5-HT1A, 5- HT1B, 5-HT2A, 5-HT7.

For the pharmacokinetic characterization of ENX-104, rats received oral doses (n=3) (0.5 mg/kg [mpk] and 5 mpk) with plasma collection at eight post-dose times (5 min–24 h) with a group of Rats (n = 5) for plasma and brain collection 1, 4, 8, 24 h post-dose.

In the D2/3-RO study, rats (n=5) were orally dosed with ENX-104 at 2.5 mpk, and plasma and brains were collected at 1, 2, 4, 8, and 24 h post dose. In an ex vivo competitive marker binding assay, striated tissue was incubated with radioactively labeled [ 3 H]racloprid. Binding of labeled markers was inversely proportional to ENX-104 occupancy at D2/3 receptors. Vehicle comparisons were made using Dunnett's test. The PK and RO data were further used to build PK:pharmacodynamic (PD) models that allow prediction of D2/3 RO at different doses and time points after treatment with ENX-104.

To assess reward responsiveness, rats (n = 8) were trained on a touchscreen-based probabilistic reward task analogue (PRT) using parameters based on the human task. To translate this back into a preclinical model to predict antianedonic efficacy, we validated PRT with amisulpride. Vehicle, amisulpride (1, 5, 50 mpk) or ENX-104 (0.5, 1, 2.5 mpk) were administered orally 4-5 h before the PRT session in separate studies with an experimental design.

For motor function, rats (n=8) were orally administered ENX-104 (1, 2.5, 10 mpk) and catalepsy was assessed by an observer at 1.5, 3, and 4 h post dose. The rats' paws were gently placed in a rubber stopper and each paw remaining in place for at least 15 seconds was scored as 1 and the latency for the time each paw remained in the stopper was calculated. Vehicle comparisons were made using Wilcoxon exact rank sum tests.

All animal study protocols were approved by the IACUC and performed in accordance with NIH guidelines.

Results:ENX-104 is a potent dopamine antagonist with a Ki of 0.01 nM for D2L receptor subtypes, 0.2 nM for D3 receptor subtypes, and 1.6 nM for D4 receptor subtypes. Among serotonergic receptors, ENX-104 showed a binding affinity of 3.7 nM at the 5-HT2A receptor and acted as a partial antagonist (EC50 14 nM, Emax ~40%). In comparison, ENX-104 showed little or no functional activity at 5-HT1A and 5-HT7 receptors.

ENX-104 showed a short plasma half-life with significant cerebral accumulation and retention within 24 h. The plasma half-life of ENX-104 (0.5 mpk oral dose) is approximately 2 h with a tmax of approximately 30 min. Although plasma concentrations fall after 2 h, the maximum concentration in the brain is reached approximately 4 h after ingestion. These data correspond to the D2/3-RO time course data showing maximum receptor occupancy 4 hours post-dose. Based on these data, 4h was chosen as the key time point for the behavioral analyses.

In PRT, low but not high doses of amisulpride and ENX-104 targeting D2/3 RO significantly increased reward responsiveness. This was evidenced by a significant increase in response bias (log b) with no decrease in task distinctiveness (log d). Intra-subject general linear contrast model tests (square term) revealed statistically significant dose-response function for ENX-104 (p = 0.048) and a trend for amisulpride (p = 0.065). Given the a priori hypotheses, we performed paired t tests of log b values. Low doses of amisulpride differed significantly from vehicle (1 mpk, p=0.03; 5 mpk, p=0.04) and low doses of ENX-104 differed significantly from vehicle (0.5 mpk, p=0.006 and 1 mpk , p=0.04).

In particular, at lower doses (1 and 2.5 mpk), ENX-104 did not induce catalepsy. Catalepsy was observed only in the 10 mg/kg group (D2/3 RO > 80%).

Together with the PK:PD model, these data suggest that a D2/3 RO of ~40-60% is the target range for the anti-anedonic effects of ENX-104, with catalepsy occurring only at an RO greater than ~80%.

Conclusions:These data predict that ENX-104 could reduce anhedonia in humans at low doses without causing extrapyramidal side effects. Our data support further investigation of ENX-104, a new and potent D2/3 receptor antagonist, for clinical use in the treatment of anhedonia in psychiatric disorders.

Key words:Anhedonia, antidepressant, dopamine D2 antagonists, reward, depression

Disclosure:Engrail Therapy: Team (Own)

Charles Nichols*, Meghan Hibicke, Jason Middleton, Hannah Kramer, Jesper Kristensen

LSU Health Sciences Center, Nova Orleans, Louisiana, EUA

Background:Certain psychedelics, such as psilocybin, have demonstrated profound and long-lasting therapeutic benefits in a number of neuropsychiatric disorders, including depression and substance use disorders. Clinical studies have shown that a single treatment can provide therapeutic benefits that last for months to years. The molecular mechanisms underlying these effects are still unknown, but they are believed to involve changes in synaptic plasticity. We have previously shown that a single administration of psilocybin or lysergic acid diethylamide (LSD) to Wistar Kyoto (WKY) rats produced long-lasting antidepressant effects. In the forced swimming test (FST), immobility was dramatically reduced five weeks (35 days) after treatment with a large effect size. Furthermore, we also showed that a single psilocybin treatment eliminated deficits in object pattern recognition and decreased immobility in the FST when measured at five weeks in Sprague-Dawley rats exposed to the chronic stress of juvenile restraint. In these systems, we only tested the effects of psilocybin for five weeks. To assess the duration of action of a single administration of psychedelics and to examine the role of 5-HT2A receptors, we evaluated the effects of a single treatment with psilocybin and 25CN-NBOH (a selective 5-HT2A receptor agonist) on FST in at least 5 weeks and 12 weeks in WKY mice. In addition, we evaluated synaptic function at 12+ weeks in the vmPFC.

Methods:Adult male WKY rats were injected with psilocybin or 25CN-NBOH (i.p., HCl salt, 1.5 mg/kg) or sterile saline. After five weeks, all mice were tested in the FST. Rats were placed in a cylindrical plastic tank (114 cm x 30.5 cm) containing 30 cm of water at 28-30°C to swim for five minutes and film the sessions. Videos were scored for immobility, swimming, and climbing. 12 weeks after treatment, the mice were retested with the FST to examine the persistence of the effect. After completion of FST, mice were transcardially perfused with a neuroprotective artificial cerebrospinal fluid (aCSF), and brains were removed, sectioned, and whole cell electrophysiological recordings of layer V vmPFC pyramidal neurons (~3-5 neurons per animal) around the synaptics and to characterize intrinsic properties of these neurons.

Results:Both psilocybin and 25CN-NBOH resulted in a significant decrease in immobility and an equal increase in swimming behavior when measured at five weeks. These changes were stable and showed the same effect size when measured at 12 weeks. Cutting records showed that drug treatment depolarized the resting membrane potential and lowered action potential firing thresholds in regular spike neurons and had bidirectional effects on different classes of burst neurons: psilocybin increased the sEPSC in transient burst neurons and decreased the frequency of sEPSC in rhythmic oscillating burst neurons.

Conclusions:The effects of a single treatment with psilocybin or 25-CN-NBOH appear to be persistent, as no change in FST effect sizes was measured between 5 and 12 weeks. FST behavior is mediated by vmPFC projections to the dorsal raphe nucleus. Our results show that both drugs have long-lasting effects on synaptic function that facilitate the activity of neurons in the vmPFC. As the dose of 25CN-NBOH used is expected to be selective for 5-HT2A receptor activation, we conclude that 5-HT2A receptor activation is necessary and sufficient for the long-term effects of psychedelics.

Key words:Serotonin 5-HT2A Receptor, Psychedelics, Psilocybin, Depression, Model Systems

Disclosure:Eleusis Therapeutics: Advisory Board (Own), Eleusis Therapeutics: Stock/Stock (Own), Eleusis Therapeutics: Royalties (Own), Palo Santo Ventures: Advisory Board (Own)

Claus Normann*, Stefan Vestring, Katharina Domschke, Josef Bischofberger, Tsvetan Serchov

University of Freiburg, Freiburg, Germany

Background:Major depression is a widespread and devastating medical condition that causes enormous individual suffering and imposes a heavy socioeconomic burden. Despite their powerful effects, current medical treatment options are limited and traditional antidepressants take weeks or even months to relieve a patient's symptoms. Subanesthetic doses of ketamine effectively reduce depressive symptoms within hours, but are often accompanied by distressing side effects that limit its widespread clinical use. Identifying ketamine's primary target and subsequent mechanisms relevant to its antidepressant efficacy could lead to more targeted interventions with fewer side effects and better patient outcomes.

Methods:Young adult mice of both sexes were used for all experiments. Hippocampal brain slices were obtained after decapitation and patch-clamp recordings were performed according to previously published protocols for measuring long-term synaptic plasticity (LTP), NMDAR currents and other cellular parameters. Sections from mice expressing tdTomate in SOM-IN (SOM-Cre (SST tm2.1(cre)Zjh/J) were used to evaluate SOM-IN. Protein and RNA levels were determined by Western blotting and RT-PCR evaluated. For behavior, the chronic hopelessness model of depression, the nose sucrose preference test in the IntelliCage and an open field test were used.SIRNA GRIN2D was obtained by intrathecal injection along with in vivo jet-PEI solution applied.

Results:We began by investigating the behavioral antidepressant properties of ketamine in an animal model of chronic distress depression (CDM). In the CDM, the animals underwent ten-minute forced swimming sessions to induce a depression-like state for five consecutive days, followed by a two-day rest period, and then several reading assessments were performed. After a single intraperitoneal injection of ketamine (10 mg/kg body weight), immobility time was significantly reduced to baseline values ​​and sucrose preference was normalized. In ex vivo hippocampal brain slices, LTP induction was completely abrogated after swimming stress and fully restored by ketamine treatment. In brain slices from virgin animals, ketamine facilitated LTP induction in a protocol designed to avoid ceiling effects. However, the underlying mechanism of this effect is not apparent, as LTP in the hippocampus is dependent on N-methyl-D-aspartate (NMDA) and ketamine is a non-competitive NMDA receptor antagonist. NMDAR is a heterotetramer composed of two GluN1 and two GluN2 subunits with generalized synaptic and extra-synaptic distribution in different brain neurons. A potential mediator of positive LTP modulation may be somatostatin-expressing interneurons (SOM-INs), which represent an important subpopulation of GABAergic interneurons and induce feedback inhibition to the distal dendrites of PCs in the hippocampus and frontal cortex. As part of a feedback loop, these interneurons effectively control postsynaptic NMDA receptor activation and synaptic plasticity. In brain slices, NMDAR currents were more inhibited in SOM-IN than in pyramidal cells. GluN2D subunits are preferentially expressed in SOM-IN and ketamine has greater affinity for NMDARs containing this subunit. Selective inhibition of GluN2D-containing NMDA receptors restored stress-induced blockade of long-term synaptic potentiation, which is reinforced at later stages by structural synaptic modifications. The cellular and behavioral effects of ketamine can be fully mimicked in vitro and in vivo by the selective GluN2D antagonist NAB-14 and the small interfering RNA (siRNA)-mediated post-transcriptional silencing of its GRIN2D-encoding gene in vivo.

Conclusions:These results identify the GluN2D NMDA receptor subunit on interneurons as new and highly specific targets for the pharmacological treatment of major depression, including RNA-based therapies.

Key words:Depression, synaptic plasticity, NMDA receptor, in vivo treatment with siRNA, ketamine

Disclosure:Janssen Pharmaceuticals: Fee (own expense), GluN2D Antagonists to Treat Depression: Patent (own expense)

Yukio Ago*, Rei Yokoyama, Atsushi Kasai, Masato Tanuma, Misuzu Hayashida, Yuto Shimazaki, Momoko Higuchi, Hisato Igarashi, Kaoru Seiriki, Shun Yamaguchi, Takanobu Nakazawa, Kenji Hashimoto, Hitoshi Hashimoto

Hiroshima University, Hiroshima, Japan

Background:Esketamine and arcetamine are the S(+) and R(-) enantiomers, respectively, of ketamine, and esketamine nasal spray was recently developed and approved for treatment-resistant depression. Evidence is accumulating from studies in rodents to suggest that archetamine may have a more potent antidepressant effect and cause less cognitive impairment than esketamine, but the antidepressant mechanism of ketamine enantiomers is not fully understood. In the present study, we sought to explore and identify brain regions that contribute to the difference in antidepressant effects between ketamine enantiomers by mapping immediate early gene expression throughout the brain.

Methods:Experimental animal care and procedures were performed in accordance with the guidelines in the Guide to the Care and Use of Laboratory Animals, and all animal experiments were approved by the Animal Care and Use Committees of Osaka University. We used the social isolation of mice after weaning as a model of depression. Male C57BL/6J mice were weaned on postnatal day 21 and assigned to group housing or isolation. On day 63, mice were subjected to a 6-minute session of a forced swim test (FST). To visualize neuronal activation at full-brain scale with subcellular resolution, we used Arc dVenus mice expressing a destabilized fluorescent reporter protein dVenus under the Arc Immediate Early gene promoter and analyzed dVenus expression in the whole brain of mice in an unbiased manner using a automated FAST (block face serial microscopy tomography) imaging that we have recently developed (Seiriki et al., Neuron 2017; Nat Protoc 2019).

Results:The stress of social isolation prolonged the immobility time of mice in the FST, and archetamine had a greater antidepressant effect than esketamine in mice reared alone. Both arcetamine and esketamine increased neural activity in cortical and subcortical regions in Arc-dVenus mice reared in isolation, and then whole-brain activation mapping machine learning classifiers identified several candidate brain areas, including the cortex, the agranular rostral island, which could contribute to the antidepressant effect of arketamine and discrimination between the effects of arketamine and esketamine. Furthermore, acute chemogenetic-mediated inhibition of excitatory neuronal activity in the rostral agranular insular cortex blocked the antidepressant effects of archetamine, but not esketamine, in mice reared alone. In contrast, chemogenetic activation of rostral agranular insular cortex neurons induced antidepressant effects in mice reared alone.

Conclusions:These results suggest that esketamine and arketamine have different neural mechanisms underlying their antidepressant effects. This study also implies that activation of the rostral agranular insular cortex is essential to exert the antidepressant effects of arketamine.

Key words:Arketamine, esketamine, insular cortex, antidepressant mechanisms, neural activity

Disclosure:Nothing to disclose.

Kyle Brown*, Panos Zanos, Ruin Moaddel, Xi-Ping Huang, Chris Powels, Mike Michaelides, Edna Pereira, Todd Gould

University of Maryland School of Medicine, Baltimore, Maryland, USA

Background:Benzethonium chloride (BZT) is an antimicrobial adjuvant used in a number of products, including (R,S)-ketamine (ketamine) drug formulations. A 10 µM ketamine formulation, a concentration commonly used in preclinical studies, contains up to 12 nM of BZT. Recent evidence suggests that BZT is functionally active. Therefore, BZT may contribute to some of the clinical or preclinical effects seen with ketamine.

Methods:We evaluated the affinity and functional effects of BZT on neurotransmitter receptors and transporters. Radioligand binding assays determined the affinity of BZT for multiple targets, while functional effects were assessed by neurotransmitter uptake, β-arrestin translocation, cAMP production and/or Ca2+ mobilization. Plasma and brain distribution of BZT was determined up to eight hours after systemic administration (ie, intraperitoneal administration) in male mice. The effect of BZT on in vitro synaptic transmission was evaluated in the hippocampus of male mice by electrically stimulating Shaffer's collateral afferents and recording excitatory postsynaptic field potentials (fEPSPs) in the CA1 subfield.

Results:BZT binds strongly to several receptors with high to moderate affinity (eg, σ2 Ki = 7 nM; n = 3–5 independent experiments per receptor), inhibited transporter activity (eg, dopamine transporter Ki = 545 nM ; n = 3 independent experiments per carrier) and did not show agonist activity at any of the metabotropic receptors tested (n = ≥ 3 independent experiments per receptor). BZT was detected in the periphery but not in the brain of mice after systemic administration (n=4 at 10, 30, 60, 120, 240 and 480 min after BZT injection). Application of BZT-enhanced hippocampal Schaffer-CA1-fEPSP bath to mouse hippocampus slices (F(6,142)=6.60, p<0.0001; EC50=2.03 nM). In particular, the bath application of 10 nM BZT (p<0.0001; n=14), 50 nM BZT (p=0.028; n=17) and 300 nM BZT (p=0.021; n=18), ) n=48 ), 0.3 nM BZT (p = 1.00; n = 19), 2 nM BZT (p = 0.72; n = 19) or 10000 nM BZT (p = 0.067; n = 1SP), = Significantly increased pending value. Separate experiments showed that the enhancing effect of 10 nM BZT persisted after BZT elimination (t(5)=0.987, p=0.37).

Conclusions:BZT interacts with numerous membrane receptors and can induce synaptic potentiation measured in hippocampal slices. However, it does not easily cross the blood-brain barrier. Studies measuring peripheral outcomes after treatment with ketamine containing BGZ or exposure of systems directly to ketamine formulations containing BGZ (eg, intracortical administration) should consider the effects of BGZ. Our results suggest that previous data attributing physiological effects to ketamine may be affected by BZT and that further investigation of the functional effects of BZT is warranted.

Key words:(R,S)-ketamine, synaptic plasticity, hippocampus, shear electrophysiology, neurotransmission

Disclosure:Nothing to disclose.

Veronica Begni, Moira Marizzoni, Diana Morena Silipo, Kerstin Camile Creutzberg, Mariusz Papp, Annamaria Cattaneo, Marco Andrea Riva*

University of Milan, Milan, Italy

Background:Exposure of adult rats to chronic stress represents a valuable experimental paradigm for studying and characterizing the mechanisms that may contribute to the development of a pathological phenotype. A consistent finding after exposure to stress is the development of an anhedonic phenotype, which can be normalized by pharmacological intervention with various psychotropic drugs. Anhedonia is a key domain in mood disorders and arises from a range of disturbances in different brain regions. In this sense, the prefrontal cortex can play a crucial role, considering that it receives a range of functional inputs and plays important modulatory roles in other structures, including the amygdala and the nucleus accumbens.

Here, we performed transcriptome analysis in the prefrontal cortex of rats exposed to the mild chronic stress (CMS) paradigm and investigated the possible effects of chronic treatment with the antipsychotic lurasidone on such transcriptional changes to identify genes that contribute to stress susceptibility, as those that may play a role in therapeutic intervention with lurasidone.

Methods:Adult male rats were initially exposed to CMS for 2 weeks and sucrose intake was measured as an indicator of anhedonia. Animals that showed reduced intake (susceptible) were randomized to receive the vehicle or the antipsychotic lurasidone (3.0 mg/kg, orally) for an additional 5 weeks, while exposure to CMS was continued. Blood and brain tissue were collected for molecular analysis 24 hours after the last manipulation.

Whole-genome RNA sequencing analysis was performed using the Illumina NextSeq500 platform on the prefrontal cortex (PFC) of vehicle-treated control mice (CT/Veh), vehicle-treated CMS mice (CMS/Veh), and vehicle-treated mice. CMS with lurasidone (CMS /Lur). Differentially expressed genes (DEGs) identified by Bioconductor's Deseq2 package with FDR-corrected p-values ​​(q < 0.05) were used to perform path analyzes and predictions of functional networks via Ingenuity Pathway Analysis (IPA).

Results:Consistent with our previous studies, CMS exposure caused a significant reduction in sucrose intake, which progressively normalized with lurasidone treatment (p<0.001).

Transcriptomic analysis in the prefrontal cortex allowed us to identify a large number of genes (>500) differentially expressed in CMS/Veh compared to CT/Veh, but also differentially expressed in CMS/Lur compared to its vehicle. treated counterparty (CMS/Veh).

Using Venn diagram analysis, we found that 107 common genes were altered in the CMS/Veh and CMS/Lur groups. By performing path analysis, we found that most of these paths have opposite modulation. Indeed, among the most significant changes, we found that netrin, CREB, and oxytocin signaling pathways were down-regulated in CMS/Veh and up-regulated in CMS/Lur. Likewise, based on disease and function analysis, we observed increased cell and neuronal death in CMS/Veh with opposite changes in lurasidone-treated rats.

Conclusions:In summary, we provide new insights into how chronic treatment with lurasidone can counteract the impairments caused by prolonged exposure to stress, a major vulnerability factor for mental disorders. In particular, the prefrontal cortex appears to be particularly sensitive to stress exposure, down-regulating several pathways associated with neural guidance and synaptic plasticity. Our results suggest that pharmacological intervention with lurasidone can counteract such changes and ultimately promote resilience.

Key words:Chronic stress, transcriptomics, lurasidone, plasticity

Disclosure:Angelini: Speakers Workshop (auto), Lundbeck: Speakers Workshop (auto), Otzuka: Speakers Workshop (auto), Sumitomo Pharma: Honorary (auto), Sumitomo Pharma: Subvención (auto), Sunonion: Subvención (auto)

Hajime Miyanishi*, Shinichi Muramatsu, Atsumi Nitta

Graduate School of Medicine and Pharmaceutical Sciences, Toyama University, Toyama-shi, Japan

Background:Depression is one of the most common mental illnesses with an increasing number of people worldwide. Stress is closely related to depressive pathology. While some individuals are prone to stress, others are resilient. Uncovering the regulatory mechanisms underlying stress sensitivity may provide new insights into understanding the pathogenesis of depression. Serotonin [5-hydroxytryptamine (5-HT)] is involved in the pathogenesis of depression and 5-HT has been the target of medical treatments for depression. Hereditary reduction in brain 5-HT-induced susceptibility to social stress in mice. Shati/Nat8l was identified in the brains of model mice of methamphetamine-induced psychosis. Shati/Nat8l has N-acetyltransferase activity and mainly synthesizes N-acetyl aspartate (NAA) from L-aspartate and acetyl coenzyme. It has been reported that brain expression of NAA is altered in patients with depression. Previously, we found that Shati/Nat8l mRNA levels were increased in the dorsal striatum in mice exposed to the repeated stress of forced swimming. In the present study, we demonstrate the role of the Shati/Nat8l striatum in the pathology of depression and stress sensitivity.

Methods:Male C57BL/6J mice were subjected to repeated social stress (RSDS) with male ICR mice, and the stress-prone or stress-resistant group was classified using a social interaction test. We generated Shati/Nat8l mice with dorsal striatal overexpression (dSTR-Shati OE) using adeno-associated virus vectors. Depression-like behaviors were assessed using these mice after RSDS or subthreshold social stress (microsocial defeat stress; MSDS). The 5-HT content in the dorsal striatum was measured using in vivo microdialysis. The effects of 5-HT on the dorsal striatum on stress sensitivity were examined by microinfusion of the selective serotonin reuptake inhibitor fluvoxamine (FLX) into the dorsal striatum. We also examined the contribution of the 5-HTergic neuron projecting from the raphe nucleus to the dorsal striatum to stress sensitivity using the DREADD system.

Results:We found that Shati/Nat8l mRNA levels were increased in the dorsal striatum of stress-sensitive but non-stress-resistant mice exposed to RSDS. We also found that only stress-prone mice showed downregulation of 5-HT levels in the dorsal striatum. The proportion of the stress resistant group after RSDS decreased to 50% in dSTR-Shati OE mice compared to control mice, and these mice even showed susceptibility to MSDS. Reduced 5-HT content in the dorsal striatum was observed in dSTR-Shati-OE mice. Stress susceptibility in dSTR-Shati-OE mice was alleviated by microinfusion of FLX into the dorsal stratum or by activation of the 5-HTergic neuron projected from the raphe nucleus to the dorsal striatum by the DREADD system.

Conclusions:In the present study, we show that vulnerability to Shati/Nat8l-induced striatal stress is mediated by reduced striatal 5-HT content by the 5-HTergic system in the raphe nucleus. Our study suggests that the stress-sensitive striatal-dorsal raphe circuit is involved in the pathogenesis of depression and that the Shati/Nat8l striatal circuit may be a new therapeutic target for depression.

Key words:Depression, social defeat stress, dorsal striatum, dorsal raphe, serotonin

Disclosure:Nothing to disclose.

Argel Aguilar Valles*, Vern Lewis, Andre Telfer, Emily Arsenault, Fatimeh-Frouh Taghavi-Abkuh, Fatema El Sayegh, Alfonso Abizaid

Carleton University, Ottawa, Canada

Background:Major depression (MDD) is the leading cause of disability worldwide. Current pharmacotherapeutic treatments, such as SSRIs and SNRIs, have long effective latencies, require chronic administration and have an estimated rate of treatment resistance of 30-40%, necessitating the search for more effective alternative treatments. Interest in psychedelic hallucinogens (eg, lysergic acid diethylamide [LSD], psilocybin) has resurfaced for their potential to treat neuropsychiatric disorders such as anxiety and depressive disorders. Unlike first-line treatments for MDD, hallucinogens target serotonin receptors directly and exhibit rapid and sustained antidepressant effects after only one or two treatments, possibly due to activation of synaptic mechanisms and structural plasticity. However, psychedelics induce hallucinations that can last for hours, making effective and inexpensive treatment difficult. Therefore, the discovery of non-hallucinogenic derivatives with antidepressant properties is of paramount importance. 2-Bromo-LSD (2-Br-LSD, BETR-001) is an LSD derivative with 5-HT2A partial agonist activity that is devoid of hallucinogenic effects and has been used safely to treat cluster headaches. Therefore, 2-Br-LSD may represent a new therapeutic potential for the treatment of neuropsychiatric disorders whose pathologies involve dysfunction in cortical serotonergic pathways.

Methods:We examined the effects of 2-Br-LSD on dendriteogenesis in cell cultures of primary cortical neurons from rats. Cortices from 18-day-old mouse embryos were enzymatically and mechanically disaggregated; Cells were then plated at 50,000 cells/well and treated with various concentrations of 2-Br-LSD (1, 10, and 100 nM, 1, and 10 µM), 10 µM ketamine, or vehicle for 3 hours on in vitro days (DIV3). . In DIV6, cells were processed for immunofluorescence for MAP2 detection or for cell survival using the Neurite Growth Stain Kit (Thermo Fisher). Sholl analysis was used to quantify changes in tree complexity in mapped cells. To assess spinogenesis, neurons up to DIV18 were cultured, treated as above, and stained for MAP2 and F-actin. To assess the contribution of the 5-HT2A serotonin receptor to 2-BR-LSD dendritic genesis, DIV3 neurons were pretreated with the selective 5-HT2A antagonist volinanserin (VOL) at 100 nM, 500 nM or 1 µM per 1 hour. followed by vehicle or 2-Br-LSD (1 µM). Neurons from 6 different wells per treatment and from at least 2 independent experiments were used for the analyses.

To determine the effect of 2-Br-LSD on stress coping behavior, adult male and female mice (n = 12 groups/sex) were treated with vehicle or 2-Br-LSD at 0.3, 1, or 3 mg/day. kg ( IP ). 24 hours after treatment, mice were tested in the field (OF, 10 min) and 1 hour later in the forced swim test (FST, 6 min). Immediately afterwards, brains were harvested and processed for Golgi staining (FD Rapid GolgiStain Kit, FD NeuroTechnologies). A separate cohort of mice (n=11/group) was treated 15 minutes before 2-Br-LSD (IP, 1 mg/kg) with VOL (IP, 0.125 mg/kg) or vehicle and then on OF and FST day tested. Finally, a group of female mice was exposed to variable chronic stress (CVS; 2 stressors per day in variable order) for 5 weeks (n=12/group). After the last day of stress, mice were treated once with vehicle or 2-Br-LSD (IP) at a dose of 3 mg/kg or three times every 48 hours at a dose of 1 mg/kg. Mice were tested in the field and in the spray test at two time points after treatment (3-4 h and 4 weeks).

Results:2-Br-LSD induced a dose-dependent increase in the complexity of dendritic waves, reflected in an increase in the number of process crossings in the Sholl analysis and an increase in the dendritic wavelength. The maximum effect was achieved with the 1 µM dose, comparable to a 10 µM ketamine treatment. 2-Br-LSD also increased spinal density in DIV18 neurons, but only at the 10 μM dose. None of the treatments decreased cell viability in cultured neurons.

In vivo, 2-Br-LSD reduced FST immobility at a dose of 1 mg/kg in male and female mice without affecting overall FO locomotion. Furthermore, this treatment increased spinal density in the prefrontal cortex. Treatment with 2-Br-LSD also reversed the effects of CVS in female mice, prompting research and maintenance of the OF center in the splash test.

The promotion of in vitro dendritogenesis and active stress coping behavior by 2-Br-LSD was dependent on 5-HT2A receptors, as VOL blocked both effects.

Conclusions:Our results demonstrate that 2-Br-LSD induces structural plasticity in cortical neurons in vitro and in vivo, promotes active stress-coping behavior, and reverses the behavioral effects of CVS. These results indicate that 2-Br-LSD has therapeutic potential and represents a promising alternative to psychedelics in the treatment of MDD.

Key words:LSD, dendritic branching, spinal morphogenesis, stress coping, 5-HT2A receptor

Disclosure:BetterLife Pharma: research contract (own)

Nasser Haddjeri, Bence Farkas, Béla Kiss, Viktor Román, Balázs Lendavi, Nika Adham*

Abbvie, Madison, New Jersey, USA

Background:Anxiety symptoms are common in patients with schizophrenia, bipolar I disorder, and major depressive disorder, underscoring the need for treatments that can address the complex symptomatology of these disorders. Cariprazine is a D3/D2 receptor partial agonist that, in addition to its dopaminergic effects, preferentially affects dopamine D3 receptors approved by the US Food and Drug Administration for the treatment of adults with schizophrenia, manic, mixed, and depressive episodes associated with a bipolar disorder. I, cariprazine also acts as a partial agonist at serotonergic 5-HT1A receptors implicated in the development of anxiety symptoms. The aim of this study was to evaluate the anxiolytic effects of cariprazine in rats tested alone and in combination with two clinically used anxiolytics: the selective serotonin reuptake inhibitor (SSRI) escitalopram and the benzodiazepine diazepam.

Methods:Anxiety-like symptoms were tested using an electroshock-induced ultrasonic vocalization (USV) model in male Wistar-Unilever rats (150-200  g). The test device was a 20 cm x 20 cm x 25 cm chamber equipped with a grid floor through which foot shocks (1 mA; 4 s) could be delivered. Day 1 consisted of two 10-minute sessions, with a 60-minute interval, in which the rats received 1 to 4 randomly spaced electrical shocks until USV emission was detected. The next day, the rats were placed in the chamber and received a single shock (10% 2-hydroxypropyl-β-cyclodextrin saline solution; i.p.) 30 min after vehicle injection. On day 3, the test was performed 30 min after i.p. repeated. Injection of cariprazine (1, 5, 50, 100, or 300 mcg/kg), escitalopram (0.2, 1, or 3 mg/kg), or diazepam (1, 3, or 6 mg/kg). In a second experiment, subeffective drug doses (determined in the first experiment) were administered alone or in combination 30 minutes before the day 3 test. UPSs were defined as vocalizations with frequencies greater than 20 kHz. For both experiments, the duration of the USVs on each test day was determined using the 5-minute period starting immediately after the first shock-induced USV. For analysis, USV durations were converted to a percentage of the USV duration after vehicle treatment on day 2.

Results:Cariprazine treatment reduced the duration of secretion-induced VUS in the feet in a dose-dependent manner. Compared to vehicle, significantly shorter durations of USV were observed at doses ≥50 μg/kg (p<0.05) and USVs were eliminated at the dose of 300 μg/kg (p<0.001). Dose-dependent decreases were also observed for escitalopram and diazepam and were statistically significant versus vehicle at doses ≥1 mg/kg (P<0.001) and ≥3 mg/kg (P<0.05), respectively. At the highest doses tested, the maximum reduction in UPS duration relative to vehicle was 89% with escitalopram and 55% with diazepam. Higher doses of diazepam resulted in unclear sedative effects, making it difficult to determine specific anxiolytic effects. In the second experiment, combined treatment with subeffective doses of cariprazine (1 µg/kg) and escitalopram (0.2 mg/kg) reduced the duration of footshock-induced EV by 42% compared to vehicle (P<0.001 ), while combined treatment with subeffective doses of cariprazine (5 μg/kg) and diazepam (1 mg/kg) resulted in a 26% reduction (P<0.01 vs. vehicle).

Conclusions:In a model of USV induced by rodent foot shock, cariprazine exhibited potent anxiolytic activity similar to that of the SSRI escitalopram and the benzodiazepine diazepam. Synergistic anxiolytic-like effects have been observed for cariprazine used in combination with escitalopram or diazepam at subeffective doses of each compound. Although more research is needed to understand the mechanisms underlying these synergistic effects, regimens containing cariprazine, alone or in combination with low-dose anxiolytics, may be effective in treating persistent anxiety disorders or anxiety associated with schizophrenia.

Key words:Cariprazine, dopamine, 5-HT, anxiety, ultrasonic vocalization model (USV)

Disclosure:AbbVie: Employees (own)

Hiroyuki Koike*, Ichiro Horinokita, Mikio Suzuki, Takashi Futamura

Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan

Background:Classic serotonergic psychedelics have sparked renewed interest in clinical and preclinical settings because of their robust antidepressant and anxiolytic responses after a single dose. As a result, understanding mechanisms of action has been an area of ​​great interest in basic research. Recent studies emphasize the importance of 5-HT2A receptor agonism for the therapeutic effects of psychedelics, although the exact mechanism remains unclear. Relevant and useful animal models are needed to gain a better understanding of the behavioral outcomes and biological correlates associated with the antidepressant and anxiolytic effects of psychedelics, particularly through 5-HT2A receptor activation. In this study, we examined the behavioral effects of a potent 5-HT2A receptor agonist, TCB-2, on corticosterone-induced anhedonia and the Novity Suppressed Feeding Test (NSFT) to assess the potential usefulness of these models for preclinical psychedelic research.

Methods:Male C57BL/6J mice were used for this study. We treated the mice with corticosterone to induce anhedonia, which was observed as a decreased preference for sucrose. The NSFT was performed in naïve mice to measure anxiety-induced hypophagia. To evaluate the antidepressant and anxiolytic effects of TCB-2 in these assays, we injected mice intraperitoneally 24 hours before the test. To assess hallucinogenic potency, we measured the head twitch response immediately after administration. The experiments used 6-8 mice per treatment. Data were analyzed by one-way ANOVA followed by Dunnett's post hoc test (p < 0.05 was considered statistically significant).

Results:TCB-2 enhanced the chronic corticosterone-induced decrease in sucrose preference; the response was greatest with an intermediate dose (0.1 mg/kg), but decreased slightly with higher doses. The TCB-2 also reduced latency until the NSFT is powered up. The effective doses of TCB-2 in these behavioral studies elicited the head twitch response.

Conclusions:We show that TCB-2 exerts antidepressant and anxiolytic effects after a single injection in a behavioral model of anhedonia, a sucrose preference test in mice treated with corticosterone, and an anxiety model, NSFT. As traditional antidepressants are effective in these models after chronic treatment, our results suggest that the onset of action of TCB-2 is rapid. Furthermore, as the effects of TCB-2 were observed 24 hours after treatment and psychedelics promote long-lasting neuronal plasticity through 5-HT2A receptor activation, it is likely that TCB-2 in effective doses promotes induced neuronal plasticity, possibly mediated by an antidepressant - and anxiolytic effects through the same mechanism as psychedelics. Future work that leads to a precise delineation of the mechanisms underlying the observed effects of TCB-2 is needed to identify and develop an effective treatment to alleviate symptoms of depression and anxiety, and the behavioral models we use may be helpful in discerning robust effects. of psychedelics and elucidate the mechanisms of their action.

Key words:5-HT2A Serotonin Receptor, TCB-2, Psychedelics, Animal Models

Disclosure:Nothing to disclose.

Michael Palfreyman*, Joan Krakowsky, Michael Morgan, Clinton Canal, Pradip Pathare, Ken Avery, Amy Reichelt, Joshua Hartsel, Alex Nivorozhkin, Amir Inamder, Geoffrey Varty

Palfreyman BioPharm Advisors, Inc., St. Petersburg, Flórida, EUA

Background:Phase 2 clinical trials have shown that short-term administration of psilocybin has positive effects in major depressive disorder (MDD) and treatment-resistant depression (TRD). Although psilocybin is potent and inherently safe, there are significant differences between patients in their experiences with psychedelics and side effects. This variability is likely due to psilocybin acting as a prodrug, requiring dephosphorylation for the psychoactive metabolite psilocin. CYB003 is a new deuterated psilocybin analogue that may offer advantages over psilocybin. The purpose of these studies was to compare the in vitro and in vivo activity of CYB003 with psilocin and to perform new drug clearance (IND) studies to allow initiation of clinical trials.

Methods:The pharmacological profiles of CYB003 and psilocin were compared by functional and serotonin (5-HT) receptor binding assays to assess potency, potency, and selectivity at serotonin receptors; both compounds were also tested for activity on a panel of over 100 proteins. Furthermore, both compounds were evaluated in the HTR (Mouse Head Twitch Response) test (a behavioral model of psychedelic effects). ADME and pharmacokinetic (PK) studies have also been completed, followed by dose ranging studies in rodents and non-rodents. Finally, IND qualification studies carried out in accordance with Good Laboratory Practice (GLP) standards were completed; specifically, repeated-dose toxicology studies and pharmacological assessments of cardiovascular, respiratory, and CNS safety.

Results:The pharmacological and selectivity profile of CYB003 was similar to that of psilocin. CYB003 binds and activates the 5-HT2A receptor (5-HT2A Ki: 37 nm; psilocin 31 nM) and induces HTR in mice (HTR count (0-30 min): CYB003 8.9 _+ 1.3; psilocin 12.6+_1). ADME studies indicate low in vitro metabolism and PK/PD studies have shown a good correlation between plasma levels and in vivo activity. Results from the safety pharmacology study were consistent with activation of 5-HT receptors and mirrored results seen with other psychedelics, including psilocybin. LPG toxicology studies have identified safe and potentially effective doses and will support multiple dose clinical studies. Together, these data allowed the initiation of phase 1/2A clinical trials.www.ensayosclinicos.govID: NCT05385783: A study of a psilocybin analogue (CYB003) in participants with major depression. Phase 1/2A protocol in participants with MDD is ongoing (Clinilabs, Eatontown, NJ).

Conclusions:Our results confirm that CYB003 has the appropriate pharmacology and safety profile to proceed in clinical trials in patients with MDD. These data support the potential for CYB003 to have properties superior to psilocybin and provide significant clinical benefits.

Key words:Psychedelics, psilocybin analogues, pharmacology, GLP studies allowing IND, major depressive disorder

Disclosure:Cybin, Inc.: Employees (I), Palfreyman BioPharm Advisors, LLC: Owner (I)

Amir Inamdar*, Michael Morgan, Joan Krakowsky, Amy Reichelt, Clinton Canal, Tina Mueller, Ken Avery, Pradip Pathare, Joshua Hartsel, Alex Nivorozhkin, Geoffrey Varty, Michael Palfreyman

Cybin, London, United Kingdom

Background:Phase 2 clinical trials have shown that short-term administration of psilocybin has beneficial effects in a variety of psychiatric disorders, including major depressive disorder (MDD), anxiety, and substance use disorders. Although psilocybin is potent and inherently safe, the literature shows that there is significant variation between patients in their experiences with psychedelics and side effects. This variability is likely due to psilocybin acting as a prodrug, requiring dephosphorylation for the psychoactive metabolite psilocin. After being metabolized, psilocin is absorbed into the bloodstream and crosses the blood-brain barrier to interact with central serotonergic receptors, including 5-HT2A receptors. Improving the absorption, distribution, and elimination of psilocybin while maintaining its therapeutic effects can provide significant patient benefits. CYB003 is a deuterated psilocybin analogue that may provide such benefits. The purpose of these studies was to compare the pharmacokinetic (PK) profile of CYB003, a new psilocybin analogue, with psilocybin and psilocin.

Methods:To compare the pharmacokinetic profile, CYB003, psilocin and psilocybin were orally administered to male Sprague-Dawley rats. Plasma and brain samples were collected over a 4 hour period after dosing and analyzed for CYB003 and psilocin levels by LC-MS/MS. The pharmacokinetic profiles of CYB003 following oral and intravenous administration in mice, rats and dogs were also determined. Pharmacokinetic parameters were determined by non-compartmental analysis.

Results:CYB003 shows potential advantages over psilocybin in terms of its plasma pharmacokinetic profile. Compared to psilocybin, the rat plasma exposure profile of CYB003 has a shorter time to peak effect, a shorter half-life (T1/2) and, most importantly, less variability. The time to reach peak plasma exposure (Tmax) was 30 minutes for CYB003 compared to 60 minutes for plasma psilocin after psilocybin administration. The half-life (T1/2) for CYB003 was 45 min compared to more than 240 min for psilocin from psilocybin and was confirmed by a 36% reduction in CYB003 MRI. Furthermore, the between-subject variability of CYB003 in maximum plasma concentration (Cmax) achieved was reduced by 53% compared to psilocybin and psilocin. The rank order of oral bioavailability (%F) between species was mouse=dog»rat. The brain-to-plasma ratio of CYB003 in the rat after IV administration was 11.5 compared to 8.1 for psilocybin compared to psilocybin, indicating better CNS penetration and therefore potential to increase the systemic dose of CYB003 needed to achieve a target therapeutic level in the brain. This trend was also observed in mice.

Conclusions:These results suggest that the unique PK properties of CYB003 offer a significant advantage over psilocybin for the treatment of a variety of psychiatric disorders, including MDD.

Key words:Psychedelics, pharmacokinetics, major depressive disorder, psilocybin analogue, psilocin

Disclosure:Cybin: Staff (Own), Astrazeneca: Staff (Own)

Georgette Suidan, Galen Missig*, Sokhom Pin, Srinivas Chakilam, Sridhar Duvvuri, Philip Iredale

Cerevel Therapeutics, Cambridge, Massachusetts, EUA

Background:Kappa opioid receptors (KORs) have potent activity in many important brain regions whose activity defines psychological phenomena including reward motivation or addictive substances and anxiety. As regulators of cellular excitability and synaptic transmission of key circuits involved in reward and mood, KORs represent a unique therapeutic target for clinical investigations for the treatment of major depressive disorders and substance use disorders.

Methods:In vitro pharmacological studies were performed to assess the binding affinity and functional antagonism (cAMP) of CVL-354 at human KOR and human mu-opioid receptor (MOR). Pharmacokinetic studies were performed in mice and non-human primates to determine brain penetration. Target engagement studies were performed in mice to examine the relationship between drug exposure and CVL-354 occupancy in mKOR and mMOR and to determine in vivo selectivity. Opioid-induced thermal sensitivity, as measured by the tail-wagging assay, was used to determine pharmacological selectivity for mKOR over mMOR in vivo. Finally, CVL-354 reversal of KOR agonist-induced motivational deficits was measured in the progressive ratio response task.

Results:In vitro binding data showed that CVL-354 has a 31-fold higher binding affinity for hKOR than for hMOR, indicating selectivity for KOR. Furthermore, CVL-354 was found to be an antagonist at KOR (IC50 =  0.042 nM) and MOR (IC50 =  9.1 nM) and, more importantly, lacks agonist activity at both receptors up to 1 μM (0, 01 nM - 1 µM ) showed tested). Pharmacokinetic studies in mice, rats and non-human primates have demonstrated that CVL-354 penetrates the brain and have suggested increased brain penetration in higher species. In vivo target interaction studies in mice showed a 27-fold greater selectivity for KOR (IC50=2.2 nM) over MOR (IC50=59.7 nM), similar to in vitro binding studies in humans. The thermal sensitivity test (tail wag) was used to demonstrate functional antagonism in both KOR and MOR of analgesia (p<0.05) and, although qualitative, indicated ~10-fold pharmacodynamic selectivity. Finally, the effects of CVL-354 on the progressive ratio response were evaluated. Administration of the KOR agonist spiradoline in mice induces an anhedonic-type phenotype, in which the animals are less motivated to seek rewards in the progressive ratio paradigm (p < 0.05). CVL-354 dose-dependently reversed the effects of spiradoline on motivation (ED50=0.09 mg/kg, ~2 nM). A one-way ANOVA (Fast Ratio Response and Progressive Ratio) was used and Dunnett's post-hoc tests were performed to compare treatment with control groups, where appropriate.

Conclusions:In vitro and in vivo pharmacological assays have demonstrated that CVL-354 is a new potent and selective kappa opioid receptor (KOR) antagonist that penetrates the brain. Furthermore, CVL-354 reverses motivational deficits induced by KOR agonists.

Key words:Kappa-Opioidrezeptor, Kappa-Opioidrezeptorantagonist, Motivation, Anhedonia

Disclosure:Cerevel Therapeutics: Employees, Stocks/Equity (Equity)

Krista Wartchow*, Giselli Scaini, Tina Li, Giovana Zunta-Soares, Rodrigo Machado-Vieira, Jair Soares, João Quevedo

UTHealth Science Center, Houston, Texas, USA

Background:One of the leading hypotheses is that the pathology of bipolar disorder is due in part to the failure of mitochondrial function to support adequate neurotransmission and synaptic plasticity, thereby impairing mood regulation, memory, and executive function. Several studies support this hypothesis, showing that patients with BD have atypical mitochondrial metabolism, oxidative stress and mitochondrial DNA (mtDNA) damage. Furthermore, studies of primary mitochondrial diseases have shown a high prevalence of self-reported affective syndromes. Plasma fibroblast growth factor 21 (FGF-21) is an established biomarker for mitochondrial disease.

Methods:In this pilot study, we included 31 healthy controls and 34 TB patients (11 TB euthymic and 13 TB depressed). All subjects underwent a comprehensive clinical interview and diagnosis of TB and TRD according to the DSM-IV-TR. Mood symptoms and functional status were assessed using the Montgomery Asberg Depression Scale (MADRS), Youthful Mania Rating Scale (YMRS), Global Assessment of Functioning (GAF), and Brief Operational Assessment Test (FAST). Quantitative analysis of plasma FGF-21 levels was performed using a commercial kit.

Results:Unidirectional ANCOVA after controlling for age, sex, BMI, race and smoking showed that plasma FGF-21 did not produce statistically significant results among patients with BD and CH. However, after stratifying patients into depressed and euthymic patients, we found that depressed TB patients have higher FGF-21 levels compared to euthymic TB patients. Another notable finding was that plasma levels of FGF-21 predicted changes in depression rating scale and functional status.

Conclusions:Taken together, our results suggest that elevated plasma FGF-21 may act as a mood marker in BD. Furthermore, our results confirm previous studies and support the notion that mitochondrial dysfunction plays a role in the pathophysiology of BD and may play a role in clinical and functional outcomes.

Key words:Mitochondria, Bipolar Disorder, FGF-21, Bipolar Depression

Disclosure:Nothing to disclose.

Camila De Carvalho-Lima*, Emese H. C. Kovács, Alexandra Del Favero-Campbell, Alexandre Paim Diaz, Salahudeen Mirza, Consuelo Walss-Bass, Benney M. R. Argue, Joao Quevedo, Jair C. Sores, Marie E. Gaine, Gabriel R. Fries

UTHealth Houston, Houston, Texas, United States

Background:Bipolar disorder (BD) is associated with reduced life expectancy, with excess mortality from almost all categories of natural causes. Suicide is a leading cause of death in TB, and a history of suicide attempt has been associated with lower life expectancy and worse clinical outcomes. Although the risk of suicide in tuberculosis is high, excess mortality is mainly explained by somatic comorbidities, with recent studies suggesting that premature cellular senescence contributes to lower life expectancy in psychiatric disorders. Thus, this premature mortality can be explained by observations that BD is associated with age-related changes in biomarkers of inflammation, oxidative stress, epigenetics and metabolism. In this study, we examined the acceleration of GrimAge, a new epigenetic clock trained on time-to-death data and uniquely associated with mortality and life expectancy and its subcomponents in TB patients with and without a history of TB-associated suicide attempt. 🇧🇷

Methods:A discovery cohort (Houston) included TB patients with no previous suicide attempt (BD/non-SA, n=66), TB patients with a lifetime history of suicide attempts (BD/SA, n=77), and healthy controls (HC, n=51) matched for age, sex, and race. A GrimAge acceleration index (AgeAccelGrim) was calculated based on genome-wide DNA methylation (mDNA) in peripheral blood, measured with the Infinium MethylationEPIC Beadchip (Illumina) and the chronological age of all participants. ANCOVA models were used to compare groups for AgeAccelGrim as well as packs of smokers based on mDNA and seven age-dependent plasma proteins (adrenomedullin, beta-2-microglobulin, cystatin C, growth differentiation factor 15 (GDF-15 ) B. leptin , Plasminogen Activation Inhibitor 1 (PAI-1) and Tissue Metalloproteinase Inhibitor 1). The results of patient-specific comparisons were independently validated in a repeat cohort (Iowa), including BD/non-SA (n=47) and BD/SA (n=47).

Results:In the discovery cohort, HC, BD/non-SA, and BD/SA differed significantly for AgeAccelGrim after controlling for age, gender, population genetic stratification, years of schooling, body mass index, smoking, and blood cell count (F (2.175 ) = 7.864, p < 0.001), with the highest AgeAccelGrim found in BD/SA, with excess 3-year mortality compared to HC (p = 0.001). BD/SA also showed a significantly greater AgeAccelGrim than BD/non-SA in the unadjusted model (P=0.002) and after adjusting for covariates in the discovery cohort (P=0.027). Furthermore, this difference between groups was also replicated in an independent cohort in unadjusted (P =0.02) and adjusted (P <0.001) models. Finally, unadjusted models in the discovery cohort showed that BD/SA had significantly higher mDNA-based PAI-1 levels (P=0.019) and pack-years (P=0.029) compared to HC. After adjusting for covariates, BD/SA showed significantly higher PAI-1 (P=0.016), pack years (P=0.022) and GDF-15 (P=0.035) scores compared to HC.

Conclusions:The epigenetic acceleration of GrimAge may contribute to premature morbidity and mortality in tuberculosis patients with a lifetime history of suicide attempts. These results are combined with existing evidence that not only BD but also suicide attempts may be associated with an acceleration of biological aging and provide putative biological mechanisms for premature mortality in these diseases (e.g., through the action of the PAI-1 and GDF). -fifteen). Future studies are needed to examine the role of epigenetic aging in the pathophysiology of BD and suicidal behavior and to analyze their unique and shared biological underpinnings.

Key words:Bipolar Disorder, Suicide Attempt, Accelerated GrimAge

Disclosure:Nothing to disclose.

Masataka Wada*, Shinichiro Nakajima, Shiori Honda, Mayuko Takano, Keita Taniguchi, Yu Mimura, Sakiko Tsugawa, Masaru Mimura, Yoshihiro Noda

Keio University Faculty of Medicine, Sinuku-ku, Japan

Background:One-third of patients with depression do not respond to optimal antidepressant treatment, which is defined as treatment-resistant depression (TRD). Recent studies have established the benefit of ketamine for TRD, and the abnormal levels of glutamatergic neurometabolites in TRD suggest that abnormalities in glutamatergic neurotransmission are involved in the pathogenesis of TRD. Furthermore, a recent lesion network mapping study reported that the symptom network of depression may involve the dorsolateral prefrontal cortex (DLPFC), where transcranial magnetic stimulation (TMS) treatment is also effective in ESRD. The paradigm of intracortical facilitation (ICF) with a combined method of TMS and electroencephalography (TMS-EEG) primarily allows the assessment of neural function mediated by the N-methyl-D-aspartate receptor in target regions of the brain. The objectives of this study were 1) to compare glutamatergic neuronal activity as indicated by the ICF paradigm in the DLPFC between TRD patients and healthy controls (HC) using TMS-EEG, and 2) to investigate connections between cell-specific glutamatergic gene expression and abnormalities in glutamatergic neuronal activity in TRD using a virtual histological approach.

Methods:This study was approved by the Keio University School of Medicine Ethics Committee and the registration number of this study is UMIN000028863. Sixty TRD patients and thirty HCs received 80 single-pulse and pair-pulse TMS with an interstimulus interval of 10 ms on the left DLPFC to measure evoked potential. The degree of ICF was determined using the difference between single-pulse and pair-pulse evoked potentials. Differences in ICF between the TRD and HC groups were calculated using group-based permutation analysis. In addition, we calculated cross-regional profile correlations between altered glutamatergic neuronal activity and glutamate-related gene expressions derived from the Allen Human Brain Atlas dataset.

Results:The ICF level at the electrode sites above the left DLPFC was not significantly different between the two groups; however, the ICF level in the left DLPFC, just below the TMS coil, was reduced compared to that of the HCs (p = 0.014). Furthermore, the brain surface distribution of decreased ICF levels was correlated with the brain surface distribution of specific glutamate-related gene expression (p = 0.016).

Conclusions:A reduced ICF level in the left DLPFC represents a pathophysiological endophenotype of TRD and may be associated with glutamate-related gene expression.

Key words:TMS-EEG, Glutamate, Treatment-Resistant Depression, Imaging-Genetics

Disclosure:Nothing to disclose.

Mark Kvarta*, Yizhou Ma, Si Gao, Heather Bruce, Joshua Chiappelli, Peter Kochunov, Elliot Hong

University of Maryland School of Medicine, Maryland Psychiatric Research Center, Catonsville, Maryland, USA

Background:Depression is very common in people with neurological disorders, particularly epilepsy, migraines, multiple sclerosis, and stroke, with lifetime rates of depression after the onset of a neurological disorder of up to 50%. Comorbidities between depression and neurological stroke are well described, although data on the neurobiological basis are lacking. Major depressive disorder (MDD) defined by the DSM is associated with well-replicated structural brain changes, for example, reduced volumes in the frontal cortices and hippocampus, while the neurobiological origin of depressive disorder due to another medical condition (including neurological diseases) is poorly understood it is rarely studied rigorously.

If biophysical aspects of brain function contribute to MDD, then a neurological disorder may alter brain structures in ways similar to patterns associated with MDD as a system-level neurobiological explanation for why some neurological patients develop symptoms. Using neuroimaging and longitudinal behavioral data from the UK Biobank (UKBB) and applying a Regional Vulnerability Index (RVI) to quantify individual whole-brain phenotypic similarity to MDD (RVI-MDD), we tested the hypothesis that an insult produces neurological changes in the brain can cause changes similar to the patterns of deficits seen in MDD to increase the risk of depressive symptoms.

Methods:The UKBB is a large prospective study to identify determinants of health in middle and old age. We used data from two UKBB visits: the initial assessment visit (v0) and the second brain imaging visit (v2). A continuous measure of depression symptomatology obtained at v0 and v2 was obtained using the Recent Depressed Example-4 (RDS-4) scale, a measure validated for neuroimaging studies within the UKBB with questions addressing the various MDD criteria (Dutt et al ., 2022). The RDS-4 shows a high degree of agreement with other scales such as the PHQ-9 when collected simultaneously, with the advantage that the RDS-4 questions were collected on repeated visits to the UKBB, even when data were collected from images. The total score for depressive symptoms at each visit was the sum of the responses given (including up to 1 imputed missing score). 46,910 UKBB participants (51.3% female) answered at least 3 of the RSD-4 questions about depressive symptoms at both visits and were enrolled. We identified individuals with a new report of neurological disease between v0 and v2, a prospective approach in which data from v0 before the onset of neurological disease (IN) can be considered as baseline. The list of neurological diagnoses included infections, multiple sclerosis, epilepsy, migraine, intracerebral hemorrhage, and stroke.

Imaging data were taken from UKBB Neuroimaging Data Release Version 1.6. RVI calculations require large image samples aggregated from disease-independent imaging studies to establish their “gold standard”, here using data from the ENIGMA consortium for MDD. The UKBB phenotypes included 24 regional white matter tract FA values, 33 regional estimates of cortical gray matter (GM) thickness, lateral ventricular volumes, and 7 subcortical gray matter volumes per hemisphere corresponding to these derivations of the UKBB workflows. PUZZLE. RVI-MDD scores were calculated using “RVIpkg” in [R]. After covariate regression, image phenotypes were transformed into z-scores and Pearson's correlation coefficient between a participant's z-scores and corresponding effect sizes for differences from the control group of patients with MDD from the ENIGMA consortium for MDD ( Schmaal et al., 2017 ). 🇧🇷

Results:In the first validation of RVI-MDD in UKBB data outside of neurological disorders, we found that people with MDD had greater cortical RVI-MDD compared to those without MDD (p = 4 × 10-7). In the non-neurological control (NC) group, those with increased depressive symptoms between visits had a higher RVI-MDD than those without mood deterioration (p = 3 × 10-6). Thus, cross-sectional and longitudinal data supported the validity of applying the RVI-MDD-derived cortical deficit pattern to UKBB depression symptom data.

There were no significant differences in the proportion of age and sex between the NI group (n = 890) and the NC group (n = 46,020). NI had higher RDS-4 depression scores at v0 before the onset of neuroillness compared with NC (p = 4 × 10-7), while NI and NC showed reduced depression from v0 to v2 (p = 3 × 10-15 ). A greater proportion of subjects in the NI group reported worsening depression scores (30.8%) than in the NC group (24.9%) at v2 (p=6×10-5). Among newborns, the RVI was higher for those with worsening depressive scores than for those without worsening (p=0.021). In a full 2×2 ANCOVA model, there was a significant interaction between group switching and depression (F(1.35550)=4.02, p=0.045). NI with worsening depression had the highest RVI-MDD, supporting that RVI can segregate NI by depression score status. In comparison, the polygenic risk score for MDD was not different between the NI and NC groups (p = 0.70).

Conclusions:This study shows longitudinal quantitative changes in mood scores before and after major neurological events and that these changes lead to shifts in cortical deficit towards an MDD-like brain pattern. People with neurological impairment during the study period who reported worsening depression scores had a higher RVI than those who did not. These data add new neurobiological insights into the etiology of depression after neurological illness. RVI for MDD may provide a biomarker to index those likely to develop depression associated with neurological disorders.

Key words:Human neuroimaging, brain markers for depression, neurological disorders, depression, big data

Disclosure:Nothing to disclose.

Charles Conway*, Peter Nagele, Thomas Zeffiro, Britt Gott, Thomas Nguyen, Charles Zorumski, Ben Julian Palanca

Washington University School of Medicine, Saint Louis, Missouri, USA

Background:Nitrous oxide (N2O), an N-methyl-D-aspartate (NMDA) receptor antagonist with similarities to ketamine, has shown promise as a therapeutic in treatment-resistant major depression (MDRD) and PTSD. Similar to ketamine, the antidepressant effects last well beyond a single hour-long inhalation. Previous studies have shown that changes in electroencephalographic signals and altered brain networks occur during N2O inhalation. Notably, electroencephalographic studies of ketamine in depressed patients show persistent plasticity changes in the occipital cortex. This brain imaging assay examines subacute and persistent changes in brain network connectivity 2 hours and 24 hours after a 1-hour exposure to inhaled N2O using resting-state functional magnetic resonance imaging (rs-fMRI).

Methods:Sixteen healthy male and female volunteers were recruited for a double-blind crossover study. Subjects underwent random inhalation sessions of 50% nitrous oxide/oxygen or an oxygen/air mixture for one hour. Three rs-fMRI scans were obtained 10 minutes before inhalation and 2 hours and 24 hours after the inhalation sessions. Based on literature support for involvement in mood disorders, four canonical a priori network seeds were selected: default mood, dorsal attention, affect, and reward networks. Interregional rs-fMRI correlations were measured using echoplanar imaging. Interregional correlations were calculated and converted from time series of preprocessed time series data to Fisher z scores, adjusted for motion artifacts, and regressed for interfering covariates. To avoid bias caused by matrix testing, false detection rate (FDR) corrections were used. First-level whole-brain modeling estimated the change in connectivity strength (before and after N2O) for both local connectivity strength using the local correlation metric (LCOR) and global connectivity strength using a metric of global correlation (GCOR). Seed-based functional connectivity was subsequently used to characterize the spatial pattern of connectivity changes associated with areas showing changes in LCOR and GCOR. Second-level modeling (before and after N2O) based on the first-level model results used a mixed-effects repeated measures model with replication, session, condition, and fixed effects as random effect, with the selected element as the view main. Bark as sown region.

Results:In comparisons before and after nitrous oxide inhalation, the canonical networks selected a priori did not show significant changes in functional connectivity from the resting state. However, exploratory whole-brain analyzes showed that N2O inhalation was associated with statistically significant changes in global brain connectivity compared to placebo, which persisted in the occipital cortex at 2 and 24 hours after inhalation (p-FDR =0.019). . Furthermore, second-level modeling in 200 gray matter regions showed stronger post-N2O correlations with bilateral insula, lateral parietal and middle cingulate regions, and bilateral cerebellar regions (all p<0.05, FDR corrected with region-based statistics ). Furthermore, analysis of the resting state networks showed a strong strengthening of connectivity between the regions of the visual network and those of the dorsal attentional network, both 2 and 24 hours after inhalation (cluster TFCE = 55.94p = 0.041).

Conclusions:N2O inhalation in healthy volunteers has shown a sustained increase in global connectivity between primary visual cortex regions and the dorsal attention network. These results suggest that N2O inhalation induces cortical neurophysiological changes for at least 24 hours and are consistent with reports of synaptic plasticity in ketamine-induced visual networks. The sustainability of these findings is compelling, as they are consistent with the observed clinical results of the antidepressant N2O, as well as previous studies of neuronal plasticity with ketamine, suggesting that these NMDA antagonists may cause their antidepressant effects, in part, by persistently altering the connections of network in the visual. and attentional domains. More brain imaging studies of N2O in depression are needed.

Key words:Nitrous oxide, antidepressants, functional connectivity, networks, NMDA

Disclosure:Nothing to disclose.

Stephen Heisig, Jacob Dahill-Fuchel, Patrick Riva-Posse, Christopher Rozell, Allison Waters, Helen Mayberg

Icahn School of Medicine at Mount Sinai, New York, New York, United States of America

Background:Major depressive disorder affects approximately 14.8 million adults in the United States (Kessler et al., 2005). Although most cases of depression are treatable, up to 10% of patients do not respond to traditional interventions involving various combinations of medication, psychotherapy, and somatic treatments, including ECT. Deep brain stimulation (DBS) of the subcallosal cingulate white matter (SCC) is an emerging treatment strategy for this treatment-resistant depression (TRD), with published studies demonstrating sustained long-term antidepressant effects in 73% of patients. farce 2018).

Although long-term effects are generally sustained once achieved, clinical observation and evaluation and local electrophysiological recordings of LFP in SCC (Alagapan et al., 2021) indicate that recovery appears to have several phases: depression (defined as <50% Hamilton's alteration); good at onset (acute behavioral effects in the operating room); rough (improved but unstable); and good (>50% on the Hamilton Depression Rating Scale). These changes occur with a variable time course between individuals. Here, we tested whether the resting EEG shows changes comparable to the LFP and previously observed behavioral changes.

Methods:EEG was recorded in two cohorts of TRD patients receiving chronic DBS-SCC with two DBS systems: Medtronic Activa PC + S r (n = 8) and Medtronic Summit RC + S (n = 5). All patients were examined at 8 time points: before DBS implantation surgery; 4 weeks postoperatively with no ongoing DBS; once a month for 6 months during active stimulation. Recordings consist of 5-minute resting EEG data (EGI, 256 channels) with eyes open and closed acquired with bilateral stimulation turned on and off.

Time-frequency domain analyzes of resting EEG data over time were initially performed in 3-second windows using Thomson's multitaper method (5 cones) and mean power over 5 frequency bands (θ: 4–8 Hz, α: 8–12 Hz, low β: 12-20 Hz, high β: 20-30 Hz, and γ: 30-50 Hz) were calculated and compared across time points.

To track the course of recovery time, we gathered spectral information from a subset of the 256 channels and tracked the percentage of the "good" group (from the last 6-month visit) compared to all other time points. We then compared this time course with transitions defined by a neural network classifier used to discriminate SCC-LFP dynamics reflecting differences in clinically defined "depressed" and "good" states.

Results:Changes in EEG performance over time indicate that there are band-specific early (1 month) and late (2-6 months) differential changes in the first group of PC+S patients (two-group test, P ≤ 0.05 ). These are similar to periods reported in PET and LFP studies within the same patient group. EEG spectral findings are replicated in the second cohort. The topographic diagrams show different patterns of power changes in each frequency band: alpha and low beta frequency changes are located in the parietal/occipital canals, while beta power increases are located more centrally around Cz. The spectral clustering transitions on the resting EEG from "sick" to "good" occur at similar times to transitions in the LFP classifier.

Conclusions:These results demonstrate that resting EEG can identify distinct patterns of early and late response changes in the course of successful treatment of SCC DBS for TRD. The reaction pathway over 6 months includes 3 to 4 specific brain state transitions. The similarity of the bad-to-good transitions identified by the EEG with those previously identified in the SCC-LFP recordings suggests a non-linear evolution of SCC cortical network changes over time with sustained DBS. These results invite further consideration of the role of serial resting EEG in identifying treatment milestones that may guide treatment optimization.

References:

1. Kessler et ai. Arch Gene Psychiatry, 2005. 62:593-602.

2. Riva-Posse et al. Mol Psychiatry, 2018. 23: 843-849

3. Alagapan et al. Brain Initiative Poster, 2021

Key words:Brain-based markers for depression, deep brain stimulation, quantitative electroencephalography (qEEG)

Disclosure:Nothing to disclose.

Andreas Wulff, Scott Thompson*

University of Colorado School of Medicine, Aurora, Colorado, USA

Background:Depression is a devastating and widespread mental illness. Rodent models are widely used to understand the neurobiology of depression and to test potential new antidepressant drugs. As chronic stress is an important risk factor for the development of depression in humans, it is often used to induce depression-like behaviors in rodents. A wide range of behavioral outcomes are used to measure cognitive, rewarding, and other impairments following chronic stress. Among them is the sucrose preference test, which is used to measure an anhedonic phenotype after chronic stress. However, sex was largely neglected as a biological variable in these rodent experiments, and it remains unclear how the drinking behavior of male and female mice during the sucrose preference test is related to the hedonic state.

Methods:We used a custom home cage lycometry setup to record the drinking behavior of male and female C57Bl6 mice subjected to a sucrose preference test (n = 8-17 by group and sex). We analyzed changes in alcohol consumption during the night and identified more "bursts" of alcohol consumption, which have been used in previous microstructural analysis studies of licking as a measure of palatability. We then perturbed the sucrose preference test by substituting 0.1% sucralose for 1% sucrose or subjecting the mice to acute stress or mild dietary restriction. Finally, we tested how drinking behavior affected people after chronic multimodal stress. In testing the effects of chronic stress, we supplemented the sucrose preference test with other behavioral tests for hedonic state, curiosity, and pain sensitivity.

Results:At baseline, male and female mice showed intermittent drinking behavior with increased alcohol consumption at the beginning and end of the dark phase of a 12:12 light:dark cycle. Male and female mice showed a strong preference for the 1% sucrose solution, as observed by the preference for consumed volume, higher consumption of bottled sucrose, and greater number and duration of ingestion episodes. The mice also showed a strong preference for calorie-free 0.1% sucralose, which was also reflected in the number of licks and the number and duration of licks. Neither acute stress nor mild dietary restrictions appeared to significantly affect drinking behavior in either male or female mice, but chronic stress resulted in a decrease in sucrose preference. By comparing the drinking behavior of male and female mice, we found that females drank more but at shorter intervals than males. Mice were also less prone to chronic stress, and males showed a marked decrease in alcohol consumption from the sucrose bottle. However, while male mice showed a marked decrease in the number of sucrose consumption episodes after chronic stress, session durations increased on both water and sucrose bottles, and the relative session durations did not alternate between sucrose and drinking water. from then on. chronic stress. This stress effect was also observed in female mice. However, in this cohort we also saw no impairment of other established hedonic or curious behaviors, but we did observe increased sensitivity to pain in male and female mice after chronic stress. Chronic stress also had an effect on alcohol consumption during phases with a stronger spike in consumption at the beginning of the dark phase, but no increase in consumption at the end of the dark phase.

Since the duration of consumption episodes is usually taken as a measure of the acute reward response to a palatable solution, our data indicate that a loss in sucrose preference after chronic stress may not be due to lack of reward response. Instead, we saw a decrease in the number of licking episodes, which may indicate dysfunctional metabolic or cognitive processes. What causes a loss of sucrose preference may depend on species, strain, and/or stressors.

Conclusions:Male and female C57Bl6 mice show a preference for sucrose, however, the microstructural drinking behavior is slightly different. Furthermore, we found that female mice were less prone to chronic stress than male mice. Finally, we found evidence that, under the conditions used in this experiment, altered sucrose preference after chronic stress may be due to cognitive or metabolic impairments rather than impairments in the reward response.

Key words:Reward deficit, anhedonia, stress

Disclosure:Terran Biosciences: Patent (Own), Scope: Patent (Own)

Serena Gumusoglu*, Michaela Kiel, Brandon Schickling, Kaylee Weaver, Marisol Lauffer, Hannah Sullivan, Kaylie Coulter, Yuping Zhang, Eric Devor, Donna Santillan, Mark Santillan

Carver School of Medicine da University of Iowa, Iowa City, Iowa, EUA

Background:Gestational hypertensive disorders such as preeclampsia have a high rate of comorbidity with mood and anxiety disorders, which in turn appear to increase the risk of preeclampsia by up to 3 times. This bidirectional risk suggests common mechanisms that may provide insight into potential treatment targets for these often dangerous disorders. Previous work by our group has shown that loss of RGS2, a risk gene for pre-eclampsia and psychiatric disorders such as anxiety, depression and suicide, leads to pre-eclampsia-like obstetric phenotypes such as gestational hypertension and placental dysfunction in a model of mouse. 🇧🇷 Here we investigate RGS2-mediated conserved mechanisms that may alter brain and vascular function to increase the risk of preeclampsia and psychiatric disorders, particularly in women.

Methods:Controls of adult RGS2 knockout (KO) and wild (WT) littermates (n = 6 by genotype and sex) were analyzed using Y-maze, open field, sucrose preference test, queue breaking, social approach and increase in behavior tested plus maze (EPM) studies. The brains of these animals were sectioned, half newly reserved for qPCR (dissected cortex, midbrain and hypothalamus/paraventricular nucleus) via qPCR, and half fixed in formalin and labeled with lectin IB4 (cerebrovascular marker), NeuN and DAPI . ImageJ and Stereology were used to calculate vessel and cell densities. Platelet-free plasma serotonin (5-HT) was measured by ELISA. Peripheral vascular dysfunction was analyzed in a separate cohort of animals (n = 3-7 by genotype and sex). Blood pressure was determined by tail cuff plethysmography (CODA) and the aortas were dissected and analyzed for redox and angiogenic factors by qPCR. Males and females were analyzed separately. PRISM was used for data analysis and presentation.

Results:Male RGS2KO mice showed hyperlocomotion (P=0.05), increased latency to explore (Y maze) (P=0.048) and impaired social memory (P=0.02). RGS2KO females showed a decrease in central exploration (P=0.05) and an increase in wrestling in the tail test (P=0.005). Male and female RGS2KO mice exhibited anxiety-like (EPM) and hedonic (increased preference for sucrose) behaviors (P = 0.04 and 0.02, respectively). RGS2KO mice also showed significant reductions in cortical vessel density (male P=0.05, female P=0.144). Cortical thickness, white matter, commissure thickness and cortical cell density did not change. Molecular profiling of cortex, midbrain, and hypothalamic/paraventricular nucleus by qPCR revealed a significant increase in cortical HTR2A (P = 0.006) and MAOA (P = 0.03) in females and hypothalamic SLC6A4 in males (P = 0.02). Peripheral plasma platelet-free 5-HT did not change by gender or genotype. In preliminary assessments, blood pressure also remained unchanged by gender or genotype. Aortic studies revealed a significant upregulation of NOX4 (P = 0.002) and HIF-1A (P = 0.04) in women and PDGFRb (men P = 0.07, women P = 0.05). MMP-9 was also significantly reduced in RGS2KO males (P=0.05).

Conclusions:Taken together, these results demonstrate that animals in RGS2KO exhibit sex-specific alterations in mood and other behaviors, expression of cerebral serotonergic genes, peripheral vascular redox and angiogenesis, and cell density of cerebral vasculature. Some of these results show specific vulnerabilities of women. The disorders we report are not caused by hypertension, but common vascular redox mechanisms and angiogenic dysregulation may underlie changes in brain and cerebrovascular and peripheral function. These mechanisms may also implicate the common pathogenesis of anxiety/depression with preeclampsia. This points to valuable future therapeutic targets and avenues for further mechanistic exploration.

Key words:Pregnancy, cardiovascular function, serotonin, depression and anxiety, angiogenesis

Disclosure:Nothing to disclose.

Susannah Tye*, J Blair Price, Adam Walker, Jennifer Kruse, Kathryn Cullen, Mark Frye, Lilly Schwieler, Sophie Erhardt

University of Queensland, St. lucia, australia

Background:Low-dose ketamine directly stimulates neurotrophic signaling to promote neuroplasticity and the antidepressant response. Despite a clear biological mechanism for target binding, moderating factors are not well understood. The present study examined the effects of inflammation on the response to ketamine in a preclinical rodent model of treatment-resistant depression.

Methods:Male Wistar rats (n=86) received adrenocorticotropic hormone (ACTH; 100 µg/day, 22 days), lipopolysaccharide (LPS; 750-1250 µg/kg, days 17-22) and/or saline as vehicle controls (0 .9% w/v, 22 days). Sucrose preference tests were performed on alternate days throughout this treatment. The animals received ketamine (10 mg/kg, in the last two days) before the free field and forced swimming (FST) tests to demonstrate an antidepressant effect. Prefrontal cortex (PFC) tissue was collected from post mortem animals for analysis of kynurenine, kynurenic acid (KYNA) and 3-hydroxykynurenine (3HK) by high performance liquid chromatography. Enzyme-linked immunosorbent assays (ELISAs) were used to measure protein levels in the PFC (i.e., mammalian target of rapamycin (mTOR), 5'-adenosine monophosphate-activated protein kinase (AMPK), and glycogen synthase kinase-3 α /β (GSK3α/β) Serum C-reactive protein (CRP) and corticosterone levels were determined by ELISA.

Results:Significant interaction effects (p = 0.0493) and treatment effects with LPS and ketamine (p = 0.0017) were observed on FST behavior throughout the period of immobility. In particular, in animals receiving ACTH + LPS + ketamine, a robust antidepressant response was observed that reduced the degree of immobility compared to ACTH controls (p = 0.0017) and in animals receiving ACTH + LPS (p = 0.0439) . Likewise, the immobility levels expressed by the animals treated with ACTH + ketamine were significantly lower than those of the controls with ACTH (p = 0.0027), but not with the animals treated with ACTH + LPS. No significant effect of ketamine treatment on immobility time was seen in saline-treated animals, and no group differences were seen on other measures of behavior. Animals treated with ACTH + LPS had significantly higher levels of prefrontal KYNA than animals receiving ACTH + LPS + ketamine (p = 0.0037) or ACTH controls (p < 0.0001). In contrast, animals treated with ACTH + LPS + ketamine had significantly higher kynurenine/KYNA ratios than animals treated with ACTH + ketamine (p = 0.0008) and animals treated with ACTH + LPS (p = 0.0001). . ACTH controls had higher levels of kynurenine/KYNA compared to animals treated with ACTH + ketamine (p = 0.0117) and animals treated with ACTH + LPS (p = 0.0014). Animals treated with ACTH + LPS also had significantly higher KYNA/3-HK compared to ACTH controls (p = 0.0393) and animals treated with ACTH + ketamine (p = 0.0102). No significant differences were observed between saline treated animals for tryptophan metabolites, however, saline + LPS + ketamine treated animals had significantly higher levels of pre-limbic AMPK and GSK3α/GSK3β compared to saline controls (p < 0.05). A significant positive correlation between FST immobilization time and serum CRP concentration was observed in all treatment groups.

Conclusions:Ketamine directly attenuated LPS-induced increases in tryptophan metabolite levels in the PFC of ACTH-treated animals, which may contribute to the antidepressant-like behavioral response in the context of this model. Neither LPS nor ketamine had a significant effect on prefrontal levels of tryptophan metabolites in saline-treated control animals. CRP levels in all groups were associated with immobility time in the FST, further supporting the role of inflammation in moderating stress coping. Targeted research in clinical populations is needed to determine the usefulness of inflammatory markers in stratifying precision medicine treatments. Ketamine's mechanism of action may optimally promote the antidepressant response in people with elevated inflammatory markers on TRD.

Key words:Treatment-resistant depression, ketamine, insulin, mTOR, immune system

Disclosure:Nothing to disclose.

Larry Zweifel*, Jordan Elum, Barbara Juarez, Grigory Loginov, Scott Ng-Evans, Sam Golden

University of Washington, Seattle, Washington, USA

Background:The dopaminergic neurons of the ventral tegmental area (VTA) are genetically and functionally distinct. How circuit connectivity and gene expression patterns in these populations confer their unique functionality is unclear. We seek to elucidate how genes and circuits intersect at the level of subpopulations of mesolimbic dopaminergic neurons to gain a more detailed understanding of the specialized roles of this system in motivated behavior, reinforcement learning, and decision making.

Methods:Fiber photometry has been used to measure calcium dynamics in genetically diverse dopamine populations during signaling-induced recovery, probabilistic reinforcement, and reward titration. Electrophysiology was performed to measure the synaptic connectivity and intrinsic properties of these cells. Single core RNA sequence analysis was used to identify differences in the gene network. Specific cell rage tracing, light sheet microscopy and whole brain connectivity analysis were used for 3D reconstruction of circuit connections.

Results:We found that dopamine subpopulations projecting to the nucleus accumbens nucleus or the nucleus accumbens shell exhibit differential calcium dynamics during cue-induced resetting, probabilistic reinforcement, and reward evaluation. Whole-brain connectivity analysis revealed distinct inputs for these cells, which were confirmed by in vivo optical stimulation of these inputs and subpopulation imaging. Electrophysiology revealed that these subpopulations have different inhibitory connectivity and intrinsic excitability. Consistent with these findings, disinhibition networks evoke dissociative response profiles in these cells. Finally, our gene expression analysis shows that the differential expression of ion channels within these cells contributes to their excitability and stimulus-response profiles.

Conclusions:Combining circuits, genes, systems, and behavioral analyses, we found that marked and graded differences in circuit connectivity, gene expression, and intrinsic excitability of VTA dopamine subpopulations converge to create unique functionality within these cell types of the brain's mesolimbic system.

Key words:Dopamine, behavior, neural circuits, molecular genetics, in vivo imaging

Disclosure:Nothing to disclose.

Justin Moscarello*, Diana Guerra, Wei Wang, Karienn Souza

Texas A und M University, College Station, Texas, EUA

Background:Although avoidance behavior is a common symptom of many anxiety disorders, the underlying neural circuitry remains a mystery. Here we report a series of experiments using a signaled active avoidance (SAA) procedure to model avoidance behavior in male rats. In SAA, the subject quickly acquires an association between a conditioned stimulus (CS) and an unconditioned aversive stimulus (US). As training progresses, the subject learns to perform a response (bidirectional walking) during CS to avoid US application. Over the course of SAA training, US presentation dramatically decreases, transforming from a specific threat during initial Acquisition to a surrounding distal threat when the avoidance response reaches asymptotic expression levels. Previous research indicates that the bed nucleus of the stria terminalis (BNST) mediates defensive responses to potential distal conditioned threats, suggesting a potential role for this region in the expression of active avoidance behavior. However, his role in SAA has yet to be explored.

Methods:We used a uniquely engineered drug-activated virus-mediated receptors (DREADD) approach to study the role of BNST in SAA. Rats received stereotaxic infusions of a solution containing one of the following AAVs, depending on the experiment: AAV5-hSyn-hM4D(Gi)-mCherry, AAV5-hSyn-hM3Dq-mCherry, or AAV5-hSyn-EGFP. After recovery, subjects received SAA training in which a CS tone (15 s, 70 dB) was preceded by an electric foot shock (0.7 mA, 0.5 s). Training was carried out in a rectangular chamber separated into two compartments by a partition with an open opening that allowed free movement between compartments. If the subject moved across the chamber to the other side during the CS, the CS ended and the EE was omitted. Upon completion of training, all subjects received test sessions preceded by the administration of 3 mg/kg of the DREADD agonist clozapine N-oxide (CNO) or vehicle (10% DMSO).

Results:We first tested the hypothesis that BNST is required for expression of the bidirectional active avoidance response. Male mice received intra-BNST infusions of AAV containing the gene construct for the hM4Di DREADD or GFP inhibitor. After recovery, the animals received four days of SAA training to achieve a stable level of avoidance. This was followed by two more days of SAA training preceded by offset IP injections of DREADD-CNO binder or vehicle. We found that CNO decreased avoidance responses and increased avoidance latencies in hM4Di subjects but not in GFP controls, demonstrating that BNST is required for bidirectional avoidance response expression. As some subjects in this experiment showed hM4Di expression in the medial septum (SM), we proceeded with an anatomical control experiment specifically targeting this region. We found no evidence of a role for MS, suggesting that the effects seen in our first experiment were specific for BNST. We then compared DREADD activation (hM3Dq) and BNST inhibition (hM4Di) in an avoidance test under extinction conditions (10 CS, no US) in which all groups received a common set of stimuli. After the AAV infusions and recovery, subjects received six days of avoidance training. 24 hours later, all subjects were evaluated after CNO or vehicle administration. This experiment confirmed that CNO reduced the expression of the avoidance response in subjects expressing hM4Di. Indeed, the CNO caused the hM4Di group to avoid at very similar levels to the low-avoidance group, which consisted of subjects who never successfully expressed the response during exercise, illustrating the level of behavioral reduction, which was caused by the inactivation of the BNST. In contrast, CNO administration to individuals expressing hM3Dq elicited a period of enhanced transmission that extended beyond CS presentation, whereas other groups rapidly returned to baseline levels of transmission after CS clearing. Analysis of other ongoing behaviors in the test indicated that these effects on bidirectional transport in the hM4Di and hM3Dq groups cannot be attributed to changes in freezing or general locomotor activity.

Conclusions:We conclude that the BNST is not only necessary for a normal level of avoidance, but also sufficient to potentiate the response outcome, establishing a region that has been identified as a crucial substrate for distal threat processing as a key mediator of avoidance behavior. This contrasts with prominent conceptual models of the behavioral processes underlying SAA, such as B. two-factor theory, which identifies putative anxiety states most closely related to processing an imminent threat as the primary trigger for the avoidance response. Our results support an updated multifactorial model in which post-encounter responses to a given threat are replaced by pre-encounter responses to a potential threat as the SAA learning curve progresses.

Key words:Fear, anxiety, avoidance, stria terminalis bed core, predatory immediacy

Disclosure:Nothing to disclose.

Alessia Mastrodonato*, Noelle Kee, Marcos Lanio, Michelle Jin, Andrea Munoz Zamora, Christine Ann Denny

Columbia University, New York State Psychiatric Institute, New York, New York, United States

Background:Stress is one of the biggest risk factors for anxiety and anxiety disorders such as major depression and post-traumatic stress disorder (PTSD). Previously, we showed that a single pre-stress injection of (R,S)-ketamine reduces behavioral distress and attenuates learned anxiety by modulating ventral hippocampus CA3 activity in male mice. We have recently discovered that a metabolite of (R,S)-ketamine ((2 S,6 S)-hydroxynorketamine (HNK)) also dampens learned anxiety. However, all of the brain regions that mediate the effects of (R,S)-ketamine and (2 S,6 S)-HNK on anxiety behavior are largely unknown.

Methods:Here we use a 3-shock paradigm of contextual fear conditioning (CFC) as a stressor 1 week after a single saline injection or (R,S)-ketamine (30 mg/kg) or (2S,6S).)-HNK ( ) 0.075 mg/kg) in adult male mice (8 weeks old, n=10 per group) 129S6/SvEv. Five days later, mice were re-exposed to the aversive context and sacrificed one hour later to quantify neural activity (ie c-fos expression) throughout the brain using an assay developed in our laboratory.

We then converted c-fos cell counts separated by brain region into correlation matrices and constructed whole brain networks to gain insights into functional connectivity.

Results:Administration of (R,S)-ketamine and (2 S,6 S)-HNK attenuates learned fear compared to saline mice (p<0.01 for both drugs). (R,S)-ketamine increases anxiety-related neural activity and connectivity in multiple brain regions (eg, ventral CA3, retrosplenial cortex, and temporal association area (p<0.01)), whereas (2S,6S )-HNK specifically increases connectivity within and between the prefrontal cortex and amygdala regions (p < 0.05).

Conclusions:Our results demonstrate that (R,S)-ketamine and (2,S,6,S)-HNK attenuate learned fear by differentially altering the correlated network activity. We find new nodes in the network that are altered by fear behaviors, allowing us to attack with pharmacological manipulations to alleviate fear. This work contributes to the understanding of prophylactic drugs as therapeutic tools in anxiety-related disorders.

Exclusive data: all data is new and unpublished

Key words:(R,S)-ketamine, (2S,6S)-HNK, fear conditioning

Disclosure:Nothing to disclose.

Robert Fetcho*, Puja Parekh, Margaux Kenwood, Laura Chalencon, David Estrin, Jolin Chou, Megan Johnson, Conor Liston

Weill Cornell Medical College, New York, New York, USA

Background:Effort assessment, a process of selecting actions based on the expected value of rewarding outcomes and expectations about the amount of work required to achieve them, plays a critical role in decision making. Assessment of exertion is disrupted in chronic stressful states and is partially aided by the anterior cingulate cortex (ACC), but the circuit-level mechanisms by which the ACC represents exertion-related signals and regulates effort-based decision-making decisions and reward seeking are not well defined.

Methods:We have developed an automated physiology-compatible platform for high-throughput assessments of exercise assessment in free-moving mice. In an elevated T-maze apparatus, animals (male C57BL/6 mice, 8-12 weeks old) were presented with a choice between water rewards of different magnitudes associated with different effort requirements. We used fiber photometry and optogenetics to record and manipulate the ACC neurons that project to the nucleus accumbens (ACC-NAc) while the mice performed this effort-based decision-making task. After training, a subset of mice was exposed to chronic exposure to corticosterone, a model of the neuroendocrine response to stress, and post-exposure, the behavioral paradigm was reassessed along with ACC-NAc recordings.

Results:We found that ACC-NAc activity anticipates and responds to reward acquisition; However, the circuit does not seem to encode the reward size. Instead, the magnitude of reward-related activity of the ACC-NAc scales with the amount of effort required to obtain the reward (N = 16 mice, 4384 behavioral tests, 3 experiments; linear mixed-effects model: interaction between type of reward and effort – F(2.4378) = 135.38 p < 0.0001). Next, we found that optogenetic silencing of this effort-sensitive reward signal resulted in a significant reduction in future effort-related decisions in a behavioral session (repeated two-way ANOVA measures: N = 18 mice (11 controls, 7 experiments), 2 experiments showed significant interaction) F(1.16) = 13.06, p = 0.0023 Post-hoc test Bonferonni control: baseline vs. stimulus p = 0.7, experimental: baseline vs. stimulus p = 0.0001). Finally, chronic corticosterone treatment resulted in significant impairments in effortless reward-seeking behavior, which correlated strongly with impaired ACC-NAc circuitry function (N = 5 mice, 10 sessions of 2 experiments. Linear T-effects model mixed (10) = 4.56, p = 0.002, R2 = 0.72).

Conclusions:Our results show that ACC neurons support load evaluation behavior through NAc projections. In particular, ACC-NAc circuit activity integrates information related to reward and effort, and this activity is critical for reinforcing future effort decisions. Chronic corticosterone leads to disruptions in this effort-sensitive reinforcement signal, which correlates with impaired reward-seeking behavior, suggesting a possible mechanism underlying stress-induced motivational deficits.

Key words:Anterior cingulate cortex (ACC), effort, reward, stress

Disclosure:Nothing to disclose.

Eshaan Iyer*, Jessie Muir, Serena Wu, Karen Wassef, Rosemary Bagot

McGill University, Montreal, Canada

Background:Impaired reward learning is associated with depression and other psychiatric disorders. The nucleus accumbens (NAc) is a key region involved in motivation and reward and is altered in depression. Susceptibility to depression-related behaviors is mediated by afferent glutamatergic projections from the ventral hippocampus (vHip) and medial prefrontal cortex (mPFC) to the NAc. The role of these glutamatergic inputs to the NAc in supporting reward learning remains relatively unexplored.

Methods:Here, we simultaneously recorded population-level mPFC activity and NAc vHip projections in adult male (n = 12) and female (n = 12) mice in a two-part bandit task using in vivo fiber photometry.

Results:Both neural projections dynamically encode information about the results of a given experiment. Rewarded versus unrewarded outcomes are associated with greater mPFC-NAc suppression right after an election (p < 0.001) and throughout the intertrial interval (ITI) (p < 0.01). In vHip-NAc, reward-associated suppression occurred with a longer delay after election (p < 0.01) and continued during the ITI (p < 0.0001). In both pathways, this reward-associated suppression persisted in subsequent studies (mPFC: p<0.0001; vHip: p<0.001), which showed neural representations of outcome modulated by reward history. We observed striking pathway-specific differences in mPFC-NAc projections that track historical outcomes, whereas vHIP-NAc projections preferentially encode unrewarded outcomes and track historical loss but no reward.

Conclusions:Taken together, these results indicate that the mPFC-NAc and vHip-NAc projections integrate results over time in a task-dependent manner to support reward learning. Given previous evidence identifying altered neural activity in these pathways in stress-induced states, these neural circuits may be relevant to understanding changes in reward learning in depression and other stress-related disorders.

Key words:Probabilistic reward learning, glutamatergic, nucleus accumbens glutamatergic afferents, mPFC, ventral hippocampus

Disclosure:Nothing to disclose.

Sean Piantadosi*, Veronica Porubsky, Madison Martin, Avi Matarasso, Tammy Nguyen, Michael Bruchas

University of Washington, Seattle, Washington, USA

Background:Acute stress and threat produce physiological anxiety, which is believed to facilitate planning and allow an organism to adjust its behavior for future environmental explorations. This serves as an adaptive mechanism, allowing fear and avoidance behaviors to be adapted and selected. However, in many mental disorders, this homeostatic behavioral response becomes maladaptive and dysfunctional, leading to excessive anxiety in situations where it is unwarranted or undesirable. Anxiety disorders characterized by this maladaptive response are the most common mental illness in the United States, affecting approximately 20% of the adult population. Clinically, we know that neuromodulators such as norepinephrine (NE) play a crucial role in long-term outcomes after exposure to stress. Despite this, the mechanism by which these monoamine neuromodulatory signals regulate the activity of the circuit associated with anxiety-like behavior remains poorly understood. An important modulatory system well positioned to mediate these behaviors is the noradrenergic system of the locus coeruleus (LC-NE), as it is one of the first to appear after stressful events and stimuli and activation of the LC and its projections into the basolateral amygdala is involved. (BLA) is anxiogenic. However, we know very little about how this critical LC-BLA neuromodulatory circuit generates fear-like behavior at the network, circuit, cell-type, transmitter, and receiver levels.

Methods:We performed two-photon calcium imaging of individual LC-NE neurons with an endoscopic prism lens while mice (n = 5, 3 males, 2 females) were exposed to the strong predatory stressor 2MT. We then modeled the effect of stress on LC activity and measured NE release in the BLA with an NE sensor (GRABNE2m) while using matched LC terminals in the BLA at a tonic frequency (5 Hz). Optogenetics and fiber photometry (n=6) activated, 6 male). We then performed free-motion calcium microendoscopic imaging of BLA neurons in classic assays for anxiety-like behavior while optogenously manipulating LC terminals at stress-induced tonic frequency (Dbh-Cre mice; n = 8, 5 males, 3 females) . Pharmacological manipulations (using selective α1 and β2 antagonists) were used to identify which adrenergic receptors mediate the anxiogenic effect of LC-BLA stimulation. Support vector classifiers were trained to predict whether mice were in an anxiogenic context based only on activity in the BLA population. Graphical theoretical analyzes were developed to test whether activation of the tonic LC pin would cause correlated increases in firing of BLA neurons, as would be expected from a gain control signal. Finally, the CRISPR-SaCas9 deletion of the gene encoding adrenergic receptor (AR) subtypes (α1 and β2-AR) within the BLA was combined with microendoscopic calcium imaging to assess the need for these receptors for behavioral expression, similar to post-anxiety anxiety. stress. and how each of these receptor subtypes on specific cell types contributes to encoding state anxiety in the BLA population.

Results:It was found that the activity of LC-NE neurons is highly synchronous when mice consume an appetizing stimulus. When mice were exposed to the predator odor stressor 2MT, exploratory licking behavior was dramatically reduced (t(3)=2.82, p<0.05). This reduction in exploratory licking coincided with an increase in tonic firing rate in a large subset of LC-NE neurons (t(37) = 18.1, p < 0.0001), suggesting that in many LC-NE neurons - activation stress-induced tonicity, although the responses became less synchronous as a population. We then modeled the effect of this increased tonic activation on NE release within the BLA and found that 5 Hz activation of LC-BLA terminal activation produced sustained increases in NE release as measured by the GRABNE2m signal (p < 0.001). This effect was blocked by the α2-AR antagonist yohimbine. Using combined optogenetics and free-motion microendoscopy, we recorded the activity of individual BLA neurons while manipulating LC-BLA terminals at a tonic frequency and assessed anxiety-like behaviors. We found that tonic LC-BLA activation was anxiogenic (RM-ANOVA, p<0.05; post-hoc t(7)=3.41, p<0.05), a change in BLA activity promoted neurons that were activated when the mice entered the anxiogenic context (open-field center and elevated null maze with open arms) and improved the ability of the BLA population activity to classify the mouse position within the arenas (t(6) = 2.95, p < 0.05). These effects were blocked by the β2-AR antagonist propranolol (p > 0.05). Tonic activation of LC-BLA resulted in persistent changes in the correlating structure of BLA neurons that persisted after cessation of stimulation, suggesting that mimicking stress through specific activation of LC inputs to BLA produces persistent changes in BLA network activity . CRISPR-SaCas9 deletion of Adrb2 (gene encoding β2-AR) in Vglut1 neurons in BLA was efficient, resulting in approximately 40% deletion.

Conclusions:It has long been suspected that neuromodulation, and in particular the neuromodulator norepinephrine, serves as a gain control signal capable of altering the activity of large populations of downstream neurons. Here, using a combination of behavioral, visual, and molecular approaches, we show that sustained release of norepinephrine following stress or optogenetic activation leads to long-lasting changes in BLA network activity, consistent with this theory, and identify the receptor potential (β2-AR) that may be required for this type of network change.

Key words:Locus coeruleus (LC), norepinephrine, in vivo calcium imaging, basolateral amygdala, stress and anxiety behaviors

Disclosure:Nothing to disclose.

Lauren Malave*, Rushell Dixon, John Bickel, Christoph Anacker

Columbia University and New York State Psychiatric Institute, New York, New York, United States

Background:A history of early life adversity (ALS), such as Trauma, such as physical or emotional, experienced during sensitive periods in early development increases the risk of psychiatric disorders later in life and reduces response to antidepressant treatment. ALS exerts permanent changes in the developmental pathway of neural circuits and neurotransmitter systems, such as: B. the serotonergic system, in ways that may differ from the effects of stress or genetic predisposition in adults. We have previously found that hyperactivity in the ventral dentate gyrus (vDG) region of the hippocampus increases stress responses. Here we examine the interaction between ALS, serotonin (5-HT) and DG function in the overgeneralization of anxiety, a form of cognitive distortion characteristic of a variety of mental disorders. Understanding the neurobiological mechanisms underlying ALS's specific contributions to anxiety overgeneralization may help us to design better treatments or preventions for psychiatric disorders.

Methods:To induce ALS in mice, we used the limited condition and nesting (LBN) model of postnatal days (P) 3-10. LBN causes fragmented and unpredictable maternal care, as well as rough handling and kicking in the pups. To investigate whether the effects of ALS can be rescued by enhancing 5-HT signaling, we used a transgenic mouse model to express 5-HT1A autoreceptors in raphe 5-HT neurons (Pet1-tTS; Htr1atetO/tetO -mice) to inactivate conditionally increase 5-HT signaling from birth. Control and LBN-exposed offspring with and without 5-HT1A knockdown were tested on an anxiety discrimination task during adolescence (P35) and adulthood (P56). Mice received a foot shock on day 1 in context A and were again challenged in context A on day 2. Two hours after re-exposure to context associated with shock A, mice were placed in a new safe context B. freezing was recorded using FreezeFrame software (Actimetrics) to compare fear expression between context A and context B on day 2 and vDG granule neurons after exposure to context B. Tissue 5-HT levels in control vDG and ALS-challenged mice were measured using HPLC.

Results:Female, but not male, mice exposed to LBN overgeneralize between an A context associated with foot shock and an adult safe context B at P56, indicated by a lower discrimination rate between the two contexts (WT control): 0.63 ± 0.04 n = 26 , WT-ELA: 0.34 ± 0.1 n = 14, 2-way ANOVA ALS vs. genotypic interaction F(1.55)= 7.7, p = 0.01, Tukey post hoc, WT control vs. ELA p = 0.01). Elevated 5-HT levels rescued behavioral deficits observed in adulthood (WT-ELA: 0.34 ± 0.1 n=14; ELA 5-HT1A knockdown: 0.66 ± 0.06 n=11; ELA ANOVA of 2nd way versus genotypic interaction F(1.55) = 7.7 p = 0.01; Tukey post hoc, p = 0.02). These differences were only seen at P56 and not at P35 for all groups, suggesting that LBN leads to cognitive deficits later in life. At P56 in females, we found increased expression of Fos in vDG of mice exposed to ALS after exposure to safe context B compared to controls (control WT: 67.4 ± 4.1 n = 3; ALS WT: 42.5 ± 5.6 n = 6, 2-way ELA ANOVA effect F(1.11) = 8.5, p=0.01, Tukey post hoc, control vs. ELA p=0.02). This increase in Fos expression was found only in the vDG, an area involved in anxiety-related behavior, and not in the dorsal GD, an area involved in spatial navigation. This increase in vDG-Fos expression was rescued by the 5-HT1A knockdown, similar to the effect of 5-HT1A on overgeneralization of rescued fear. The proportion of Fos+ 5-HT neurons in the median raphe nucleus (MnR), the nucleus that projects to the hippocampus, was reduced in ALS-experienced mice (control: 16.4 ± 1.02 n = 5, ALS: 8 .9 ± 1.3, n= 5, 2way RM ANOVA ALS vs. interaction region F(1.8)=28.2, p= 0.001; Sidak post hoc, control vs. ALS, p = 0.0004 ). No effects of ALS were observed on the dorsal raphe nucleus or the total number of 5-HT neurons, suggesting that ALS causes dysfunction in MnR 5-HT neurons, regardless of the total number of neurons. Furthermore, we found that vDG 5-HT levels were reduced in animals exposed to ALS at P56 (control: 232.1 ± 35.6 n=6; ALS: 112.2 ± 13.9 n=6; t-test unpaired, p=0.01), but not at P35, suggesting impaired 5-HT modulation of vDG manifesting in adulthood.

Conclusions:Our results demonstrate that ALS causes vDG hyperactivity and fear of overgeneralization in adult female mice, and that increasing 5-HT levels from birth can reverse these neurobiological and behavioral deficits. Understanding how vDG 5-HT regulation mediates ALS-induced behavioral deficits may offer new potential treatment options for psychiatric disorders with early life onset.

Key words:Early life adversity, serotonin, dentate gyrus, early life stress, neural circuitry

Disclosure:Nothing to disclose.

Juliana Corlier*, Andrew Wilson, Cole Citrenbaum and Andrew Leuchter

University of California – Los Angeles, Los Angeles, California, United States

Background:Transcranial Magnetic Stimulation (TMS) is an effective treatment for various psychiatric and neurological disorders such as depression, chronic pain, obsessive-compulsive disorder, smoking cessation and others. Although therapeutic efficacy is thought to result from effects on generalized networks beyond the stimulation site, the role of stimulation frequency is unclear. Several frequencies have been used successfully for therapeutic purposes in the past, including 1, 5, 10, 18, 20 Hz and theta burst stimulation. It remains to be clarified how the triggered activation patterns change frequently. Furthermore, it is unclear whether circuits in the brain have resonant frequencies (RF) to which networks preferentially respond, and whether these frequencies differ from person to person.

Our hypothesis is that the different frequencies would produce spatially different patterns of electroencephalographic (EEG) activity that would reflect how different brain circuits respond to stimulation. We also hypothesized that preferred FRs differ from person to person. We use a recently developed TMS-EEG retrieval paradigm to assess TMS-evoked spectral changes and oscillatory entrainment in the source-localized EEG signal and RF identification between subjects.

Methods:80 subjects with major depressive disorder (MDD) underwent TMS interrogation at 71 frequencies ranging from 3 to 17 Hz (in 0.2 Hz increments) delivered to the left dorsolateral prefrontal cortex (DLPFC). Each stimulation rate consisted of 40 pulses with an interval of 26 seconds between rates. Frequency order was randomized for all subjects.

The 64-lead EEG was recorded at baseline, throughout the interview process and after the session. We use a specially designed artifact removal pipeline to remove TMS pulse artifacts, decay artifacts, and traditional EEG artifacts (electrical noise, eye, muscle, and cardiac artifacts) after every TMS pull. The period [-1000 0 ms] before stimulation and [0-1000 ms] after each frequency was extracted and used for brainstorm source location. We created a head model with the Boundary Element Method (BEM) using digitized electrode positions and the OpenMEEG toolbox. The source time series were reconstructed using the minimum norm estimation (MNE) method to obtain the inverse solution, which addresses the erroneous nature of the EEG source estimation through regularization. For each frequency, we obtained an average cortical source activation map for each frequency band. Compared to the baseline activity, only circuit activation greater than z > =2.5 scores is shown.

Results:We present activation maps located at the middle source (Figure 1) as well as individual subject examples (Figure 2) for the 71 stimulation frequencies at both wideband and delta filtered frequencies [1–4 Hz]. , theta [4–8 Hz], alpha [8-12 Hz], beta [12-20 Hz], and low range [20-30 Hz]. Varying frequencies of TMS stimulation elicit widespread cortical activations well beyond the site of stimulation. The spatial distribution of elicited patterns varies significantly between individuals, depending on the frequency of stimulation.

Conclusions:We show that different frequencies of TMS stimulation evoke very different spatial activation patterns in the EEG signal located at the source and that these activation maps vary as a function of frequency and between individuals. These results have clinical implications that suggest that personalized treatment frequency should be used to improve target brain circuit training.

Key words:Brain stimulation, TMS-EEG, frequency optimization

Disclosure:Nothing to disclose.

Ronald Kim*, Mala Ananth, Niraj Desai, Lorna Role, David Talmage

National Institutes of Health, Bethesda, Maryland, USA

Background:Basal forebrain cholinergic neurons (BFCNs) play critical roles in a variety of behaviors. In addition to the well-established role of BFCNs in learning and memory, recent evidence indicates that BFCNs encode innate behavior. For example, we show that mice approach an appetizing odor (2-phenylethanol) and avoid an unpleasant odor (predator urine). These innate behaviors are associated with an increase in the number of activated cholinergic neurons in the ventral pallidus (VP). The aim of the present studies is to extend these findings and further investigate the functional importance of VP cholinergic neurons.

Methods:To better understand how VP cholinergic neurons respond to an appetizing versus aversive odor, fiber photometry was used to characterize calcium activity in vivo. Chat-Cre mice were injected with AAV-syn-Flex-GCaMP6F and received a fiber optic implant targeting the PV. After habituation, the calcium activity of VP cholinergic neurons was assessed in response to appetizing or aversive odor on one day and opposite odor on the next day. To test whether the same or different subsets of VP cholinergic neurons are activated in response to each odor, Chat-cre x cFos-tTA/GFP mice were injected with a VP-cre activity-dependent viral vector (ADCD-hM4Di). This strategy uses a tet-off system, in which activated cholinergic neurons are permanently stained with mCherry in the absence of a doxycycline (DOX) diet. cFos-GFP can be used to tag neurons that were activated in a different context. Mice underwent behavioral testing for 3 days, Day 0 = habituation (DOX-on), Day 1 = exposure to odor 1 or saline (DOX off, activated VP cholinergic neurons labeled with mCherry), Day 2 = exposure to odor 2 or saline solution (DOX-on, immunohistochemistry for GFP and Chat). To investigate the role of VP cholinergic neurons in innate behavioral responses to odor exposure, syn-DIO-hM4Di was injected into chat cre mice. Fifteen minutes after IP injection of a subthreshold dose of clozapine, preference for appetizing or aversive odor was assessed in a Y-maze. For selective chemogenetic inhibition of previously activated cholinergic VPN neurons, mice were injected with ADCD-hM4di Chat-cre x cFostTa/GFP. After habituation, mice were withdrawn from a DOX diet and challenged with the appetizing or aversive odor (mCherry-labelled activated VP cholinergic neurons). Twenty-four hours later, mice were injected with clozapine to inhibit previously activated VP cholinergic neurons and the preference for the same odor was assessed in a Y-maze.

Results:Preliminary results from fiber photometry indicate that VP cholinergic neurons exhibit reliable, time-synchronized increases in calcium activity in response to appetizing and aversive odors. We also examined whether the cholinergic neurons activated in the PV were the same or different neurons after exposure to appetizing versus aversive odor. When mice were challenged with the same odor on days 1 and 2, they showed a significant increase in colocalization of mCherry (VP cholinergic neurons activated on day 1) and GFP (VP cholinergic neurons activated on day 2). This indicates the reactivation of previously activated VP cholinergic neurons when exposed to the same odor. However, when mice were challenged with a distinct odor on day 2, no co-localization of mCherry and GFP was observed. These results are consistent with the existence of two distinct subpopulations of VP cholinergic neurons: one population that is activated in response to an appetizing odor and a second distinct population that is activated when exposed to an aversive odor. Our chemogenetic inhibition experiments with syn-DIO-hM4Di showed that general inhibition of all subpopulations of VP cholinergic neurons abolished the normal onset of appetizing odor. The mice spent more time in the arm paired with saline, meaning the appetizing smell was now repulsive. In contrast to VP cholinergic blocking of approach behavior, avoidance of aversive odor was observed. Similar results were observed when specifically targeting previously activated VP cholinergic neurons. Selective inhibition of previously activated VP cholinergic neurons in response to the approach behavior eliminated the appetizing odor and resulted in the avoidance of the appetizing odor during the preference test. Targeted inhibition of previously activated VP cholinergic neurons after exposure to the aversive odor resulted in normal avoidance of the aversive odor.

Conclusions:The results of the present studies demonstrate (1) increases in in vivo calcium activity of VP cholinergic neurons in response to appetizing and aversive odor; (2) the PV contains two distinct and non-overlapping subpopulations of cholinergic neurons that are activated exclusively by appetizing or aversive stimuli; and (3) chemogenetic inhibition (general inhibition or selective inhibition of previously activated neurons) of VP cholinergic neurons alters innate behavioral responses to appetizing but not aversive odor. In ongoing studies, we are investigating how these subpopulations of VP cholinergic neurons differ, with a focus on mapping their projections and measuring their fundamental electrical properties.

Key words:Acetylcholine, Ventral Pallidum, Valencia

Disclosure:Nothing to disclose.

Christopher Guevara*, Kumayl Alloo, Romario Thomas, Alexander Tielemans, Kyomi Blake, Jamal Magoti, Swati Gupta, Alexandra Magee, Deanna Benson, George Huntley

Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, Nova York, Nova York, EUA

Background:Parkinson's disease (PD) is associated with early-onset non-motor psychiatric symptoms such as depression and anxiety, appears independent of dopaminergic neuron loss, and is poorly understood. The G2019S mutation in the Lrrk2 gene is one of the most commonly associated PD risk gene mutations found in late-onset sporadic and familial PD. Stress increases the risk of Parkinson's and depression, and previous laboratory work has shown that young adult Lrrk2-G2019S knockin mice exhibit synaptic and non-synaptic plasticity adaptations to social stress that differ significantly from wild-type knockin mice.

Methods:To determine whether the effects of social stress generalize to other forms and magnitudes of behavioral stress, we subjected young adult wild-type (WT) and G2019S knock-in (GS) mice to a standard daily variable stress (SV) paradigm. consisting of a 1 hour stressor per day for three days in the following order: 100 light stomps, tail tucks and holds. This stress paradigm was applied for 6 days (6d-VS) or 28 days (28d-VS). After the final stressor, unstressed control cages and stressed mice were subjected to a battery of tests (free field test, social interaction test, and suppressed novelty feeding) to examine stress-induced behavioral changes.

Results:In WT mice, we found no major changes in behavioral studies after 6d-VS, but significant stress effects occurred in post-stress behavioral studies at 28d-VS, as expected from previous work. In contrast, GS mice showed significant stress susceptibility as early as 6d-VS, which persisted after 28d-VS. These behavioral adaptations are specifically driven by stressful experiences, as no differences were observed between genotypes under stress-free control conditions.

Conclusions:These data demonstrate that the G2019S mutation lowers the overall stress susceptibility threshold across all stress paradigms and elicits an evolutionary set of neuronal and behavioral adaptations distinct from WT over time. These different susceptibilities may influence the onset of psychiatric symptoms in human Parkinson's patients. Future studies will investigate how different brain regions are affected by different durations of stress at the cellular and synaptic level. Understanding these interactions will provide insight into the neural adaptations of individuals with the G2019S mutation and provide new targets for improving mood-related symptoms associated with Parkinson's.

Key words:Acute and chronic stress, synapses, glutamate, Parkinson's disease, depression

Disclosure:Nothing to disclose.

Julia Castello Saval*, Victor Luna, Hannah Chung, Rene Hen

Columbia University, New York State Psychiatric Institute, New York, New York, United States

Background:Major depression is the leading cause of disability worldwide, and approximately one third of patients do not respond to pharmacotherapy. For treatment-resistant depression, electroconvulsive therapy (ECT) is an effective alternative with a rapid onset of action. ECT is known to increase neurogenesis in the dentate gyrus (DG) of the hippocampus, a region of the brain that is highly susceptible to stress and which plays an important role in the development of depression. In this study, we examined the contribution of adult granule cells (abGC) to the mechanism of action of ECT.

Methods:Electroconvulsive stimulation was administered on alternate days for 10 sessions. Mice were anesthetized with isoflurane and electrical stimulation was administered through cut auricular electrodes (120 Hz, 0.5 mA, 1 s). Behavior was assessed one week after the last session in the forced swimming test and novelty suppression feeding test (men, n=9–10 per group). In the forced swimming test, mice were placed in a bowl of water (25°C) and swam freely. The immobility time was quantified with Videotrack. In the novelty suppressed feeding test, mice were deprived of food for 19 hours and placed in a bright new arena with a food pellet in the center, the latency to eat the food pellet was measured. For irradiation of the hippocampus after anesthesia, mice were placed in a stereotaxic frame and cranial irradiation was applied using a focal X-ray lead shield. A cumulative dose of 5 Gy was administered over 3 sessions. Results between groups were compared using one-way ANOVA for statistical group comparisons or multiple t-tests where appropriate.

For fluorescence imaging, animals (males, n = 5 per group) were perfused and brains were sectioned. The sections were submitted to washing steps, antigenic recovery with sodium citrate buffer and blocking step with 10% normal donkey serum. Sections were incubated overnight at 4°C in primary antibody (rabbit anti-doublecortin, 1:400, rabbit cFos, 1:400, Synaptic Systems). The next day, sections were washed and incubated in secondary antibody (Alexa Fluor 488 anti-rabbit). Sections for confocal images were prepared.

Slice electrophysiology was performed with a Nestin-CreERT2 line crossed with a channel rhodopsin line to drive channel rhodopsin expression in adult neurons. Tamoxifen was injected 6 weeks before whole cell current clamp recordings to induce Cre recombinase. Whole cell recordings (-70 mV) were obtained using a patch pipette (4.5-6.5 M). For abGC optogenetic stimulation, pulses of light were delivered through a 40x objective directly onto brain slices.

Results:Electroconvulsive stimulation, the mouse model of ECT, rescues the depression-like phenotype of mice administered chronic corticosterone (CORT) in the novel feeding suppression test and anxiety-related test. vehicle/fake 100.4 ± 48.61; Vehicle/ECS 113.5 ± 65.8 Unpaired Student's t test: p = 0.6325. CORT/Sham 272.3 ± 33.76; CORT/ECS 175.7 ± 41.58 unpaired Student's t-test: p = 0.0458). In the forced swimming test, a stress coping test, the ECS rescued the depressed phenotype in the vehicle group and in the CORT group. Vehicle/Wrong 124.0 ± 11.02; Vehicle/ECS 80.86 ± 27.92 One-way multiple comparisons ANOVA test: p = 0.006683. CORT/Sham 126 ± 17.41; CORT/ECS 87.46 ± 11.04 p = 0.005860.

X-ray ablation of abGC renders mice unresponsive to the new ECS forced swimming and suppressed feeding test. false/simulated 272.3 ± 33.76; simulated/ECS 164.1 ± 38.95 unpaired t-test: p = 0.0501; X-ray/simulation 309.1 ± 29.15; XRay/ECS 318.2 ± 28.24 ANOVA test with unidirectional multiple comparisons: p = 0.8283.

ECS stimulates the production of abGC, as evidenced by increased levels of doublecortin (DCX), a marker for young neurons. Furthermore, we visualized presynaptic buds using transgenic mice expressing synaptophysin YFP in DG. After ECS, the number of dots in the granule cell layer increases, indicating a greater presynaptic terminal density. In contrast, when abGCs are knocked out, the ECS-induced increase in synaptic buds is comparable to that of animals treated with Sham Sham 0.922 ± 0.03984; ECS 1.240 ± 0.03745 X-rays 0.3468 ± 0.03327 One-way ANOVA multiple comparison test p<0.001.

Intrigued by this finding, we used a Nestin-CreERT2 mouse strain crossed with a canalhodopsin-2(ChR2)-EYFP flocked mouse strain to express ChR2 in abGC. This allowed recordings of whole cell clips in mGC after abGC optogenetic stimulation. By comparing mice receiving 10 sessions of ECS with sham animals, we found that abGC stimulation induced an inhibitory current in mGC, which increased after pharmacological suppression of the excitatory current component using the AMPA antagonist NQBX and the NMDA- antagonists shown. , AVP. Furthermore, the addition of the mGluR2/3 antagonist APICA abrogated the inhibitory current in the mGCs.

All results are presented as mean ± S.E.M.

Conclusions:To integrate these results, we propose that ECS induces abGC neurogenesis and axonal sprouting, leading to an increase in the number of abGC presynaptic knobs in the granule cell layer, which in turn results in increased activation of mGluR2 receptors in leads mGC. The resulting decrease in DG activity may be responsible for the antidepressant effects of ECS.

Key words:Electroconvulsive therapy, hippocampal neurogenesis in adults, major depression, dentate gyrus

Disclosure:Nothing to disclose.

Lucille Johnston, Amanda Amilcar, Rachel Ding, Alexander Harris*

Columbia University, New York State Psychiatric Institute, New York, New York, United States

Background:Anhedonia, defined as a reduced desire for pleasure, is one of the core symptoms of depression. Stress, a risk factor for depression, decreases reward seeking in both humans and mice. We have recently shown that ventral tegmental area (VTA) activity of the nucleus accumbens (NAc) is behind the reduction in anticipation observed after a single episode of restraint stress (Lowes et al., Nature Communications 2021). However, the exact nature of the behavioral changes (e.g., “want” versus “like”) that underlie reward-seeking deficits after chronic stress remains unknown. Furthermore, the impact of chronic stress on reward circuitry activity remains controversial, with studies reporting increases and decreases in rates of VTA dopamine activation (Tye et al. Nature 2013; Chaudhury et al. Nature 2013). In this study, we examined rates of VTA and NAc activation during reward seeking after chronic stress in mice.

Methods:We simultaneously implant chronic electrodes into VTA and NAc of male and female mice to record local field potential (LFP) and single unit activity (C57BL/6J 3 males, 4 females). We trained mice to associate a color with reward availability (CS + ) and another color with no condensed milk reward (CS-) with a criterion of 70% correct responses for CS +  on two consecutive days. We then recorded neuronal activity while the mice performed the task. Mice were then exposed to chronic social defeat stress (CSDS) for 10 days and 24 hours after the last day of defeat, they performed a social interaction task and a reward task. We analyzed the data with a custom MATLAB script and used Pearson's correlation to correlate the effects of stress on social interaction and reward seeking.

Results:We found that chronic stress led to a reduction in rates of anticipatory and post-consumption licking that lasted more than 24 hours and correlated with the SI ratio (N = 7, r = 0.79 for anticipation, r = 0.87 for consumption, p < 0.05). 🇧🇷 We also classified neurons into their putative identities (eg, dopaminergic VTAs, GABAergic VTAs, NAc-MSN, etc.) and analyzed the neural activity evoked by licking and the synchrony between regions to determine the associated neural activity for rewards. 🇧🇷

Conclusions:Taken together, these data suggest that chronic stress induces longer-lasting deficits in reward processing and allows analysis of the contribution of individual cell populations to anhedonia.

Key words:Reward, neural circuitry, chronic stress

Disclosure:Genetics: Advisory Board (own)

Nicole Crowley*

Penn State University, University Park, Pennsylvania, USA

Background:Somatostatin neurons (SST) in the prelimbic (PL) cortex mediate a variety of behavioral states, from alcohol use to fear learning and avoidance behaviors. However, little is known about the role of somatostatin peptide in signaling cortical function and behavior. Here we attempt to characterize the unique physiological and behavioral roles of the SST peptide in the PL cortex.

Methods:We used a combination of ex vivo electrophysiology, in vivo calcium monitoring, and in vivo peptide pharmacology to study the role of SST neurons and peptide signaling in the mouse PL cortex. Electrophysiology of whole cell sections in male and female C57BL/6J mice was performed on pyramidal and GABAergic neurons of the PL cortex to characterize the pharmacological mechanism of SST signaling. Fiber photometric recordings of GCaMP6f fluorescent calcium signals from SST neurons were performed to characterize the activity profile of SST neurons during elevated plus maze (EPM) and open field (OF) exploration. In addition, we used local administration of a SST broad receptor (SSTR) agonist in bilateral PL cortex to test the causal effects of SST signaling on the same exploratory behaviors.

Results:Activation of largely hyperpolarized SSTR layer 2/3 pyramidal neurons in the PL cortex in male and female mice ex vivo through mechanisms of action mediated by monosynaptic and polysynaptic GABA neurons. This included a reduction in the resting membrane potential of female (t13=2.205, p=0.0460) and male (t16=2.889, p=0.0107) pyramidal neurons, an effect that was greater in the presence of TTX in both women (t6= 5.095 , p = 0.0022) and men (t4 = 3.448, p = 0.0261). Many other measures of excitability were also significantly altered in both cases. Hyperpolarization was blocked by prior use of the SSTR antagonist cyclosomatostatin (Cyclo-SST) and was not reversible. SST neurons in PL were activated during EPM and OF scanning, indicating task-related recruitment of these neurons. Specifically, SST neurons were more active while the mice were in the open arms compared to the closed arms of the elevated plus maze (t10 = 6.101, p < 0.001) and were more active while the mice were in the center compared to the edges of the labyrinth. the open field (t10= 2.797, p= 0.0189). No gender differences were observed in the fiber photometry experiments. Finally, consistent with this scan-related activity profile, administration of SSTR agonists directly into the PL improved open-arm scanning in the elevated plus maze in male mice, with no effect in female mice (2-way ANOVA; Fsex(1 ,26 ) = 0.6452, p = 0.4291; Fdrug(1.26) = 3.462, p = 0.0741, Fsex x drug (1.26) = 7.868, p = 0.0094). We also saw a significant increase in the number of dead dips in the open arms of the elevated plus maze in male mice (2-way ANOVA; Fsex(1.26) = 5.917, p = 0.0222; Fdrug(1.26) = 3.264 , p=0.0824, Fsex x drug (1.26)=5.614, p=0.0255).

Conclusions:Here, we demonstrate a novel role for the SST peptide system within the PL cortex, demonstrating peptide-induced hypoexcitability of PL circuits and modulation of PL-dependent exploratory behavior.

Key words:Somatostatin, prelimbic cortex, cutting electrophysiology, fiber photometry

Disclosure:Nothing to disclose.

Kristen Ellard*, Walker Pederson, Samadrita R. Chowdhury, Tracy Barbour, Joan A. Camprodon

Harvard Medical School, Boston, Massachusetts, EUA

Background:Transcranial magnetic stimulation (TMS) of the dorsolateral prefrontal cortex (DLPFC) is an FDA-approved standard of care intervention for treatment-resistant depression. However, the mechanisms by which DLPFC-TMS is related to response to treatment are poorly understood. Investigating the mechanisms of TMS is crucial to improve treatment outcomes, which currently show high response but low remission rates (~30%). Deficits in emotion regulation (ER) have been repeatedly demonstrated in depression, which are related to symptom severity and response to treatment. Healthy ER involves sensing stress, initiating regulation, and cognitive control according to internal and external contextual demands, processes that require adaptive coordination between neurocircuitry comprising stress, frontoparietal control, and default mode functional networks. . Here, we examine the effects of a repetitive course of (r)TMS to the left DLPFC on resting-state functional connectivity in broader ER-supporting neurocircuitry that includes canonical functional networks.

Methods:Based on the existing literature (e.g. Kohn et al., 2014; McTeague et al., 2020), an analysis of the functional connectivity between individually derived DLPFC target ROIs and ER-related regions of interest (ROIs) was performed on data a priori Patients selected from 24 patients with depression (50% female, mean age 39.91 ± 3.04, 92% Caucasian) who received an intervention cycle (36 sessions, 120% MT, 10 Hz rTMS, 3000 pulses) of Left DLPFC-rTMS. Selected ROIs included regions within the limbic system (LIMB), dorsal attention (DA), frontoparietal control (FPC), and salivary/ventral attention network (SalVA) in default mode (DMN). Significant changes before and after TMS in target DLPFC: Functional connectivity of ER ROI was tracked using linear regressions to elucidate the relationship between changes in ER functional neurocircuitry and changes in clinically relevant measures of ER in responders (Resp; n =10) versus non-responders (No Resp; n = 14). To understand TMS-related changes within the broader ER-related neurocircuitry, ROIs that showed significant pre-post-TMS functional connectivity to the DLPFC target and a significant relationship to changes in ER-related clinical response were characterized. based on the functional connectivity of the whole brain.

Results:Significant changes were found before and after TMS in the functional connectivity between the DLPFC target and regions in the LIMB (l. amygdala, resp: t = -1.82, p = 0.05, non-resp ns; r. hippocampus, resp. : - 2.07 , p = 0.03, non-response ns), SalVA (r. anterior insula, resp: t = 2.11, p = 0.03, non-response ns; r. VLPFC, resp: t = 1.12, p = 0.10, non-resp: t = 2.08, p = 0.02) and precuneus/posterior cingulate DMN networks, resp: t = 2.12, p = 0, 03, non-resp ns). Changes in ER-target ROI functional connectivity were significantly associated with improvements in ER measures (amygdala DLPFC delta/negative affect delta, z=-1.96, p=0.05; hippocampus DLPFC delta/delta affective control, z= - 2.50, p = 0.02, delta DLPFC-anterior insula/delta negative affect, z = -2.45, p = 0.01, delta DLPFC-VLPFC/delta -affective control, z=2.89, p=004, delta DLPFC precuneus, PCC/delta affective control, z=2.15, p=0.03). Follow-up graphical analyzes identified significant pre-post TMS increases in intermediate centrality (a measure of a region's influence on information flow between regions and networks) in the right anterior insula/VLPFC (p = 0.03). Significant changes in functional connectivity between this node and broader ER neurocircuits were found after TMS (all p's < .05), with the strongest effect between VLPFC/anterior insula and DMN functional connectivity (precuneus/PCC). , t = -2.63, p = 0.007). A significant association was found between these changes in functional connectivity and measures of negative affect (t = 2.00, p = 0.05) and rumination (t = 2.01, p = 0.05).

Conclusions:TMS treatment applied to individualized DLPFC targets resulted in extensive changes in functional connectivity between the DLPFC target site and limbic network regions, prominent and standard in treatment-responsive patients. These changes were significantly associated with changes in clinically relevant ER measures. The right anterior insula/VLPFC showed a greater impact on the broader neurocircuitry of emotion regulation, as measured by betweenness centrality, and TMS-related changes in functional connectivity between this region and DMN regions were significantly associated with changes in negative affect and in rumination, two central features of emotional dysregulation. These results suggest that more precisely targeting neurocircuitry related to emotion regulation with TMS may be a way to increase overall response rates in treatment-resistant depression.

Key words:Repetitive transcranial magnetic stimulation (rTMS), emotion regulation, depression

Disclosure:Nothing to disclose.

Andrew Gerlach*, James Wilson, Casco Karim, Howard Aizenstein, Carmen Andreescu

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:Major depression accounts for more disability-adjusted life years than any other mental illness, yet the dominant treatment approach is essentially trial and error. The resulting delays in recovery increase personal, social and even economic costs. This problem is exacerbated in senile depression (LLD), in which the disorder has greater heterogeneity, longer response time, lower remission rates, and increased risk of relapse. Therefore, biomarkers of early treatment response in LLD to improve response time and outcome are an important strategic goal of neuroimaging research. However, the role of biological sex has not been sufficiently studied in the evaluation of magnetic resonance-based biomarkers.

Methods:In two LLD studies (NEMO [R01 MH076079-15]: n = 28, Circuits2 [R01 MH076079-09]), baseline and post antidepressant treatment demographic information, baseline depression severity, and IM fMRI scans were collected in the state rest (day 1): n = 51). Remission was defined as a final MADRS score of 10 or less for at least 2 weeks and is subject to blind clinical assessment. The Shen50 atlas was used to calculate functional region-to-region (FC) connectivity for 82 non-cerebellar regions (excluded due to poor coverage). Differential connectivity (DC) was calculated by subtracting baseline CF from CF on day 1. The role of biological sex was assessed in explanatory and predictive frameworks. For explanatory framework, gender differences between senders and non-senders were assessed using two-sample t-tests on DC for each pair of regions. For the predictive framework, a random forest classifier was used to predict each participant's remission status. The models were adjusted and tested separately with all participants, only women and only men. Monte Carlo cross-validation was used to assess the predictive power of CD and clinical covariates in predicting remission status across seven different model specifications for each study. The importance of the variables was assessed using the Gini importance measure scored by the trained random forest models. The average accuracy and area under the receiver performance curve metrics were used to evaluate the prediction performance of each model.

Results:The location and direction of CD differences between remitters and non-remitters, as well as the brain regions important for predicting remission, differ significantly by gender. Remission prediction was significantly improved by fitting separate models for men and women. Furthermore, males showed stronger CD group differences between remitting and non-remitting than females, with large differences in the bilateral caudate, bilateral temporal pole, and left postcentral gyrus. These regions were also important for prediction in all-male models. Women, on the other hand, showed weaker group differences in CO between senders and non-senders, but a much more diverse set of regions important for prediction. Connectivity of the left caudate nucleus was the main predictor of remission in both men and women.

Conclusions:Initial pharmacokinetic indicators of response to antidepressant treatment in LLD can differ significantly between men and women. Simply including gender as a covariate in the model is not enough to capture these differences, as there is a clear moderating effect of gender. Separate models for men and women or gender interaction terms by region may be needed to provide sufficient sensitivity and specificity.

Key words:Depression in old age, functional connectivity at rest, response to antidepressants, predictive models, gender differences

Disclosure:Nothing to disclose.

Kyle Decker*, Nausheen Baig, Stephen Murata, Angelos Halaris, Jawed Fareed, Debra Hopppenstaed

Loyola University School of Medicine, Saint Charles, Illinois, USA

Background:Inflammation is associated with major depressive disorder and treatment resistance. These advances have stimulated the search for predictive biomarkers of treatment response. The systemic inflammatory immune index (SII) has shown promise as a prognostic indicator for solid malignancies and cardiovascular disease, while its use in psychiatric disorders remains unexplored. In a recent randomized, double-blind, placebo-controlled study, we found that combination therapy of celecoxib (CXB) and escitalopram (ESC) was more effective in reversing treatment resistance and increasing response to treatment-resistant bipolar depression (TRBDD ) compared to antidepressant treatment was with ESC plus placebo. Our follow-up analysis characterizes treatment response in terms of irritable bowel syndrome, inflammation, and kynurenine (KP) pathway biomarkers.

Methods:The sample (N = 69) consisted of 65.2% women, 65.2% white, mean age 42 years (SD = 12.7). The study included healthy controls (n = 32) and TRBDD subjects (n = 47). The TRBDD group consisted of an ESC + CBX arm (n = 26) and an ESC + PBO arm (n = 21). SII was calculated from the complete blood count with differential (IBS = platelets x neutrophils/lymphocytes) at baseline and at completion (8 weeks). Plasma levels of KP and inflammatory markers were also determined at baseline and week 8. Severity of depressive symptoms (main outcome) was measured continuously (HAMD17 total score) and dichotomously (treatment remission, defined as HAMD17 total score < 7 at week 8). Statistical analysis was performed using R-3.6.3.

Results:Group comparison revealed no significant differences in IBS by baseline treatment arm or remission status at week 8. Baseline IBS showed a trend with an elevated profile of inflammatory cytokines, including higher baseline IL-2 (p=0.073), baseline IL-1B (p = 0.051), hsCRP at week 8 (p = 0.08) and lower anti-inflammatory IL-4 (p = 0.086). Baseline IBS was significantly correlated with a lower baseline vascular endothelial growth factor (VEGF) level (p = 0.029). In the multivariate linear model (adjusted R2/R2 = 0.49/0.41), HAMD17 at week 8 (outcome) was significantly associated with ESC+CBX treatment (p<0.008), an interaction with age and baseline of SII (beta estimate  = 0.001 , (95% CI [  < 0.001, 0.001]), p  < 0.001, Cohen's D  = 0.5). In a separate model using individual cell counts (R2/adjusted R2 = 0.413/0.334), HAMD17 at week 8 was associated with baseline neutrophil counts in elderly patients (b-estimate = 0.17 (95% CI). [ 0.06, 0.27 ]). , p < 0.003, Cohen's D = 0.48), but no platelet or lymphocyte counts at baseline (p = 0.312 or p = 0.201)

Conclusions:In univariate analysis, baseline IBS showed a trend with elevated pro-inflammatory markers (IL-2, IL-1B, hsCRP) and lower anti-inflammatory markers (IL4). IBS correlated significantly with lower vascular endothelial growth factor (VEGF), which is associated with neuroprotection and previously shown to be elevated in our TRBDD cohort compared to healthy controls. In elderly patients, less pretreatment IBS predicted less depressive severity at week 8, regardless of treatment arm, and this association appeared to be largely determined by the neutrophilic component of IBS. Taken together, IBS appears to be a useful predictor of poor prognosis in TRBDD. Future studies with larger sample sizes should further explore the potential clinical utility of IBS because it is readily available and accessible through routine blood counts.

Key words:Bipolar depression, treatment resistance, inflammation

Disclosure:Nothing to disclose.

Katharine Dunlop*, Logan Grosenick, Jonathan Downar, Fidel Vila-Rodriguez, Faith Gunning, Zafiris Daskalakis, Daniel M. Blumberger, Conor Liston

University of Toronto, Toronto, Canada

Background:Major depressive disorder (MDD) is associated with considerable variability in symptoms; A comprehensive understanding of this variability can lead to individualized intervention approaches and therefore to better treatment response rates. Recent efforts by our group and others have attempted to understand the heterogeneity of symptoms in MDD using functional neuroimaging. Although these recent studies represent a significant advance in understanding heterogeneity in MDD, replication and validation of these results are critical given the limitations imposed by sample size and depth of clinical characterization. To address these limitations, this study has three objectives. First, we seek to understand the neurobiological basis for the heterogeneity of MDD symptoms by extending our previous work in defining robust and reproducible dimensions of brain behavior to new data. An L2 norm regularized multivariate model was constructed using a large MDD dataset recruited from a single site and containing additional items to assess anhedonia and anxiety symptoms. Second, we tested for the existence of MDD subtypes and assessed their stability and reproducibility. Third, we characterized these MDD subtypes in terms of atypical resting-state functional connectivity (RSFC), clinical symptoms, and antidepressant response to noninvasive brain stimulation.

Methods:L2 Regularized Canonical Correlation Analysis (RCCA) was performed on a large MDD dataset from a single site (n = 328, 215 women (65.6%); mean age = 40.35 ± 12.05 SD) using CSR and clinical symptoms evaluated. To optimize three RCCA hyperparameters, we first perform a nested trellis search (with training, validation, and testing partitions); The optimal combination of hyperparameters was defined as the highest average canonical correlation in the preserved holdout data for the first dimension. We then examined the stability and retention performance of the dimensions (on test data not used for training or validation) and tested the significant dimensions using random permutation tests. We then generate a final optimized RCCA model and evaluate the performance and stability of hierarchical clustering. By identifying the optimal clustering solution, we characterized latent variables representing co-occurring CSRs and symptomatology and symptom/CSR differences by subtype. Finally, we identified subtype differences in response to repetitive transcranial magnetic stimulation and remission rates.

Results:The performance and stability of the first three dimensions of the RCCA were significant (p < 0.05, random permutation test). These three dimensions represented: depressed mood and RSFC pattern and thalamus mode; anhedonia and higher order visual and cingulo-opercular network and CSR; and insomnia and sensorimotor posterior insula and RSFC, among other connectivity functions. Hierarchical clustering identified four significant subtypes of depression (p<0.05, randomized permutation test), each with distinct clinical symptom profiles, abnormal CSR patterns, and responsiveness to repetitive transcranial magnetic stimulation (rTMS) in the precranial cortex. frontal, dorsomedial, or dorsolateral. Subtypes with less anhedonic symptoms responded better to rTMS. Subtypes did not differ by age or sex.

Conclusions:In an extension of our previous work, we attempted to characterize regularized CCA and clustering performance on a large MDD dataset from a single location. RCCA revealed three significant, stable, and generalizable dimensions of brain behavior that resembled well-documented brain associations of MDD symptoms and four categorical subtypes. Categorical and dimensional approaches to analyzing heterogeneity can be beneficial in different contexts. We considered several study design options that may affect RCCA models, including participant inclusion/exclusion criteria, medication use, and choice of measures based on symptom severity. Together, these results represent an important step forward in evaluating data-driven subtyping methods and provide evidence that the RCCA is a powerful tool for identifying robust and generalizable associations between RSFC and behavior.

Key words:Functional connectivity at rest, subtypes of depression, transcranial magnetic stimulation, canonical correlation analysis (CCA)

Disclosure:Nothing to disclose.

David Pagliaccio*, Emily Zhang, Alma Bitran, Kenneth Wengler, Guillermo Horga, Randy Auerbach

New York State Psychiatric Institute, Columbia University, New York, New York, United States

Background:Depression is a chronic and damaging mental illness that usually peaks in adolescence. Previous work has implicated changes in RDoC-positive valence systems in adolescent depression, including anhedonia and the blunted striatal reward response. These changes are usually based on dopaminergic projections from the substantia nigra and ventral tegmental area in the midbrain to the striatal and prefrontal circuits, respectively. However, the hypothetical role of dopamine is largely based on animal studies, pharmacological studies, postmortem examinations in humans, and studies in adults using methods too invasive for pediatric examinations (eg, lumbar puncture, positron emission tomography). Recently, a safe, non-invasive alternative means of characterizing midbrain dopamine using magnetic resonance imaging (MRI) has been developed to assess neuromelanin, an important by-product of dopamine metabolism.

Methods:As part of ongoing data collection, we are collecting high-resolution neuromelanin MRI data from adolescents (13-18 years; target N =60; no exclusions based on gender or sex), primarily with a history of major depressive disorders . Complete clinical assessment of the adolescent, self-report and data collection by smartphone in the following months. Preliminary analyzes include linear regression models on N = 29 adolescents. All analyzes controlled for age, sex and head movement.

Results:Adolescents with current depression have a reduced neuromelanin signal in the substantia nigra pars compacta (b = -1.88, t = -2.51, p = 0.02). A lower SNpc neuromelanin MR signal is associated with more severe depression (CDRS; B = -0.45, t = -2.67, p = 0.01), social anhedonia (ACIPS; B = -0.46, t = -2.89, p = 0.009 ) and suicidal ideation (SSI; B = -0.59, t = -4.23, p < 0.001.

Conclusions:These new data support a role for midbrain dopaminergic deficits in adolescent depression. Ongoing analyzes will explore associations with real-world affect and anhedonia via smartphone ecological snapshot assessments, as well as associations with other neuroimaging modalities, i.e. H. Association of midbrain neuromelanin with reward response during fMRI. Our aim is to test the usefulness of neuromelanin MRI in combination with other measures as predictors of the course and persistence of depressive symptoms during this period of rapid adolescence. Future studies will build on this to examine potential dopaminergic risk markers in early childhood development to predict the onset of depression before this peak in adolescence.

Key words:Adolescent depression, anhedonia, neuromelanin-sensitive MRI, MRI

Disclosure:Nothing to disclose.

Arianna Rizzo - Zelai Garcon-Poca (official music video) Emilya Ventriglia - Jordi Bonaventura (official music video)

National Institute on Substance Abuse, Baltimore, Maryland, USA

Background:Opioids have long been used and studied for their analgesic properties, and synthetic mu-opioid receptor (MOR) agonists are the most effective analgesics available. However, these drugs have known side effects, including constipation, respiratory depression, and abuse potential. Therefore, there is an urgent need to develop new MOR agonists with reduced side effect profiles. A crucial tool for such an effort is the development of a selective MOR radiotracer for in vivo target acquisition studies using positron emission tomography (PET). The only selective PET radiotracer for MOR developed so far is [11 C]carfentanil. [11 C]Carfentanil has been used in many studies to measure ROM binding in humans and laboratory animals. Despite its use, [11 C]carfentanil has two major limitations. It has a very high power, which makes it necessary to reach a very high specific activity in its radiosynthesis, and its use is limited to PET studies in centers with in situ cyclotrons. Consequently, an 18F-labelled MOR selective agonist PET radiotracer with a longer half-life and lower potency than [11 C]carfentanil would be desirable, but such a radiotracer has not been developed to date. Etonitazen is a potent and selective MOR agonist that has not been extensively studied. The aim of these studies was to characterize a new analogue of fluorinated etonitazene (also known as fluoronitrazene, FNZ) and to evaluate its potential for radiolabeling and use as an in vitro 3H-labeled 3H-labelled MOR-selective radioligand and 18F-labeled PET radiotracer.

Methods:To assess its selectivity, FNZ was tested against a panel of >100 receptors and enzymes at concentrations of 100 nM and 10 µM. To assess its propensity to enter the brain, FNZ was also tested for its drug transporter inhibitory activity against a panel of different drug transporters using the same concentrations. FNZ and [3H]FNZ were analyzed by competitive binding assays using suspensions of rat brain membrane (minus cerebellum) (40 µg protein/ml) diluted in 50 mM Tris-HCl (pH 7.4) containing 10 mM MgCl2 , 10 nM [3H]DAMGO (46 Ci/mmol) or 1 nM [3H]FNZ (43 Ci/mmol) and increasing concentrations of test compounds (DAMGO, FNZ) were incubated for 2 hours at room temperature. Non-specific binding was determined in the presence of 100 µM naloxone. In all cases, free and membrane-bound radioligands were separated by rapid filtration in a 96-well plate collector and washed with 2 ml of ice-cold Tris-HCl buffer. Microscint-20 scintillation fluid (65 µl/well) was added to the filter plates, incubated overnight, and radioactivity counts determined in a MicroBeta2 plate counter. Competition curves at one site were fitted and Ki values ​​were calculated using the Cheng-Prusoff equation. FNZ was also tested for its ability to stimulate cAMP and β-arrestin signaling using HEK293 cells transfected with hMOR cDNA and the corresponding genetically encoded sensors.

Results:At 10 µM, FNZ inhibited binding to serotonin (5-HT1A, 5-HT2A, 5-HT2B), adrenergic (α1A, α1D), cannabinoid (CB2), opioid (delta, kappa, MOR) and calcium (L-type, diltiazem site) and potassium channels (hERG). At 100 nM, FNZ only inhibited MOR binding. In the efflux transporter panel, FNZ at 10 µM inhibited transporter activity of OCT2, BSEP, MATE1, MATE2-K, OAT3, OATP1B1, OATP1B3 and p-glycoprotein (P-gp). At 100 nM, FNZ only inhibited the activity of OCT2 and MATE2-K, which are peripherally restricted. Competitive binding assays against [ 3 H]DAMGO showed that FNZ had a Ki = ~1.0 nM. Likewise, [3H]FNZ showed a Kd = ~1.3 nM. FNZ showed an EC50 of ~0.1 nM and Emax of ~100% for cAMP and an EC50 of ~10 nM and Emax of ~100% for β-arrestin.

Conclusions:FNZ is a selective MOR agonist and [3H]FNZ shows favorable properties as a radioligand in vitro. FNZ shows minimal interaction with peripherally expressed efflux transporters and may therefore have potential as a PET radiopharmaceutical.

Key words:Mu opioid receptors, functional characterization, fluoronitrazene

Disclosure:Nothing to disclose.

Brenna Williams*, Anuj Patel, Zoe Frank, Maellie Midroit, Hailey Huddleston, Patrick LaChance, Michael J. Frank, Kevin G. Bath

Columbia University, New York State Psychiatric Institute, New York, New York, United States

Background:Parkinson's disease results from decreased striatal dopamine (DA), resulting in motor deficits such as bradykinesia, akinesia, and tremor. Theoretical models suggest that the source of these deficits is not in motor performance per se, but in motivation, where DA depletion increases the cerebral representation of the cost of action. Furthermore, DA depletion not only induces a performance effect (reinforcement of motivational costs), but is also associated with failed learning, such that motor performance decreases with increasing experience, as costs are learned in context. . Experimental studies in which DA blockade or depletion was manipulated separately during the learning and performance phases provided strong evidence for the hypothesis of aberrant learning resulting from D2 receptor misbinding in the indirect corticostriatal pathway. GPR6, a G protein-coupled receptor, is highly specifically expressed in D2-containing human and murine striatopal neurons; Therefore, manipulation of the GPR6 function offers a new way to intervene in the faulty learning process. However, the mechanisms by which GPR6 affects performance or learning remain unknown. Given the putative role of GPR6 in plasticity-dependent processes, along with its selective expression in D2 cells, we predicted that loss of GPR6 would reduce mallearning under pharmacologic DA receptor blockade and lead to paradoxically faster recovery after drug withdrawal , than observed . in wild mice.

Methods:Motor learning and performance decline in male and female wild-type C57BL/6N and GPR6 KO mice (n=8-10/group/sex) were studied in a rotarod accelerator to assess the effects of receptor antagonists. D1 and D2 (including a D1/D2 cocktail) on acquisition of a new motor learning task and subsequent performance when stopping the drug. Experiments are being conducted to test animals for biochemical markers of plasticity. Building on previous studies on reinforcement learning and our knowledge of the signaling pathways affected by GPR6, we will specifically look at activation of plasticity markers DARPP-32, CREB, and MAPK.

Results:We found that DA receptor blockade impaired motor performance and that the D2 and D1/D2 cocktail, but not D1 blockade alone, significantly impaired motor performance recovery after drug withdrawal. All mice showed impaired performance with dopamine antagonists (days 1-5, "direct effects on performance"). After drug removal (D2 or D1/D2 cocktail), wild-type mice showed slower recovery (WT + drug vs. WT/KO + Salt, repeated measures, one-way ANOVA, post-hoc Tukey: days 8- 12, p < 0.05). Consistent with our hypotheses, GPR6 KO mice performed better after drug removal and showed more rapid and complete progression to "normal" performance compared to wild-type mice (GPR6 KO + drug vs. WT/KO + Salt, one-way ANOVA com Repeated measurements: days 8–9, p<0.05, D10–12, ns). This effect was most dramatic under conditions where both D1/D2 receptors were blocked. Notably, GPR6 did not affect the direct performance effects of DA receptor blockade and therefore appears to selectively affect the defective learning component (GPR6 KO + drug vs. WT + drug, One-Way Repeated Measures ANOVA: Days 1–5, ns).

Conclusions:Collectively, these data show that loss of GPR6 receptors diminishes the behavioral learning effects that occur under D2 blockade, suggesting that variation in GPR6 function modulates the extent to which aberrant learning occurs through cellular plasticity. Future experiments should clarify whether motor learning under D2 blockade in wild-type mice leads to increased activation of proteins involved in plasticity in D2-positive cells. We hypothesize that loss of GPR6 will attenuate motor learning-induced expression of phosphorylated DARPP-32, CREB, and MAPK, indicating reduced plasticity of D2-positive cells. These results provide evidence that GPR6 represents an understudied but promising target and pathway for intervention in several frontostriatal disorders that impair motor, motivational, and cognitive functioning, including but not limited to Parkinson's disease.

Key words:Neuropsychiatric disorders [schizophrenia, Parkinson's disease, major depressive disorder], dopamine, GPCR, motor learning

Disclosure:Nothing to disclose.

Dibyadeep Datta*, SueAnn Mentone, Yury Morozov, Rosalinda Roberts, Christopher van Dyck, Amy Arnsten

Yale University School of Medicine, New Haven, Connecticut, USA

Background:Tau pathology in Alzheimer's disease (AD) targets higher cortical circuits, with evidence that phosphorylated tau spreads from the entorhinal cortex (ERC) to "seed" pathology throughout the neural network. Recent findings indicate that threonine-217-phosphorylated tau (pT217-tau) can be detected in cerebrospinal fluid (CSF) and plasma as an early biomarker of subsequent diseases. pT217 tau levels correlate with disease stage, progression, and longitudinal rates of change. Importantly, pT217-tau CSF allows early identification of pre-symptomatic individuals at risk and shows high specificity for conversion to mild cognitive impairment and dementia. Recently, pT217-tau blood plasma has been shown to distinguish AD from other neurodegenerative diseases with high diagnostic accuracy (>98%) and was more accurate than blood tests for pT181-tau, neurofilament light, or Aβ-42 ratio./ 40. Lifetime pooled pT217-tau plasma correlated with neuropathological neurofibrillary tangled (NFT) density measured post mortem. CSF and plasma pT217-tau increase approximately 7-fold in AD, with levels increasing 20 years before the onset of cognitive decline. Recent high-resolution quantitative proteomic mapping of post-translational modifications (PTMs) on multiple tau isoforms has revealed that pT217-tau is a crucial epitope that distinguishes AD from other neurodegenerative diseases and indicates disease progression. However, the role of pT217-tau in brain tau pathology is unknown, particularly as soluble tau species are dephosphorylated post mortem in humans. Rhesus macaques naturally develop the same qualitative pattern and sequence of tau and amyloid pathology, with NFTs composed of paired helical filaments, identical to human AD. Perfusion fixation of monkey tissue preserves the phosphorylation state and allows imaging of molecular localization and interactions with nanometer resolution, which is not possible in humans due to postmortem degradation. The current study examined the ultrastructural localization of pT217-tau in layer II ERC of aged rhesus monkeys and focused on possible evidence of interneuronal spread and exposure to the extracellular space.

Methods:We used immunohistochemistry to examine the pattern of anatomical localization of pT217-tau in aged rhesus monkeys and compared with subjects with postmortem AD. We performed high-resolution immune electron microscopy (immunoEM) in old rhesus monkeys (18-31 years) to localize pT217-tau in stellate cell islets in layer II of CKD, which show the first signatures of tau pathology in AD.

Results:Our light data demonstrate dense immunostaining of pT217 tau in CKD layer II stellate cells, hippocampal pyramidal cells CA3, CA1 and dlPFC layer III pyramidal cells, all with tau pathology in human AD. The label shows filamentous fibrillated structures aggregated within apical dendrites and basilar dendrites, often with a twisted morphology common in NFTs. Immunostaining of pT217-tau was predominantly seen in postsynaptic compartments in layer II of the monkey ERC. pT217-tau accumulates in the spinal apparatus of the calcium-storing smooth endoplasmic reticulum near axospinous asymmetric glutamatergic synapses in dendritic spines. We observed extensive transsynaptic pT217-tau trafficking between interconnected neurons within omega-shaped bodies and endosomes in layer II of the ERC, particularly near excitatory but not inhibitory synapses. Within the dendritic spindles, pT217-tau aggregated into microtubules, often consistent with autophagic vacuoles, indicating neuritic dystrophy.

Conclusions:pT217-tau accumulates in layer II subcompartments of the ERC, known to be the first to show pathology in humans. The data provide the first evidence for the transport of pT217-tau between neurons to "seed" tau pathology into higher brain circuits, which can interact with the extracellular space to become easily accessible and captured in the CSF and blood as the biomarkers. Elucidating patterns of neurodegeneration with pT217-tau could potentially guide early intervention of treatments that can attenuate tau hyperphosphorylation in AD.

Key words:Alzheimer's disease, tau, entorhinal cortex, protein trafficking, neurofibrillary tangle

Disclosure:Nothing to disclose.

Matthew Klein*, Wen-Hsuan Chan, Molly Lucas, Srinivasan Vairavan, Abigail Bangerter, Nikolay V. Manyakov, Gayle Wittenberg, Gahan Pandina

Janssen Research and Development, San Diego, California, USA

Background:Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impaired social communication and restricted and repetitive behavior. It often occurs in combination with other psychiatric disorders. There are no approved medications for the core symptoms of ASD, in part because of the wide variation in symptom presentation. Stratification of heterogeneity may allow for more targeted interventions. There are currently no validated biomarkers for ASD. N170, an early-stage neural response to faces, has been proposed as a potential stratification biomarker. Longer latency or slower response to faces were linked to social communication skills, making it a relevant candidate. To be useful in clinical trials, biomarkers must also be reliable and robust. To advance the validation of N170 as a biomarker, the results must be reproducible in the context of use. In this abstract, we present an event-related potential (ERP) study for N170 that was conducted in a large sample of typically developing (DD) children and adults with autism in a clinical trial. In addition, we used age-matched models to create subgroups based on N170 response and examine whether there are phenotypic differences between groups.

Methods:Biosensor data, including electroencephalogram (EEG), were collected from participants with ASD (n=144) as part of a series of passive visualization tasks at 3 time points (0, 4, 8 weeks) during an observational study (NCT02668991 ). Data from a group of DT participants (n = 41) were collected at a single time point. To project the facial task, static stimuli of erect faces with direct or deviated gaze were presented. EEG recording was performed using the ActiCHamp 32 with 19 electrodes placed according to the standard 10-20 system. ERPs were calculated for periods ranging from 200 ms before the start to 1000 ms after the start of the stimulus. ERPs were calculated by stimulus type after subtracting the baseline 200 ms before stimulus.

We focused on N170 at the parieto-occipital sites (P7, P8, O1, O2). We calculated differences between groups (all ages, 6-12, 12+) in mean N170 peak latency and amplitude, including gender and age as covariates. We assessed the stability of these measures for the ASD group at 3 time points using the intraclass correlation coefficient (ICC) of a mixed linear model. Correlations between ASD N170 traits and phenotypic data (IQ, ADOS, Autism Behavior Inventory) were calculated. Finally, we used a linear mixed-effects model to estimate age-adjusted N170 latencies for the DT and ASD groups and calculated the remaining differences between expected and measured N170 latencies (Webb, 2022). Using a 90th percentile cutoff based on TD residuals, we classified participants with ASD into "slow" or "standard" groups. This approach allowed us to stratify ASD subgroups and evaluate these subgroups defined by N170 latency in terms of phenotypic behavior.

Results:The final number of participants with data for analysis was TD 30/ASD (97, 95, 91) for each respective time point, TD 15/ASD (43, 47, 38) and TD 15/ASD (54, 48, 53 ) . ) each for the age groups under and over 12 years old. There were no differences between groups regarding condition (facing or facing forward). For the all age group, there was a group difference of N170 for all faces, with the ASD group having longer latency and reduced amplitude. The latency group difference was maintained when age and gender were included in the analysis and when groups were analyzed by age. The ICC value was 0.81 (0.61 and 0.85 for children under and over 12 years of age), indicating moderate stability at 4 and 8 weeks for N170 latency measured in TEA. There were no correlations between N170 latency and phenotypic data except a small negative correlation with narrow interests observed at all 3 time points. We observed significant differences in the analyzes of ASD subgroups defined by latency (slow/standard). Greater severity of basic ASD behavior was observed in children under 12 years of age in the slow N170 group, and greater irritability was associated with the standard N170 group in children over 12 years of age. There was a difference in IQ between the subgroups, with a slower response being associated with a lower IQ.

Conclusions:These results are an important step towards demonstrating the reliability and latency robustness of N170 as a potential stage biomarker for ASD. The relationships observed between the subgroups and the severity of the main ASD symptoms in the younger age group confirm the relevance of this biomarker for the ASD phenotype. The relationship of this biomarker with age and IQ needs further research.

Key words:Autism, EEG, N170, biomarkers

Disclosure:Janssen Research and Development, LLC - Employee (self-employed), Johnson and Johnson - Stocks/Stocks (self-employed)

Srinivasan Vairavan, Savannah Gosnell, Abigail Bangerter, Matthew Klein, Molly Lucas, Nikolay V. Manyakov, Gayle Wittenberg, Gahan Pandina*

Johnson and Johnson, Titusville, New Jersey, USA

Background:Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by impaired social communication and restricted and repetitive behaviors/interests. Other psychiatric comorbidities are common in ASD. Variability in the etiology and phenotypic outcomes of ASA contributes to clinical heterogeneity. Identifying subtypes that maximize homogeneity using clinical features could potentially improve detection of changes in response to treatment. In this review, we identified clinical subtypes in ASD using 5 core domains (ie, social communication, restrictive behavior, mood and anxiety, self-regulation, and challenging behavior) as part of the Autistic Behavior Inventory (ABI) and replicated results in two different cohorts.

Methods:The ABI baseline data come from three large studies, including an online survey, an observational study (NCT02668991) and an efficacy study (NCT03664232). The age, gender, and symptom severity (5 main domains in the ABI) of individuals with ASD were subjected to a concordant propensity score in three studies with the efficacy study as the reference, resulting in a sample size of 180, 45, 45 online. Research, observational study or efficacy study. The distribution of intelligence quotient (IQ) across studies was comparable with a mean IQ ≥ 90. The 5 core domains of the ABI underwent dimensionality reduction based on Uniform Manifold Approximation and Projection (UMAP). The number of groups was data driven using our proprietary gaps metric. The UMAP parameters, i. H. The number of neighbors and the minimum distance were optimized based on the distance between the training group and the validation group, calculated as the average distance of each point in the training group (online survey). Centroid minus the mean distance of each point at hold. Cluster (observational study) in the training cluster focus. The UMAP parameters corresponding to the minimum number of groups corresponding to the three main positive distances between the training group and the validation group were chosen as optimal parameters.

Results:Three groups with high, intermediate, and low reporting of symptoms in different domains on the ABI were identified and remained stable across the validation (observational study) and testing (efficacy study) datasets.

Conclusions:These results highlight the clinical subtypes inherent to ASD using ABI. The stable profile of three groups in ASD will be evaluated further in the efficacy study to understand the enrichment in response to treatment. In addition, the profile of three groups will also be evaluated for the enrichment of observed digital signatures through heart rate variability, evoked response (N170 corresponds to the neural processing of faces), eye tracking and facial expressions.

Key words:Autism, ASD, ABI

Disclosure:Johnson and Johnson - Equity/Equity (self-employed), Janssen Research and Development, LLC - Employee (self-employed)

Lilly Schwieler*, Jacob Ahlberg Weidenfors, Vytautas Griška, Xueqi Li, Fredrik Piehl, Aukse Mickiene, Sophie Erhardt

Karolinska Institute, Stockholm, Sweden

Background:Tick-borne encephalitis (TBE) is caused by neurotrophic flavivirus infection and is one of the most serious tick-borne neurological diseases. Patients with TBE present with long-term post-encephalitic neurological and neuropsychiatric symptoms, including cognitive impairment. Importantly, there are currently no clinical biomarkers and targeted treatments for post-encephalitic symptoms. It is well known that viral infections induce tryptophan degradation through a cascade of enzymatic steps known as the "kynurenine pathway" (KP). Modulation of kynurenine metabolites during infection represents an improved system for regulating immune responses. This KP is also responsible for the biosynthesis of neuroactive compounds such as quinolinic acid (QUIN) and kynurenic acid (KYNA), both capable of influencing cognition . Indeed, altered KP activity has been repeatedly demonstrated in various diseases in which patients suffer from cognitive impairment. CSF-KYNA is associated with cognitive problems and psychosis in psychiatric disorders, whereas CSF-KYNA and QUIN levels in HIV-1 infected patients and in patients with COVID-19, disorders with a high incidence of long-term cognitive dysfunction, are increased. The present study aims to measure KP metabolites in the cerebrospinal fluid (CSF) and serum of patients with TBE and to investigate their relationship with long-term neurocognitive performance.

Methods:TBE patients were recruited upon admission to the Hospital of the Lithuanian University of Health Sciences, Kaunas, during which time serum and CSF samples were collected and the severity of brain disease was classified as mild, moderate or severe according to clinical criteria. At two follow-up visits, 6 and 18 months after hospital discharge, patients underwent neurocognitive performance tests (MATRICS Consensus Cognitive Battery, MCCB) and additional serum samples were collected. Serum and CSF concentrations of tryptophan, kynurenine, KYNA, QUIN, 3-hydroxykynurenine, picolinic acid, and nicotinamide were measured by ultrastrong liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in patients with TBE and non-inflammatory neurological diseases illnesses. Disease Control Group (NINDC). After data collection, a statistical analysis was performed to examine the relationships between KP metabolites and neurocognitive performance and patient symptoms. Linear regression models using log-transformed metabolite concentration data were used to assess differences in KP metabolite levels between control and TBE patients of different clinical severities. Interactions between measured levels of the KP metabolite and neurocognitive performance were assessed using Spearman's rank correlation tests.

Results:TBE patients (n=87, mean age 53, mean BMI 25.9, 39% women) were not significantly different from NINDC controls (n=12, mean age 52.5, mean BMI 25.3, 58% women) in in relation to age, sex and BMI.

Statistical analysis showed an extensive induction of KP in TBE patients compared to the control group. In CSF, concentrations of all kynurenine metabolites increased significantly with notably dramatic increases in the neurotoxic metabolite QUIN (TBE: median 544.24 nM (222.85; 1199.63), NINDC: median 10.31 nM (7.82 ;11.29), p<0.001). The kynurenine/tryptophan ratio (rKT), an indicator of kynurenine signaling pathway activity, was markedly increased in the cerebrospinal fluid of patients with TBE. Similar changes in KP activity were seen in the serum of patients with TBE, with increases in all measured kynurenine metabolites and notable exceptions in KYNA and QUIN. Interestingly, serum rKT remained significantly elevated in TBE patients for up to 18 months, indicating prolonged and sustained activation of KP in TBE patients. Furthermore, increasing disease severity was associated with a significant increase in CSF kynurenine and rKT.

Conclusions:Our results show KP inductions in both serum and CSF of TBE patients with persistent serum rKT that has not returned to normal 18 months after infection. Statistical analyzes showed the importance of the magnitude of KP induction for performance in different neurocognitive domains in patients with EBT measured at 18 months. Confirmation that kynurenine metabolites are elevated during TBE infection and understanding their role in symptomatology and cognitive decline may open up new treatment interventions aimed at decreasing activity in the kynurenine pathway.

Key words:Cognitive impairment, viral infection, kynurenine pathway

Disclosure:Nothing to disclose.

Juan Molina, Joyce Sprock, Dylan Iwanaga, Jo Talledo, Yash Joshi, Bradley Voytek, Lisa Delano-Wood, Christopher Gonzalez, Steven Huege, Gabriel Leger, Greg Light, Neal Swerdlow*

University of California, San Diego, La Jolla, California, USA

Background:It has been proposed that the balance of cortical excitatory and inhibitory synaptic activity ("E/I balance") is a critical mechanism for adjusting neural network activity within the narrow time window associated with the processing of sensory stimuli. Several studies have suggested that aberrant E/I balance in Alzheimer's disease (AD) may: 1) reflect cortical glutamatergic, cholinergic, and GABAergic transmission pathology; 2) contribute to cognitive impairment in this disorder; and 3) be a target for AD therapy. The study of E/I balance often requires invasive methods such as B. Single unit recordings or voltage clamp in rodents and/or non-human primates which have excluded its use in human studies. Recent results suggest that the aperiodic, 1/f-like component of neural power spectra may indicate tonic E/I balance and can be probed non-invasively using electroencephalographic (EEG) recordings. Using this approach, we report that the non-competitive NMDA receptor antagonist memantine (MEM) normalizes E/I balance in patients with schizophrenia. MEM is used clinically to treat moderate to severe Alzheimer's disease (AD); As part of a longitudinal study of predictors of MEM susceptibility biomarkers in AD, we evaluated the effects of acute MEM (0 vs. 20 mg, po) on E/A balance in 18 AD patients.

Methods:Previous subjects are 18 carefully selected individuals with AD (mean (range): age = 72.8 (61-82 years); MoCA = 16.4 (6-23); education = 16.6 (12-20 years) ;M:F=9:9). Baseline neurocognitive measures included MoCA and ADAS-cog; The GDS and NPI-Q scales assessed depression and general psychiatric symptoms. Subjects completed a balanced double-blind study of MEM (placebo (PBO) vs. 20 mg; 2 test days 1 week apart) of subjective, autonomic, cognitive, and electroencephalographic (EEG) measurements. At 275 minutes post-pill, neurocognition was assessed using the RBANS. 345 minutes post-pill, EEG measurements were used to assess mismatch negativity (MMN), P3a amplitude, and steady-state auditory response (coherence and 40 Hz power; ASSR). To analyze the aperiodic and periodic EEG spectral properties, the EEG signals were decomposed into their frequency domain components by estimating the power spectral density (PSD) using the Welch method. PSDs from the 4 to 50 Hz range were used to characterize aperiodic "background" or 1/f-like signal and ripple components using a robust linear regression algorithm according to our published methods.

Results:The aperiodic slope (E/I) measurements were reliable, i.e. that is, they were significantly correlated between weeks (R = 0.58, p < 0.015) and were not significantly affected by acute MEM ingestion (F < 1) or continuous use of AChE-I (F = 1, 72 , df 1.16, ns). PBO week H/A scores were not significantly associated with cognition, whether measured using baseline MoCA (R = 0.27, ns) or ADAS-Cog total scores (Basic: R = -0.34, ns; Optional : R = -0.41, ns) or PBO week RBANS score (R = 0.12, ns). PBO week H/A scores were also not significantly associated with baseline GDS (R=-0.375, ns) or NPI-Q scores (R=0.05, ns). The acute effects of MEM on H/A scores were not significant with those of cognition (total RBANS index score; R=0.24, ns) or correlated with MMN, ASSR, or P3a amplitude (all ns). Upon completion of testing, all subjects entered a 24-week open-label study of MEM (10 mg BID), with neurocognitive assessment at 8, 16, and 24 weeks; any predictive effect of E/I measurements on sensitivity to a therapeutic response to MEM is reported.

Conclusions:An EEG-based measure of "excitatory/inhibitory balance" can be detected in AD patients and shows significant test and repeat reliability in these patients. In this modest sample, E/I balance is not associated with neurocognitive deficits at baseline, is not sensitive to acute challenge with MEM (20 mg), and appears to indicate processes distinct from other evoked EEG measures (MMN, ASSR, and P3a) distinguish ). 🇧🇷 Ongoing studies will investigate whether baseline E/A values ​​or their sensitivity to acute MEM exposure predict therapeutic response in a 24-week MEM study.

Key words:Alzheimer's disease, memantine, excitatory/inhibitory balance

Disclosure:Nothing to disclose.

Calvin Leung, Shoshana Rosenzweig, Brian Yoon, Nicholas Marinelli, Ethan Hollingsworth, Abbie Maguire, Mara Cowen, Michael Schmidt, Jaime Imitola, Ece Gamsiz Uzun, Sofia Lizarraga*

University of South Carolina, Columbia, South Carolina, EUA

Background:Autism Spectrum Disorder (ASD) affects 1 in 44 children. Chromatin regulatory proteins are overrepresented among genes that carry high-risk variants in ASD. Disruption of the chromatin environment leads to widespread dysregulation of gene expression, traditionally considered a mechanism of pathogenesis of ASD-related disorders. Alternatively, changes in chromatin dynamics may also result in dysregulation of alternative splicing, which has not been studied as a mechanism of ASD pathogenesis. The anticonvulsant drug valproic acid (VPA) is a known environmental risk factor for ASD, acting as a class I histone deacetylase (HDAC) inhibitor. However, the precise molecular mechanisms underlying the human neurodevelopmental defects associated with VPA exposure are little understood.

Methods:To analyze how VPA exposure and subsequent chromatin hyperacetylation affect the molecular signatures involved in the pathogenesis of ASD, we performed RNA sequencing (RNA-seq) on human cortical neurons treated with VPA. Male neurons from three independent neuronal inductions at day 65. Differentially expressed genes (DEGs) were detected using the DESeq2 software package (version 1.32.0) (adjusted P < 0.05 and fold shift ≥ |1.5 | ). Differential transcription utilization (DTU) events were identified using the DRIMseq software package (version 1.20.0). Statistically significant DTU events were identified as events with P < 0.05 adjusted after stageR (version 1.14.0) post-processing analysis. Differential alternative splicing events were identified using rMATS (version 4.1.1). Statistically significant differential alternative splicing events were classified as events with FDR < 0.05 and IncLevelDifference ≥ |0.1 | identified . ClusterProfiler (version 4.0.5) was used for functional enrichment analysis (GSEA, GO and DisGeNET) of DEG and DTU events. Significant enrichment results were obtained with a q cut-off value <0.05.

Results:We observed that differentially expressed genes (DEGs) for mRNA splicing, mRNA processing, histone modification and metabolism-related gene pools were enriched. We observed widespread and marked changes in gene expression in VPA-treated samples compared to control samples with 3545 DEG up-regulated and 2663 DEG down-regulated. Additionally, we are seeing a general increase in the number and type of alternative splicing events. Skipped exon (SE) and retained intron (RI) events were the most common splicing events detected in VPA-treated neurons, accounting for 40% and 22% of all events, respectively. Differential transcriptional utilization (DTU) analysis showed that exposure to VPA induces extensive changes in transcriptional isoform utilization in genes important for neurodevelopment. Finally, we found that genes displaying DEGs and DTU overlap with known ASD risk genes.

Conclusions:In summary, our work highlights the importance of the chromatin environment in the regulation of alternative splicing in the pathogenesis of ASD in the context of environmental and potentially genetic risk factors (chromatin regulators).

Key words:Autism, Epigenetics, Alternative Splicing

Disclosure:Nothing to disclose.

Daniel Felsky*, Hyun-Sik Yang

Centre for Addiction and Mental Health, Toronto, Canadá

Background:Effective and tolerable pharmacological treatment of the disease in elderly people with cognitive impairment is a major clinical challenge. Over time, psychological and somatic changes manifest themselves as a wide range of symptoms that require intervention, sometimes with agents that can affect mental or general well-being. Therefore, decisions to start or stop treatment are complex, and little is known about the impact of these decisions on long-term outcomes for patients. We sought to understand how different drug prescribing patterns were associated with cognitive impairment in older adults who developed mild cognitive impairment (MCI) or Alzheimer's disease (AD) dementia.

Methods:1,035 elderly people (age 80.7, sd=7; 71% women) from the Study of Religious Orders and Memory and Aging Project (ROS/MAP) were assessed annually (range 3 to 28 years of follow-up, mean = 9 years) . with 19 cognitive tests. Analyzes only included participants who received a clinical diagnosis of DCL (n=416) or dementia (n=619) at their last study visit. The prescribing status of 47 drug types from 20 broad classes (Medi-Span database coding; for example, Alzheimer's disease drugs such as cholinesterase inhibitors and anti-anxiety drugs such as SSRIs, benzodiazepines, etc. ) at each time point. by direct inspection of the containers. Subjects were divided into five distinct band categories for each type of medication: 1) never prescribed during the study ("never"); 2) mandatory for all field trips ("always"); 3) not prescribed when entering the course, transition to prescribed during the course (“transition to”); 4) prescribed at study entry, transition to non-prescribed ("transition off"); 5) Prescription status fluctuated between [on-off-on] or [off-on-off] ("unstable") at some point during the study. Diagnostic stability trajectories were similarly calculated, identifying individuals who: 1) transitioned from NC to MCI or MCI to AD only; 2) transitioned from a more impaired diagnosis to a less impaired diagnosis at any point during the study. Medication histories were associated with longitudinal rates of cognitive decline (individual random slopes of a mixed linear model for global cognitive composite scores) using ANCOVA adjusted for gender, education, APOE ε4 status, age at baseline, tobacco and alcohol use at baseline. baseline. Baseline self-reported illness, baseline cognitive functioning, baseline depressive symptoms, clinical diagnosis at last visit, and number of follow-up visits. For medication courses that affect cognitive decline, we tested associations for 11 neuropathologies in a subset of 757 subjects with autopsy data including postmortem interval and age at death as additional covariates.

Results:After Bonferroni correction for multiple tests, significant associations with cognitive impairment were found for AD trajectories (F4 = 12, p = 1.5 × 10-9) and anxiolytic medication (F4 = 11, p = 7.6 × 10- 9). For AD medications, the always-on-prescription group (n=30) had the slowest cognitive decline and those who discontinued the medication (n=19) experienced the fastest decline (adjusted post-hoc comparison for p<0.001). Significant differences were also found between the always and transition activated groups (n = 177) versus the unstable group (n = 132); The unstable group had the second fastest cognitive decline after the transition group. For anxiolytics, never-prescribed anxiolytics (n = 847) had the slowest cognitive decline, a significant difference from the unstable group (n = 132) (corrected p < 0.001), which had the fastest decline. In both analyses, the "always off" and "in transition" groups were small: removing these groups from the analysis produced a consensus that unstable medication curves are associated with faster rates of cognitive deterioration than stable ones. . Neuropathologically, associations were seen for AD drug courses and neuritic plaques and neurofibrillary tangles, therefore the transitional group had the highest disease burden, possibly reflecting discontinuation of concomitant use of these drugs at more severe stages of deterioration. The unstable trajectory group showed no difference in pathology compared to those who switched to drugs. For cycles of anxiolytic medication, the unstable group was the only one that significantly differed from the never-treated group and showed an increased number of neurofibrillary tangles (adjusted p==0.013). Finally, AD medication course was weakly associated with AD diagnosis stability over time (Fishers p = 0.054), whereas anti-anxiety trajectories were not (Fishers p = 0.89).

Conclusions:Unstable longitudinal patterns of AD and prescription of anti-anxiety medications are associated with faster rates of cognitive decline, independent of a variety of clinical and biological risk factors. The course of anti-anxiety medication, in particular, has not been associated with the stability of a person's clinical diagnosis, but it may be related to increased accumulation of neurofibrillary tangles. Our results suggest that fluctuations in medication or anxiolytic intake may have an adverse effect on cognitive prognosis, although reverse causality cannot be completely ruled out. More studies are needed to fully understand the possible causal relationships between these fluctuations and the acceleration of decline in older adults with cognitive impairment.

Key words:Cognitive impairment, prescriptions, trajectories, Alzheimer's dementia, neuropathology

Disclosure:Nothing to disclose.

Stephanie Puig*, Ryan Salisbury, Anastasia Yocum, Jill Glausier, David Lewis, Zachary Freyberg, Marianne Seney, Matthew MacDonald, Ryan Logan

Boston University School of Medicine, Boston, Massachusetts, USA

Background:Prevalence rates of opioid use disorder (OUD) have increased dramatically, with many patients treated for OUD relapsed within the first year. Vulnerability to opioid relapse is associated with severely disrupted sleep and circadian rhythms. Therefore, improving the circadian rhythm can be an effective intervention to reduce relapses. Although the relationships between OUD and circadian rhythm disorders have been studied in rodents, understanding of the molecular changes that occur in the human brain of people diagnosed with OUD remains limited.

Methods:We used mass spectrometry-based proteomics to study protein changes in postmortem human brains from OUD and unaffected individuals. Postmortem brains, provided by the University of Pittsburgh School of Medicine, Department of Psychiatry, were collected from individuals diagnosed with OUD and unaffected controls. Subjects were matched for age, sex, postmortem interval (PMI), brain pH, and RNA integrity (RIN). To allow for the analysis of protein expression levels, we used time-of-kill information to construct distributed cohorts on a 24-hour timescale. We collected the nucleus accumbens (NAc) and dorsolateral prefrontal cortex (dlPFC), two highly interconnected structures that are heavily involved in OUD. Quantitative proteomics with TMT was used to measure protein in NAc and dlPFC tissue homogenates and synaptosome fractions. Limma was used to analyze differentially expressed proteins with adjusted and unadjusted p-values ​​and log shifts (logFC).

Results:Identification of rhythmic proteins showed that in homogenates, the total number of rhythmic proteins in subjects with OUD was reduced in both NAc and dlPFC (NAc: 115 rhythmic proteins in unaffected controls versus 56 subjects with OUD; dlPFC: 88 rhythmic proteins in unaffected individuals). 🇧🇷 controls vs. 53 on OUD matters). In contrast, in synaptosomes from individuals with OUD, total rhythmic proteins in NAc and dlPFC were decreased and increased, respectively. Interestingly, rhythmic proteins were very different between groups, both in homogenates and in synaptosomes. Specifically, in synaptosomes, signaling pathways enriched in rhythmic OUD proteins included membrane potential, vesicle-mediated transport, and GPCR signaling, which primarily involved synaptic function. Circadian signaling pathways have also been identified as the best synaptosome-enriched signaling pathways.

Differential analysis of rhythmicity comparing periods, phases, amplitude and variance (R2) highlighted proteins that strictly alter rhythmicity between unaffected individuals and OUD. In NAc proteins 25 and 23, rhythmicity changed in homogenates and synaptosomes, respectively, and most lost rhythmicity. In dlPFC, only 10 and 18 proteins altered rhythmicity in homogenates and synaptosomes, respectively. Interestingly, the changes were evenly distributed in the direction of gaining or losing speed. In NAc synaptosomes, key signaling pathways enriched with time-altering OUD proteins included membrane transport, response to light stimuli, and signaling by Rho-GTPases. In dlPFC synaptosomes, they included platelet growth factor beta signaling, tyrosine phosphorylation, and GTPase signaling.

Conclusions:Our study is the first to extensively analyze OUD-induced changes in protein rhythms in postmortem human brains. Our results demonstrate significantly altered circadian rhythms in synaptic function and signaling in NAc and dlPFC associated with OUD. These results provide insight into the processes that mediate disruptions in circadian rhythm and sleep/wake cycles caused by OUD. Ongoing studies are investigating possible functional connections between these signaling pathways in mouse models of OUD.

Key words:Postmortem human brain study, proteomics, circadian rhythms, opioid use disorder, synaptosomes

Disclosure:Nothing to disclose.

Michael Gregory*, J. Shane Kippenhan, Tiffany Nash, Daniel Eisenberg, Philip Kohn, Zachary Trevorrow, Madeline Hamborg, Oliva Kline, Danya Adams, Carolyn Mervis, Karen Berman

National Institute of Mental Health, Bethesda, Maryland, USA

Background:Williams syndrome (WS) and 7q11.23 duplication syndrome (Dup7) are caused by hemideletion (leaving one gene copy) and duplication (leaving three gene copies), respectively, of approximately 25 genes at chromosomal locus 7q11. 23 . Previous research has shown changes in both functional connectivity and white matter microstructure in WS (ie Gregory 2019, Marenco 2007). However, despite the ability to test the effects of gene dosage in research, comparing individuals with hemideletions with individuals who have duplications of the same set of genes, little research of this type has been performed. Neuroimaging of myelination is a particularly good candidate for such an investigation, as studies in rodents have shown that inactivation of the GTF2I gene affected by these 7q11.23 copy number variations (CNVs) is associated with decreased brain myelination (Barack 2019). Here, we take a data-driven approach to identify structural and functional connectivity abnormalities associated with 7q11 CNVs. at a dose of 0.23 CNV, we identified white matter pathways connecting these regions in each participant, and then analyzed changes in myelination within these pathways, again as a function of gene dose.

Methods:Of 70 participants (WS: N = 20, age = 13.8 ± 4.4, 15 women; typical development: N = 34, age = 14.3 ± 3.8, 21 women; Dup7: N = 16, age =14.8 ± 2.7, 8 women). Quality control measures identified 11 participants whose mcDespot data were inappropriate for processing (four subjects with WS, five subjects with typical development, and two subjects with Dup7). First, for resting-state fMRI data, we used distance-based multivariate matrix regression (MDMR) controlling for age, sex, and exercise to identify brain regions where whole-brain functional connectivity patterns were significantly related to CNV dose ( p < 1 × 10-9). Second, after pre-processing the DTI data to calculate voxel tensors, the significant regions emerging from the first step, resting fMRI MDMR analysis, were inflated to extend into the underlying white matter; These inflated regions were then used as seed regions in probabilistic tractography analyzes using AFNI's FATCAT software to identify white matter tracts connecting each pair of regions in each subject. Only white matter compounds that could be identified in 90% of the participants were included in the analysis. Finally, for each participant, voxel-by-voxel maps of the myelin water fraction (MWF) were calculated from the mcDespot data using the publicly available QUIT pipeline; Mean MWF was calculated in each tract identified by probabilistic tractography in each participant and compared between CNV groups while controlling for age and sex using linear regression in R.

Results:Resting functional connectivity patterns were significantly related to CNV dose in 22 gray matter regions. These regions were predominantly located in areas known to serve visuospatial and social functions, consistent with the neurobehavioral phenotypes observed in individuals affected by these CNVs. Probabilistic tractography identified 50 white matter pathways connecting these regions, which were common in over 90% of participants. MWF in three of these sectors was significantly associated with CNV (gene dose) status. These included pathways connecting the posterior cingulate cortex to the anterior cingulate cortex (p = 0.0018), the right angular gyrus to the right fusiform gyrus (p = 0.0028), and the right parietal lobe to the right prefrontal cortex (p = 0 ,0038 ) connect. The myelination of all three lanes showed a pattern of increased myelination with increasing copy number (Dup7 > typical development > WS). None of the tracts showed the opposite pattern of significantly reduced myelination with increasing copy number.

Conclusions:These data use a multimodal neuroimaging approach to identify structural and functional connectivity changes associated with 7q11.23 CNVs. First, the 22 regions with impaired functional connectivity at rest strongly favor visuospatial and social functioning, which are key components of the neurobehavioral phenotypes of WS and Dup7. Second, in line with previous reports of decreased myelin basic protein in postmortem brain samples from people with WS (Barak 2019), we found that myelination of three pathways connecting these regions increased with increasing copy number 7q11.23. Among the white matter pathways studied, these three are particularly notable for their roles in connecting regions known to be the main centers of structural and functional brain networks, including the posterior cingulate cortex, the anterior cingulate cortex, the angular gyrus, the parietal lobe and the prefrontal cortex. (Oldham 2019), supporting the idea that the genetic mechanisms underlying 7q11.23 CNVs result in impaired myelination and that these neuronal traits may contribute to behavioral phenotypes in WS and Dup7. Future work may better characterize these changes in structural and functional connectivity and relate the findings to neuropsychological or behavioral measures.

Key words:Williams syndrome, 7q11.23 duplication, multimodal neuroimaging, myelin imaging, functional connectivity at resting state

Disclosure:Nothing to disclose.

Inga Antonsdottir*, Mary Ann DeMichele-Sweet, Lambertus Klei, Byron Creese, Clive Ballard, Bernie Devlin, Constantine Lyketsos, Robert Sweet

Johns Hopkins University School of Medicine, Baltimore, Maryland, USA

Background:Neuropsychiatric symptoms (NPS), including delusions or hallucinations (psychosis) and depression, anxiety, and/or irritability (mood disturbance) are common in people with Alzheimer's disease (AD). Symptoms like these contribute to more rapid and severe cognitive decline while causing significant disability, morbidity, and mortality.

Methods:This genome-wide association meta-analysis examined data from people with AD who were assessed using the Neuropsychiatric Inventory or Questionnaire (NPI or NPIQ) and participated in one of the following six source studies: Fundació ACE Barcelona Alzheimer's Research and Treatment Center (ACE /GR @ACE), a consortium of the National Institute on Aging of Alzheimer's Disease Centers (ADC), Eli Lilly and Company (LILLY), the Norwegian, Exeter and King's College Consortium for the Genetics of Neuropsychiatric Symptoms in Dementia (NEXGENS), the National Institute for the Study of Familial Aging in Late-Onset Alzheimer's Disease (NIA-LOAD) and University of Pittsburgh Alzheimer's Disease Research Center (PITT ADRC). The presence of psychotic symptoms (AD + P; hallucinations or delusions) or affective symptoms (AD + A; depression, anxiety, and/or irritability) was indicated if participants had at least one of these symptoms at a visit, as assessed by the NPI or CIPN. A separate GWAS analysis was performed for each of the two phenotypes. The results of the AD+P and AD+A phenotypes were combined and analyzes of heritability and genetic correlation were performed using GenomicSEM.

Results:Data from 8714 people with AD (60.2% women) were analyzed. Of these individuals, 32% had neither psychotic (AD-P) nor affective symptoms (AD-A), 28% had affective but not psychotic symptoms (AD+A; AD-P), 28% had both psychotic and affective symptoms (AD -P). + P; AD + A) and 12% had psychotic but not affective symptoms (AD + P; AD-A). There was a significant association between affective and psychotic symptoms, with affective symptoms present in 70.1% of participants with psychotic symptoms versus 46.9% of participants without psychotic symptoms (χ2= df=1, p<0.001).

There was significant heritability for the AD+P and AD+A phenotypes, as well as for the common phenotype. Based on a prevalence of AD+P and AD+A in AD patients of 0.50 and 0.40, respectively, the estimated h2 on the responsibility scale was 0.23+0.06 and 0.06+0 .07 for AD+P or AD+A. The estimated correlation between the two phenotypes on the scale of responsibility was 0.55+0.44. The estimated h2 on the shared phenotype responsibility scale was 0.155+0.065. The genetic correlation of the common phenotype with AD+P was 0.95+0.31 and with AD+A 0.78+0.64.

When evaluating specific genetic associations, we first compared AD-P with AD+P, where two loci achieved genome-wide importance. One was in ENPP6 (rs9994623, OR (95% CI) 1.16 (1.10, 1.22), p = 1.26 × 10 − 8) and the other in 19q13, which comprised three genes, APOE, TOMM40 and NECTIN2 (notably, rs429358 is one of two SNPs that define the APOEε4 genotype [OR 0.84 (0.79-0.90), p = 2.34 = 10-8]). These results are similar to those previously reported in a GWAS analysis of AD+P, with changes in p-value significance likely due to change in sample size.

Comparing AD-A with AD+A, no SNP has achieved genome-wide importance; however, a locus at 9q31 spanning RAD23B approached significance (rs1805331, OR (95% CI) 0.80 (0.74, 0.87), p = 1.331 × 10-7) and could become significant if the sample size is larger, as measured by probability . probability chart.

When bivariate association tests were performed, no SNP reached genome-wide significance, but three approached significance. The first was at 9q31 via RAD23B (rs1805331, O.R. 0.80 (0.74, 0.87), p = 1.33 × 10-7), a single SNP, rs112368830, at 1q42 (O.R. 1.39 (1 .22, 1.57), p = -2.53 ×0 7) and a third locus at 15q22 (best SNP rs35669194, O.R. 0.78 (0.70, 0.86), p = 6.11 × 10 -7) comprising GTF2A2 and the 3' part of BNIP2.

Conclusions:These results show that common genetic variation explains a significant part of the heritability of both phenotypes. These results confirm previous work on the association of AD+P with a common genetic variation and extend the association to AD+A. Notable is the new finding that the common AD+P/AD+A phenotype is associated with a common genetic variation. The AD+P samples had a higher maximum absolute z-value and a lower minimum p-value than the observed values ​​for AD+A, thus being more environmentally friendly.

We found that bivariate analysis was slightly better at detecting NPS genetic associations in AD than either phenotype alone, depending on the same sample size. This highlights the importance of using a common affective-psychotic phenotype when conducting research on genetic associations of NPS in AD.

Given the near-universal prevalence and adverse impact of NPS in patients with AD, and the relative paucity of effective treatment options, further studies of emerging genetic influences on specific NPS phenotypes have the potential to contribute to better treatments.

Key words:Alzheimer's Disease, GWAS, Neuropsychiatric Symptoms (NPS)

Disclosure:Nothing to disclose.

Hartmuth Kolb*, A. Katrin Szardenings, Wei Zhang, Chunfang Xia, Tamara Berdyyeva, Su-Tang Lo, Mani Salarian, Christian Constantinescu

Janssen Pharmaceutical, San Diego, California, USA

Background:There is growing evidence that neuroinflammation promotes and modulates neuropsychiatric disorders. Microglia play a crucial role as key cellular components of the inflammatory process. Being able to visualize activated microglia in vivo would be a valuable tool for studying neuroinflammation and responses to new targeted treatments in the brain.

Colony Stimulating Factor Receptor 1 (CSF1R) is a tyrosine kinase receptor expressed primarily on macrophages and microglia that regulates microglial activation and density. Thus, it offers a target that can be used not only to measure the degree of inflammation in the brain, but also to develop new effective therapies.

Here we describe preclinical studies of the PET ligand [18 F]JNJ-4249, a selective and potent CSF1R inhibitor.

Methods:The novel ligand CSF1R-PET [18 F]JNJ-4249 was evaluated in a series of standard in vitro assays and in vivo imaging experiments in rodents and non-human primates. To induce neuroinflammation, two preclinical rodent models were introduced. A local neuroinflammatory model was induced by intracranial injection of lipopolysaccharide (LPS) into the striatum of Sprague-Dawley rats. A systemic neuroinflammatory model was induced by intraperitoneal injection of LPS in C57BL6 mice. Both models were examined by imaging with [18 F]JNJ-4249, followed by post-mortem analysis of the brains by IHC (Iba-1) and western blotting (CSF1R). Marker distribution and radiometabolite analysis were studied in non-human primates.

Results:JNJ-4249 is a highly potent (IC50 1.2 nM) and selective (panel of 400 kinases) PET binder. In vivo imaging of healthy mice showed good initial brain uptake and rapid clearance. In a mouse model with locally injected LPS, the increased uptake (30%) on days 2 and 4 after LPS injection (20 µg, right striatum) is reproducible and consistent. On the other hand, injection of LPS 48 h after IP in mice showed a 50% increase in total brain compared to naïve mice. Western blotting of brain tissue shows low levels of CSF1R expression in normal tissue, but increased expression in animals treated with LPS (47 kDa, cytoplasmic domain). A baseline scan in healthy non-human primates shows a similar pattern of uptake and brainwashing seen in rodents. The distribution was moderately homogeneous and showed reversible kinetics. Baseline (240 min) whole brain VT was 12.4 mL/cm3 with a range from 11.1 mL/cm3 (cerebellum) to 15.2 mL/cm3 (frontal). Tracer metabolism was rapid and formed more polar metabolites (65% and 4% of parents remaining at 6 and 60 minutes, respectively).

Conclusions:Preclinical evaluation of [18 F]JNJ-4249 shows that this marker is a suitable candidate for CSF1R brain imaging and has the potential to be used as a biomarker for microglial activation and neuroinflammation. Further experiments in neuroinflammation models are underway in preparation for the first human studies.

Key words:Molecular imaging, CSF1R, neuroinflammation, microglia

Disclosure:Janssen: Employee (himself)

Marcus Kaul*, Rohan Shah, Ricky Maung, Daniel Ojeda-Juárez, Ana Sánchez, Grupo TMARC

School of Medicine, University of California, Riverside, California, USA

Background:Methamphetamine (METH) use is a common comorbidity of human immunodeficiency virus type 1 (HIV-1) infection and exacerbates HIV-associated neurocognitive disorders (HAND). However, the combined pathological mechanisms of METH and HIV-1 are not fully understood. Transgenic mice expressing the HIV-1 brain envelope protein gp120 (gp120tg) share neuropathological features and gene expression patterns with HIV/AIDS patients with neurocognitive impairment.

Methods:Previously, we exposed age-matched female and male gp120tg mice and non-tg controls to an escalating METH escalation regimen (HIV-1 gp120tg SAL n = 16, HIV-1 gp120tg METH n = 14, WT SAL n = 15, WT METH n=18) and analyzed the animals 7 months later, at approximately 12 months of age, using behavioral, neurohistopathological, and gene expression assessments (Hoefer et al., Exp. Neurol. 2015). Both HIVgp120 and METH impaired neurites, synapses and behavioral performance. In this follow-up study, we analyzed calbindin (Calb) and parvalbumin (PV) positive neurons and glial cells in a subset of animals (n = 3 - 4 males and females per experimental group) using quantitative immunofluorescence and quantitative reverse transcription polymerase. chain (qRT-PCR). Statistical analysis used post hoc ANOVA and Fisher's PLSD tests to compare experimental groups.

Results:Calb and PV showed sex-dependent differences in cerebral cortex and hippocampus in terms of number of neurons, amount of cellular marker expression, and response to gp120 and/or METH (RNA and protein) exposure. Likewise, pronounced sexual dimorphism was observed in microglia, including in response to METH. In contrast, astrocytosis showed a sex-dependent difference related to gp120 expression only in the cerebral cortex, but not in response to METH.

Conclusions:In conclusion, exposure to METH and viral gp120 impairs learning and memory function and induces neuropathology in both sexes. Although damage to MAP-2 and synaptophysin-positive presynaptic terminals or neurites does not reveal sexual dimorphism, Calb- and PV-positive interneurons and microglia show significant gender- and brain-region-specific differences in long-term response to METH exposure and HIVgp120 expression.

NIH compliant, MH087332, MH104131, MH105330, DA052209 and DA026306 (P5) for M.K.

Key words:HIV-associated neurocognitive disorder, methamphetamine, substance use disorders, microglial activation, astrogliosis

Disclosure:Nothing to disclose.

Olivia Klein, Jonathan Sikora, Marisol Lauffer, Karina Kruth, Christopher Ahern, Aislinn Williams*

University of Iowa, Iowa City, Iowa, USA

Background:The SCN2A gene encodes the alpha subunit of the neuronal voltage-gated sodium channel NaV1.2, which is required for the generation and propagation of action potentials. Allelic variants of SCN2A are associated with autism spectrum disorders (ASD), intellectual disability and seizure disorders. Loss-of-function mutations, such as B. nonsense mutations, can cause ASD and mental retardation. Missense mutations generate a premature termination codon (PTC) in the NaV1.2 frame and result in functional haploinsufficiency. Therapeutic repair of these missense mutations could restore NaV1.2 sodium channel expression.

Currently, treatment of PTCs is limited to the use of small molecules to promote ribosomal reading of the nonsense codon, often resulting in the generation of a nonsense mutation. These therapies are likely to offer minimal clinical improvement for SCN2A and other ion channelopathies, as many ion channels are mutation intolerant, and nonsense mutations in NaV1.2 are strongly associated with epileptic encephalopathy.

We generated a new mouse model of an SCN2A PTC, R1626X, as well as a human patient-derived neural model of another PTC, C959X, to test therapeutic approaches. We also developed a new codon-edited transfer RNA (tRNA) method for correcting PTCs. Codon-edited tRNAs bind to the target PTC on the mRNA, but are loaded with the correct amino acid, resulting in a full-length wild-type protein. Codon-edited tRNAs have limited interaction with native stop codons. Here, we show that the heterozygous SCN2A R1626X mouse exhibits behaviors associated with SCN2A autism and that our codon-edited tRNA system can rescue PTCs in human and mouse neurons.

Methods:Mice heterozygous for the SCN2A R1626X mutation were generated by the University of Iowa Genome Editing Center. To record ultrasonic vocalizations (USV), pups were separated from their mothers on postnatal day 6 (P6) and recorded for 5 minutes (n=10-15 per genotype). For behavioral work in adult mice, mice aged between 10 and 20 weeks (n = 9–15 per genotype) were tested in open field, novel object exploration, Erasmus ladder, three-chamber social interaction test, and free social interaction in male and female mice were used for all experiments and the results were analyzed by two-way ANOVA or linear mixed models, as appropriate.

For mouse neuronal cultures, the cerebellum was dissected from P6 pups to isolate cerebellar granule neurons (CGNs). Plasmids were transfected or nucleofected (Lonza) into neurons using PolyJet or Mirus reagents. Cells were analyzed by immunofluorescence 96 hours after transfection.

For human neuronal cultures, induced pluripotent stem cells (iPSCs) were generated from a patient with an SCN2A C959X mutation and a neurotypical control. iPSCs differentiated into neuronal progenitors by dual SMAD inhibition and differentiated progenitors into neurons in BrainPhys supplemented medium.

The plasmids in this study contain fluorescent reporters (mOrange2 or eGFP) designed to encode a PTC and codon-edited tRNA to correct the PTC. Plasmids were transfected into human neurons using Lipofectamine STEM transfection reagent. For quantitative PCR, SCN2A expression was quantified using PrimeTime primers (Integrated DNA Technologies) normalized to GAPDH. For Western blotting, cerebellum was dissected from adult SCN2A R1626X mice and WT littermates, then lysed and run on a gradient gel under standard conditions. The NaV1.2 protein was detected using a custom antibody (gift of Dr. Geoff Pitt, Cornell University).

Results:Heterozygous SCN2A R1626X pups had a lower mean frequency and longer USPs compared to siblings from the WT litter (p < 0.01), with no difference in the total number of USPs. SCN2A R1626X heterozygous adult mice were more likely to explore the center of the open field than WT littermates (p < 0.05), with no difference in total distance traveled. The Erasmus ladder test showed that SCN2A R1626X mice showed better adaptation to walking (p < 0.05), a form of motor learning, with no evidence of ataxia. We observed no differences in exploration of new objects or social behavior using the three-chamber social interaction test. SCN2A R1626X mice have decreased NaV1.2 protein in the cerebellum consistent with PTC causing functional haploinsufficiency.

Although human SCN2A C959X neurons contain a PTC, SCN2A mRNA levels in C959X neurons were not lower than in control neurons throughout their in vitro maturation, suggesting that human SCN2A transcripts containing PTCs are not subject to any decay. mediated by significant nonsense. Codon-edited tRNA was able to rescue PTCs in fluorescent reporters in mice and human iPSC-derived neurons, showing that codon-edited tRNA can be expressed in neurons and facilitate PTC rescue.

Conclusions:Heterozygous SCN2A R1626X mice exhibit behaviors consistent with aspects of autism and intellectual disability, some of which can be recognized at a very young age, along with a reduced NaV1.2 protein. Human SCN2A-C959X neurons express SCN2A and, to our knowledge, this is the first study showing that codon-edited tRNA can rescue PTCs in human neurons. These models will be useful for testing codon-edited tRNA therapy approaches. Future directions include moving from plasmids to viral vectors that have greater translation potential and trying to correct endogenous PTCs in these mouse and human models.

Key words:Ion channels, autism spectrum disorder and related syndromes, intellectual disability, behavioral tasks, induced pluripotent stem cells (iPSCs)

Disclosure:Nothing to disclose.

Smriti Iyengar*, Mark Varney, Mark Urban, Elizabeth Dugan, David Budac, Qing Chang, Taleen Hanania, Sarah Woller

NINDS, NIH, Rockville, Maryland, EUA

Background:The NINDS Preclinical Pain Screening Platform (PSPP) was developed as part of the NIH-HEAL initiative to facilitate the identification and development of new non-opioid and non-addictive pain treatments. PSPP provides researchers at academic, industrial, and government institutions worldwide with an efficient and rigorous resource to accelerate the development of new small molecule pain treatments, natural and biological products and devices. These new agents accepted by the program will be profiled to assess their in vivo effects in mice in extensively validated pain models and outcomes, with close attention to pharmacokinetic parameters, understanding the potential for neurological deficits in vivo and risk of in vitro drug abuse as well. in vivo.

Methods:Male and female SD rats (Envigo, Indianapolis, IN) weighing 180-250 µg were acclimatized and housed appropriately for at least one week prior to testing. 12/12 light/dark cycles were maintained throughout the study, with lights on at 6 am. Room temperature was maintained between 20 and 23°C with relative humidity maintained at around 50%. Food (Lab Diet 5001, LabDiet, St. Louis, MO, USA) and water were provided ad libitum during the study. The tests took place during the light phase of the animals between 8:00 am and 5:00 pm. m and 4 pm.

Pharmacokinetic studies were performed to control dosage, select the route of administration and determine the course of time, supporting further behavioral studies. Modified Irwin (n = 4) and Rotarod (n = 10) tests were performed to assess potential neurological, physiological and fine motor effects that may affect outcome measures in pain models. After assessing the side-effect profile, efficacy was evaluated in the plantar incision pain (n = 10) and L5/L6 spinal nerve ligation (SNL; n = 10) models. The plantar incision model is an established model of acute postoperative pain induced by skin and plantar muscle incision (Brennan et al. 1996). The model is characterized by transient tactile allodynia of the hind paw and spontaneous guarding behavior. SNL is a model for peripheral neuropathic pain resulting from chronic nerve compression in which tactile and cold allodynia occurs (Kim & Chung, 1992). All experiments were blinded, including both sexes.

Statistics: Data were analyzed by one-way ANOVA or repeated measures ANOVA using GraphPad Prism (version 9.2.0), followed by post hoc Dunnett or Bonferroni comparisons where appropriate. An effect was considered significant at the p < 0.05 level. Data are presented as the mean and standard error of the mean (s.e.m.). Performance analysis was used to determine group sizes for the different studies.

Results:Evaluation results of duloxetine, celecoxib, and diazepam suggest that the three drugs had different efficacy profiles in pain-related models.

Administration of duloxetine (10, 30, 60, 100 mg/kg po) did not affect rotarod performance in male or female rats at the doses or times tested. In the modified Irwin test, which evaluated similar doses, the 10 µg/kg dose was well tolerated, but animals treated with 100 µg/kg consistently showed reduced posture, locomotor activity and sedation. In both the plantar incision model and the L5/L6 SNL model, duloxetine was tested at 3, 10, 30, 60 mg/kg PO. In the plantar incision model, duloxetine dose of 60 mg/kg significantly reduced mechanical allodynia and protective behavior in male and female rats, with maximum effect after 1 hour, while duloxetine (60 μg/kg) reduced mechanical allodynia in the SNL model significantly reduced allodynia and cold sensitivity to acetone in males and females compared to vehicle-treated animals, with a peak effect occurring between 1 and 2 hours after treatment.

Ongoing studies with celecoxib (3, 10, 30, 100 mg/kg po) indicate that the drug did not affect rotarod performance in male or female rats at the doses or times tested. In the plantar incision model (10, 30, 60 mg/kg PO), celecoxib significantly reduced arousal behavior in men and women at 1, 2, 4, and 6 hours, but did not affect allodynic behavior.

At doses of 1, 3, 10 and 30 mg/kg p.o. Diazepam treatment produced dose-dependent sedative effects, including decreased posture, decreased locomotor activity, ataxia, visual localization after nasal contact, and decreased grip strength in both males and females. and women on the modified Irwin test and significantly impaired rotarod performance in men at 1 hour and in women at 1 and 2 hours after treatment. While diazepam (1, 3, 10 mg/kg PO) showed a statistically significant effect on PWT in male and female rats and on alertness in female rats in the plantar incision model, it did not sustainably alter these behaviors. Administration of diazepam had no effect on PWT or cold sensitivity to acetone in men and women in the L5/L6 SNL model at similar doses for 6 hours post-dose.

Results are presented in the context of pharmacokinetic parameters.

Conclusions:In summary, evaluation of the clinically used drugs duloxetine, celecoxib, and diazepam revealed distinct profiles in the PSPP paradigm consistent with their clinical utility. The NINDS PSPP program aims to accelerate the development of new pain therapies that are non-opioid and non-addictive.

Key words:Pain therapy profiles, clinical pain patterns, pain models

Disclosure:Retirees, Eli Lilly and Company: Other financial or material assistance (self-employed)

Mark Demitrack*, Michael Kramer, Cathy Michalsky, Hemme Hijma, Laurence Moss, Geert Jan Groeneveld

Trevena, Inc., West Chester, Pennsylvania, USA

Background:Olyceridin is an agonist at the mu-opioid receptor with preferential downstream involvement in G-protein signaling, while showing reduced beta-arrestin recruitment and receptor internalization (DeWire, 2013). Opioid medications are an essential part of pain management after surgery, although a variety of opioid-induced adverse events (AEs) complicate their use. Prominent among them is the development or exacerbation of cognitive dysfunction, which can range from sedation to confusion or progression to delirium. Therefore, cognitive dysfunction can have potential implications for postoperative recovery and health outcomes and, in some cases, lead to impairments that persist beyond the immediate postoperative period. The mechanism of these cognitive complications is unclear, although it has been hypothesized that opioids such as morphine may bind to Toll-like receptor 4 (TLR4) and the subsequent neuroinflammatory response may contribute to these postoperative cognitive consequences (Muscat, 2021). 🇧🇷 Rats treated with olyceridine show reduced levels of TLR4 in the spinal cord after an experimental fracture compared to animals treated with morphine (Liang, 2018). The present study was designed to characterize the neurocognitive effects of IV olyceridine versus IV morphine using a set of validated cognitive tests. We hypothesized that IV olyceridine would show a smaller effect on cognitive measures compared to IV morphine.

Methods:Twenty-three healthy subjects (13 men, 10 women; mean age 26 years) gave informed consent and were randomized to receive 3 of 5 possible regimens as single intravenous doses in a partial-block crossover design: placebo, olyceridine 1 mg or 3 mg or morphine 5 mg or 10 mg. The dose range for each drug was selected based on previous data confirming a relative potency of olyceridine to morphine of approximately 1 to 5 and the maximum approved single dose of olyceridine (3 mg; Olinvyk® product label). Neurocognitive function was assessed using the NeuroCart® test battery at: baseline, 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours. The primary outcome of the study was peak saccadic eye movement velocity, a sensitive measure of sedation. Secondary outcome measures included saccadic eye movement reaction time and percent imprecision, smooth eye movement tracking, adaptive eye-hand coordination tracking test, postural stability as measured by body sway, and symbol-digit substitution test. Right and left pupillometry and analgesia, measured with the cold pain test, assessed the adequacy of targeting. Results were examined using a mixed ANOVA model, using treatment, period, time, and treatment after time as fixed factors, subject, subject after treatment, and subject after time as random factors, and mean baseline as covariates. For a significant main treatment effect, pairwise comparisons were made between groups of treatment conditions.

Results:Consistent with the known relative potencies of IV olyceridine and morphine, both drugs exhibited the expected effects on opioid-induced pupillary constriction and analgesia in response to cold pain tests in the dose ranges studied.

There was a statistically significant treatment effect on the primary endpoint of saccadic eye movement velocity (main treatment effect, P <0.0001), driven by a reduced, beneficial effect of oliceridine versus IV morphine (mean treatment per LS [95% CI] : -11.40 deg/s [-21.19, -1.61], P = 0.0236). Similar results in favor of olyceridine were seen for the secondary endpoints of saccadic eye movement reaction time (main treatment effect, P =0.0201; LS mean treatment difference [95% CI]: 0.0088s [0. 0010; 0.0166], P = 0.0273) , reduction in body sway (main treatment effect, P =0.0314; mean difference of LS treatment [95% CI]: 16.1% (mm) [- 2.7%, 38.5%], P = 0.0951) and better performance accuracy in the adaptive tracking test, a measure of hand-eye coordination (main treatment effect, P = 0.0011, mean treatment difference CM [95% CI]: -1.519% [-3.505, 0.467], P = 0.1303).

Additional neurocognitive findings, visual tracking and digit symbol substitution test, showed no statistical difference between olyceridine and IV morphine. No serious adverse events were observed in the study. Common adverse events included expected opioid-related adverse events such as nausea, vomiting, and drowsiness. Events were classified as mild in all cases, with the exception of a mild nausea AE in a morphine-treated subject.

Conclusions:IV olyceridine has less impact than IV morphine on several clinically relevant measures of cognitive performance, including certain measures of sedation, motor performance, and hand-eye coordination.

Key words:Cognition, Opioids, Clinical Psychopharmacology, Postoperative Cognitive Dysfunction

Disclosure:Trevena, Inc.: Employees (own)

Felix Mayer*, Adele Stewart, Michelle Vélez, Maximilian Rabil, James Foster, Roxanne Vaughan, Lynette Daws, Sammanda Ramamoorthy, Randy Blakely

Florida Atlantic University, Jupiter, Florida, USA

Background:The availability of extracellular dopamine (DA) is tightly regulated by the dopamine (DA) transporter (DAT). The rare DAT variant Val559 has been identified in people with Attention Deficit Hyperactivity Disorder (ADHD), Bipolar Disorder and Autistic Spectrum Disorder (ASD). DAT Val559 exhibits abnormal DA efflux (ADE), a feature shared by several disease-associated DAT variants. Mice expressing DAT Val559 show increased extracellular DAT in the striatum and show hyperresponsiveness to imminent handling, waiting impulsivity, working memory deficits, and increased reward motivation. ADE supports ongoing activation of D2-type DA autoreceptors (D2ARs), resulting in increased surface expression and hyperphosphorylation of DAT Val559 in a sex- and circulation-specific manner. Synthesis of dynorphin, the endogenous ligand of kappa opioid receptors (KORs), can be increased postsynaptically by increasing DA signaling at D1 receptors. Enabling KOR, in turn, leads to high DAT surface traffic on DA end devices. Consequently, we hypothesize that antagonism of KORs by reducing dynorphin signaling may reduce surface levels of DAT Val559, which are prone to leakage, and thus suppress neurochemical and behavioral phenotypes in DAT Val559-KI mice.

Methods:We performed biotinylation and surface immunopurification assays using sharp coronal sections containing the dorsal and/or ventral striatum of DAT Val559 and wild-type (WT) mice to assess the effect of KOR agonist U69,593 and KOR antagonist on rate. norBNI) on surface expression and phosphorylation of WT DAT and DAT Val559 ex vivo. To measure the effect of systemic norBNI (10 mg/kg, i.p.) on DA release in vivo, we performed microdialysis and fiber photometry, the latter effort using genetically encoded and virus-expressed sensors for AD. After administration of vehicle or norBNI (10 mg/kg, i.p.), mice expressing Val559 WT and DAT were tested in the Y-maze and field test. All mouse experiments were performed according to a protocol approved by the Florida Atlantic University Institutional Animal Care and Use Committee (IACUC).

Results:Using sharp sections of DAT Val559 and WT mice, we found that DAT Val559 remains amenable to regulation via KOR. Regardless of genotype, exposure to U69,593 increased surface DAT expression, which was accompanied by DAT phosphorylation of threonine 53 (Thr53). In contrast, challenge with norBNI normalized the increase in basal surface expression of DAT Val559 and hyperphosphorylation at Thr53, but had no effect on WT DAT. Assessment of DA dynamics in DAT Val559 in vivo compared to WT revealed that systemic norBNI normalized vesicular release of DA in the dorsal striatum of male mice. Finally, norBNI was found to restore alternating deficits (Y-maze) and anxiety-related behaviors (decreased open-center-field time) observed in DAT Val559 mice.

Conclusions:DAT-Val559-mediated ADE occurs independently of neuronal activity and results in tonic activation of D2ARs, supporting a feedback loop that recruits additional efflux-prone transporters to the plasma membrane. By targeting KOR, a well-established regulator of neuronal DAT activity and surface DAT expression, we identified KOR antagonism as a promising strategy to improve neurochemical and behavioral phenotypes arising from disease-associated variant DAT expression. More generally, our observation that KOR antagonism in WT animals had no serious implications for the measurements obtained supports KOR antagonism as a potentially useful strategy to compensate for biochemical and behavioral deficits associated with hyperdopaminergic states.

Key words:Dopamine Transporter, ADHD, Opioid Kappa Receptor, TEA, Dopamine

Disclosure:Nothing to disclose.

Michael Kramer*, Ruihua Chen, Mark Demitrack

Trevena, Inc., Chesterbrook, Pennsylvania, USA

Background:Epilepsy is caused by abnormal synchronized firing of neurons resulting from an imbalance in excitatory and inhibitory neurotransmission. The main antiepileptic drugs (AEDs) are direct modulators of ion channels, but they do not control seizures in 30% of patients. There is a need to discover and develop AEDs with new mechanisms to treat refractory epilepsy.

S1P and its receptors, particularly subtype 1 (S1PR1), play an important role in neuroinflammation, a process that underlies seizures and epileptogenesis. S1P receptor expression is increased in experimental TLE mouse models after status epilepticus (SE). Fingolimod, a non-selective but highly potent S1PR1 modulator, has demonstrated antiepileptic effects in a variety of preclinical epilepsy models, possibly through anti-inflammatory mechanisms and preservation of blood-brain and neuronal barrier integrity. However, non-selective S1PR modulators such as fingolimod cause lymphopenia.

TRV045 is a highly selective S1PR1 modulator that does not cause lymphopenia in animal models. Through collaboration with the NINDS Epilepsy Therapy Screening Program (ETSP), we have previously shown that subcutaneous dosing of TRV045 reduced seizures in the mouse corneal activation (CK) model and the mouse maximal electric shock (MES) seizure model. , but other models have used here a new vehicle (10% Cremophor, 20% Captisol in water) for oral (PO) dosing of mouse CK, mouse MES, Theiler murine encephalomyelitis virus (TMEV) and kainic acid in seizures post-spontaneous recurrent seizures using (KA-SRS) mouse model of temporal lobe epilepsy.

Methods:In the MES model, male Sprague Dawley (SD) rats were fed with 60 Hz alternating current of 150 mA for 0.2 s through corneal electrodes. Rats (n = 8/gp) were dosed PO with 30 or 60 mg/kg of TRV045 and analyzed for seizure activity 0.25 to 2 hours post dose to identify time to peak effect (TPE) . An animal was considered "protected" from seizure activity when the tonic hindlimb stretch component of the seizure ceased. A complete dose response was then achieved with testing on the TPE.

In the CK seizure model, male C57BL/6 mice were fully activated to meet criteria for 5 consecutive stage 5 seizures. Mice (n = 8/gp) were dosed 5-7 days after the last PO challenge with 10 or 15 mg /kg of TRV045 and tested for TPE at 1 and 2 hours post-dose. A complete dose response was then performed by testing the TPE to identify an ED50 dose.

In the TMEV model, male C57BL/6J mice (n=18-20/gp) were pretreated with TRV045 for 2 days (10 or 30 mg/kg, b.i.d., PO) and then challenged with TMEV on day 3. Daily continued assessment of seizure severity using a modified Racine scale until day 7.

In the KA-SRS model, status epilepticus was induced in male SD rats by repeated treatment with low doses of kainate. After a 7-day baseline period, rats (n=6/gp) received intraperitoneal (IP) doses of TRV045 or vehicle for 5 days. After a 2-day washout period, animals were transferred to the other treatment arm for a second 5-day washout period. Seizure burden was calculated as the sum of all seizures in the Racine scale format during treatment divided by the number of days of treatment. Seizure-free was based on a seizure-free animal from the time of the first dose to 12 hours after the last dose.

Results:TRV045 prevented seizures in the MES mouse model of generalized tonic-clonic seizures with a TPE from 0.5 to 1 hour post-dose. Tested 0.5 hours post dose, oral doses of 20, 30, 40, 50 and 60 mg/kg of TRV045 prevented generalized seizures in 1, 4, 3, 1 and 0 of 8 rats, respectively. Tested 1 hour after administration, PO doses of 3, 10, 20, and 40 mg/kg of TRV045 prevented generalized seizures in 0, 3, 2, and 0 of 8 rats, respectively. No ED50 was identified due to the inverted U-shaped dose-response curve.

TRV045 protected mice from secondary chronic generalized focal seizures in the CK mouse model. In the initial time course evaluation, 10 mg/kg of TRV045 PO protected 5 of 8 mice at 1 and 2 hours post dose, while 15 mg/kg protected 6 of 8 mice at 1 hour and 4 of 8 mice at 2 hours. Hours after ingestion, with a mean seizure score of 1.25 to 2.5. In the complete dose-response study with TPE testing 1 hour post-dose, 1, 2.5, 10, 15 and 20 mg/kg of TRV045 PO protected 0, 4, 5, 6 and 6 of 8 animals, respectively. TRV045 produced a dose-dependent effect on seizure scores ranging from 2.5 (2.5 mg/kg) to 1.25 (20 mg/kg), resulting in a calculated ED50 of 5.97 ± 0.47 mg/kg. kg driven.

TRV045 did not significantly reduce the cumulative seizure burden in the TMEV model. The cumulative seizure burden was 88 ± 10% of vehicle in the 30 mg/kg group, with no effect on the absence of seizures. Cumulative exposure to seizures was 90 ± 18% of vehicle in the 10 mg/kg group, with a non-significant increase in the absence of seizures (7/20 versus 4/20 in the vehicle group).

In the KA-SRS model, TRV045 IP 10 mg/kg significantly reduced mean seizure burden compared to baseline (3.1 ± 0.9 vs. 13.4 ± 6.6; p < 0.05 Wilcoxon rank sum), improved, but not significantly, freedom from seizures (3 out of 12 protected ). versus 2 of 12 vehicle-treated). A dose of 15 mg/kg significantly reduced mean seizure burden compared to vehicle (5.0 ± 4.0 vs. 9.0 ± 2.7; p<0.05) and significantly improved seizure absence (6 of 12 protected vs. 1 of 12 vehicle treated). ;p < 0.05 Fisher's exact test).

Conclusions:The S1PR1 modulator TRV045 prevented generalized seizures in the MES mouse and rat CK models and reduced seizures in the KA-SRS chronic spontaneous seizures model, suggesting that it is a viable candidate for human investigations in the treatment of CKD epilepsy.

Key words:Epilepsy, S1P Receptor, Seizures, Preclinical Pharmacology, Pharmacotherapy

Disclosure:Trevena, Inc.: Employees (own)

Pietro Scaduto, William Russell, Agenor Limón*

University of Texas at Galveston Medical Department, Galveston, Texas, USA

Background:People in various stages of Alzheimer's disease (AD) exhibit abnormal electroencephalographic activity, which has been linked to network hyperexcitability and cognitive impairment. However, it is unclear whether pro-excitatory changes at the synaptic level in the affected brain areas are observed in early AD and whether they occur in mild cognitive impairment (MCI). Equally important, it is unknown whether global synaptic E/I imbalances correlate with the severity of cognitive impairment in AD.

Methods:Using electrophysiology and proteomics of synapses in the human hippocampus and temporal cortex, people with mild cognitive impairment (MCI) and AD, we aimed to determine global synaptic balance in the hippocampus and temporal cortex at different stages of neuropathology. Electrophysiological synaptic E/I ratios in post mortem samples from the temporal cortex of individuals with MCI (n=6) or AD (n=6) compared to controls without dementia (n=6) and from the hippocampus (MCI, n=8; AD n = 11, CTRL = 8) were evaluated by synaptic membrane microtransplantation (MSM). The proteomics of temporal cortex synaptosomes was analyzed in the context of their electrophysiological responses by analyzing anchored electrophysiological datasets (EDA).

Results:We found that the greater the amplitude of GABA receptor currents, the better the assessment of cognitive performance. A similar association was observed for AMPAR currents. The electrophysiological E/I ratio was significantly higher in the CTx of patients with AD and was negatively associated with the MMSE in the TCx, but not in the hippocampus. The synaptoproteome revealed the impact and direction of protein changes and neuropathology on the amplitude of synaptic receptor responses and MMSE cognitive scores. Using electrophysiologically anchored analyzes of the synaptoproteome in the same individuals, we identified a group of proteins that support synaptic function and those implicated in synaptic toxicity. We also found a discrepancy between function and protein expression for GABAergic signaling in the temporal cortex, underlying higher E/I and worse cognitive performance in this region.

Conclusions:These results indicate that early changes in E/A balance contribute to cognitive decline across the continuum of AD symptoms.

Key words:Excitatory inhibitory balance, Alzheimer's disease, postmortem brain tissue, excitatory synapses, inhibitory synaptic transmission

Disclosure:Nothing to disclose.

Lara Boyle*, Lorenzo Posani, Sarah Irfan, Steven Siegelbaum, Stefano Fusi

Columbia University, New York, New York, United States

Background:Memory is the basis of all complex social relationships. The hippocampus is important for remembering interactions and information about other people; in other words, it is essential for social recognition memory. Social memory consists of two interrelated processes: the general sense of whether and to what extent one has known another person before (familiarity) and the specific recall of details or episodes concerning another person (memory). So far, the neural mechanisms underlying familiarity and recall are unclear, even though familiarity and recall depend on the same brain region. Previous studies in rodents have shown that the CA2 subregion of the hippocampus is of particular importance for social memory, as assessed through social novelty recognition. However, it is unknown how familiarity and identity encoding are represented in CA2 and how they relate to other variables known to be encoded in the hippocampus (space, time). Here we examine the neural mechanisms of familiarity and identity encoding within the CA2 hippocampus, including the consequences of different neural representation models for memory.

Methods:We injected a Cre-dependent virus into the dorsal CA2 region (dCA2) of male Amigo2-Cre mice to selectively express the genetically encoded calcium reporter GCaMP6f in dCA2 pyramidal neurons. We implanted a smile lens into CA2 to measure calcium events in large numbers of dCA2 pyramidal neurons in awake animals. We recorded behavioral images of mice exposed to different combinations and locations of novel and familiar individuals to study changes in neuronal activity during experiments with different combinations of familiarity, identity, position and time. These combinations included: new and familiar individuals in two position-switch trials (same identity in all trials, n = 12), new and familiar individuals in two position-switch trials (different identity in all trials, n = 5 ), two new individuals (n = 11) and two family members (n = 11). We characterize population maps of CA2 neurons using a decoding approach (linear support vector machine). In each case, we used data from the two studies to determine the extent to which social, spatial, and study information could be deciphered. We then use a technique called Cross Condition Generalization Performance, which provides information about how variables in the neural code interact (the dimensionality of these representations) to explain the relationship (the degree of entanglement) between different variables (familiarity , identity, space). 🇧🇷 determine , and time) in the neural code.

Results:We found that the familiarity of interaction partners and their locations can be decoded from the activity of the dCA2 population (social decoding performance = 0.88; probability = 0.49 ± 0.02, p < 0.001; spatial decoding performance = 0.90; probability = 0.51,0.02; p < 0.001). Trial decoding was inferior to social or spatial decoding (trial decoding performance = 0.62; probability = 0.54 ± 0.02; p < 0.001). Test decoding also indicates the dimensionality of social and spatial coding, with low test decoding indicating low dimensionality and high test decoding supporting high dimensionality. We calculated cross-condition generalization performance (CCGP), another dimensionality marker. The CCGP is inversely proportional to the dimensionality of the represented variables. We found that familiarity and spatial CCGP were significantly greater than chance (CCGP = 0.77, probability level = 0.51 ± 0.03 (mean ± SD); p < 0.001; spatial CCGP = 0.76; probability level = 0.49 ± 0.03, p0.03 ). We then looked at CCGP and tested decoding for both new and familiar people. We found that new people were represented with low dimensionality but high CCGP and low test decoding (new identity CCGP =0.77; chance =0.50±0.04; p<0.001; test decoding = 0.62; chance = 0.49 ± 2, p0.00 0 1 ), family members were represented in higher dimensions, with relatively low CCGP and high decoding judgment (Family Identity CCGP = 0.62; chance = 0.50 ± 0, 04; p < 0.001; judgment decoding = 0.69; chance = 0.50 0.03 0; p < 0.001; p < 0.001; <1)0. 🇧🇷 We build a geometric model that recapitulates these experimental results. Furthermore, we develop a theoretical argument that captures the benefits of higher-dimensional representations for fictitious memory.

Conclusions:Our experiments and analyzes show that dCA2 encodes both social familiarity and social identity in individuals with a similar degree of novelty or familiarity, the latter being a key requirement for harvesting. We found that familiarity is encoded in a low-dimensional space, which means that this information as a variable is not tied to other variables (identity, space, time). Likewise, while new identities are encoded in a lower-dimensional structure, familiar identities are encoded in higher-dimensional representations, which means that identity, space, and time variables are intertwined. The different geometric arrangements of familiar and novel representations of animals provide a neural mechanism that allows the brain to quickly distinguish between social familiarity and social novelty while storing detailed information from social experiences with familiar animals, allowing the same brain structure to encode the two main components of social recognition memory: social familiarity and social memory.

Key words:Dorsal hippocampus, social recognition memory, recall and familiarity

Disclosure:Nothing to disclose.

Moriah McGuier, Crystal Noller, Diana Wallin, Lucas Dwiel, Emily Sullivan, Patrick McCunn, Katelyn Salotto, Armando Braz, John Kanter, Krista DiSano, Paul Holtzheimer, Wilder Doucette*

Geisel School of Medicine, Lebanon, New Hampshire, USA

Background:A traumatic brain injury (TBI) affects nearly 69 million people worldwide. Military personnel are at high risk for traumatic brain injuries, particularly blast injuries (bTBI), due to proximity to explosive devices. bTBI increases the risk of developing post-traumatic stress disorder, mood and anxiety disorders, and substance use disorders. Current psychotherapeutic and pharmacological treatments for these psychiatric sequelae provide some symptom relief but fail to address the underlying neural dysfunction. Using preclinical models will allow us to identify the neural correlates of onset and relate these biomarkers to emerging post-onset behavioral phenotypes. With this understanding, we hope to guide the implementation of new interventions (eg, brain stimulation) to promote recovery from the chronic neuropsychiatric sequelae of bTBI. We hypothesize that bTBI-induced disruption of communication in the striatal-frontal limbic system (using translationally relevant measures [eg, MRI and electrophysiology]) will identify biomarkers of blast injury that correlate with behavioral phenotypes.

Methods:Fifty-five male Sprague-Dawley rats underwent hyperbaric burst injury using a rupture tube (ORA, Inc) or were naïve controls. We evaluated blast parameters, including varying overpressure targets and interblast intervals, until significant changes in delay discount task performance were observed (n = 15). We then use these parameters (three events∼126 kPa [18 psi] with an interval between bursts [IBI] of ~3 min) in a large cohort (n = 40) and evaluated a variety of behaviors starting one month after the explosion: 1) field test with automatic evaluation of the behavior; 2) preference for sucrose; 3) Morris Water Maze (MWM) and 4) contextual fear conditioning. After behavioral assessment, a subset of rats (12 bTBI and 12 controls) were implanted with electrode arrays targeted to the bilateral infralimbic cortex, orbitofrontal cortex, nucleus accumbens (NAc) and NAc layer for LFP recording. We quantified 216 LFP properties (power and coherence) over 6 specified frequency ranges (delta to high-end) and used machine learning to determine whether the explosion and control LFP data could be classified more accurately than the datasets exchanged. The permutation and relearning features importance test was then used to identify the most important LFP features. Another subgroup (8 bTBI and 8 controls) underwent magnetic resonance imaging for functional analysis at rest (rs-fc) and diffusion tensor imaging (DTI). We used seed-based analyzes (anterior medial and NAc) to determine whether there were significant connectivity differences between groups (blast vs. control) and region-of-interest analyzes that matched our electrode positions for DTI metrics (eg, . diffusivity average) to [MD]).

Results:We found that none of the rats in the 24-hour IBI group showed significant changes in DDT performance from pre-burst to post-burst, whereas about half of the rats in the 3-minute IBI group showed significant changes, making more impulsive decisions (t-test paired p <0.05) after the explosion. No fear-related or movement-related differences were found using open-field metrics, but automated behavioral assessment revealed significantly less grooming in mistreated rats (unpaired t-test p = 0.0035). Blast-damaged rats showed a greater preference for sucrose (2-way ANOVA p = 0.0182) than control rats. We found no difference between groups in mean latency to the platform on training days (p = 0.1243) for MWM. After conditioning to an aversive paw shock, no differences were observed between groups during the 3-minute post-shock interval (p = 0.5106), but blast-injured rats showed significantly more freezing (2-way ANOVA p = 0.0458) when they returned to the 24-hour conditional context. later. Machine learning models showed that LFP traits can classify animals as burst versus control with average model performance (area under receiver-operator characteristic curve [AUROC] = 0.7656), yielding p = 0.0348 in comparison with the permuted distribution. Feature importance tests showed reduced low and high gamma power in frontal regions compared to controls. Analyzes of Rs-fc and DTI revealed a number of structural and functional differences between blast-injured animals and control animals. For example, rs-fc analysis showed that NAc-seed had decreased connectivity with frontal regions, and DTI analysis suggested (p = 0.02) decreased MD in frontal brain regions of blast-injured animals.

Conclusions:Our data are consistent with published work showing that blast injuries in rodents are associated with a variety of neurobehavioral outcomes, including increased impulsivity and anxiety. Importantly, we found distinct neural signatures in injured animals that correlate with observed behavioral deficits, supporting a potential role for neural biomarkers in guiding rehabilitation after injury. Future work will determine how these biomarkers predict recovery and response to treatment, including focal brain stimulation.

Key words:Traumatic brain injury, neural oscillations, functional and structural MRI, delay discount, contextual anxiety

Disclosure:Nothing to disclose.

Seung Woo Kang*

Augusta University of Georgia School of Medicine, Augusta, Georgia, USA

Background:Social behavior is essential for animals to maintain healthy lifestyles. Consequently, impaired or dysfunctional social behaviors are correlated with various psychiatric and neurological disorders. The paraventricular nucleus of the thalamus (PVT) is believed to be the central area of ​​the brain that controls contextual emphasis and aversion processing, including social behaviors. Indeed, recent studies suggest that PVT displays a variety of neural signals depending on social status and that activities are significantly correlated with social behavior.

Accumulating evidence shows that astrocytes not only play the role of microstructural support in neural circuits, but also physically form tripartite synapses with neighboring neurons and directly modulate neuronal activities through the release of gliotransmitters or the uptake of overloaded neurotransmitters. However, the coordinated activities of astrocytes and neurons in coding PVT for social behavior remain unknown.

Methods:To study astrocyte activity-induced changes in neighboring neuronal activity and behavioral consequences, we chemogenetically activated astrocytes in the PVT using GFAP promoter-driven expression of hM3Dq, the excitatory drug-activated receptor (DREADD) design. First, we used ex vivo and in vivo calcium imaging to study chemogenetically induced cellular activity in mouse PVT astrocytes expressing the calcium fluorescence reporter GFAP-GCaMP6s. Next, we recorded electrophysiological changes in activation and synaptic activity of PVT neurons. To assess behavioral consequences, we subjected mice to three-chamber social focus tasks. Mice were exposed to the camera in three different social conditions: without social factors for habituation and location preference determination, with an unknown mouse, or with an unknown mouse and a familiar mouse. Social preference was measured as a comparison between the time the subject spent with a strange rat and a new object (sociability) or a familiar rat (social approval).

Results:Chemogenetic activation of PVT astrocytes increased the intensity and frequency of calcium signaling. Interestingly, astrocyte activation increased firing and elicited excitatory postsynaptic currents (eEPSCs) in PVT neurons. Alterations induced by astrocytic activation in eEPSCs were significantly inhibited by astrocyte-specific knockdown of a glutamate transporter, GLT1 (known as EAAT2, slc1a2), by expression of .GFAP promoter-driven Cre recombinase in GLT1-flogged mouse PVT. Changes in eEPSC were also obscured by pretreatment with DHK, a specific GLT1 blocker, suggesting that GLT1 is at least partially required for astrocyte-induced changes in neuronal activity in PVT. When assessing social behavior, we found that astrocyte activation significantly reduced social recognition in the three-chamber social focus test. Importantly, mice lacking GLT1 selectively in PVT astrocytes mimicked the impairment in social behavior induced by astrocyte activation.

Conclusions:Taken together, our observation indicates that astrocyte activity in the PVT modulates neighboring neuronal synaptic events not only through passive homeostatic activities, but also through direct modulation of glutamatergic signaling, at least in part, by GLT1, resulting in modulation of social behavior. This implies the importance of astrocytes as another layer to modulate social behavior and the interaction between astrocytes and neurons through glutamatergic signaling could be a potential therapeutic target for related diseases.

Key words:Social behavior, astrocytes, glutamate transporters, paraventricular nucleus of the thalamus

Disclosure:Nothing to disclose.

Peter van Roessel*, Sepehr Asgari, Booil Jo, Leanne Williams, Carolyn Rodriguez

Stanford University School of Medicine, Stanford, California, USA

Background:Obsessive Compulsive Disorder (OCD) is a common and debilitating illness. First-line pharmacological treatment with selective serotonin reuptake inhibitors helps most patients, but benefits can take weeks to materialize and many patients do not achieve an adequate response. Ketamine and other glutamatergic interventions show promise as alternative and faster-acting treatments. However, the growing variety of treatment options increases the need for data to support the goals of precision medicine and finding the right treatment for the right patient.

OCD has been associated with disturbances in cognitive and affective processing, as assessed by neuroimaging and behavioral tests. These changes include deficits in cognitive control and a valence bias reflected in increased threat response and decreased reward response. In a secondary analysis of data from a randomized, active placebo-controlled trial of intravenous ketamine for the treatment of OCD, we examined whether validated behavioral measures of cognitive control and valence processing are useful as predictive biomarkers or clinically meaningful treatment targets.

Methods:We analyzed data from N = 45 DSM-5 OCD treatment-naive subjects who participated in a randomized controlled trial investigating the mechanisms of ketamine as a short-acting treatment. Participants were randomized 2:1 to receive a single intravenous infusion of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) over 40 minutes. Clinical symptoms of OCD were assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) at baseline, day 1 post-infusion, and day 7 post-infusion. In addition, participants completed a validated battery of computerized neurocognitive tests ("WebNeuro") one day before and one day after the infusion. Tests included measures of cognitive control (performance on Stroop color word interference and go/fail tests) and valence processing (performance on emotion identification and implicit priming tests with facial expressions of fear and happiness), quantified as z-scores for age, gender, and years of training in compliance with healthy standards. We examined whether baseline performance on tests of cognitive control and valence processing moderates symptom relief in response to ketamine versus midazolam, and whether a change in test performance before and after test performance is associated with symptom relief. MacArthur's criteria were used to define possible moderating and mediating variables.

Results:Treatment had a significant effect on OCD symptoms on day 1 (β=-7.894, p=0.004, corresponding to a mean difference of almost 8 points in Y-BOCS change for ketamine versus midazolam) and on day 7 (β = -6.048, p=0.005). In moderation analyses, the interaction between a measure of Stroop reaction rate interference and treatment had a significant effect on the change in Y-BOCS on day 1 (β = -4.0618, Cohen's f2 = 0.14, p = 0.04), but not on day 7. That is, the treatment effect on day 1 was significantly greater for those with faster normalized performance on a color naming task compared with color word reading. Performance on the go/no-go tests and valence processing did not moderate the effect of treatment on Day 1 or Day 7 outcomes. In mediation analyses, treatment had no significant effect on earlier or later changes in cognitive control or processing valence; these measures did not meet the criteria as potential mediators of Y-BOCS changes. However, the pre-post change in Stroop interference by reaction rate was correlated with the change in Y-BOCS on day 1 (r = 0.36, p = 0.03).

Conclusions:Ketamine significantly reduced OCD symptoms on day 1 and day 7 post-infusion compared with active placebo midazolam. Our data suggest that the short-term effect of ketamine versus midazolam on Y-BOCS may be affected by early inhibitory cognitive control, such that greater control (less Stroop interference for color naming) predicted a greater benefit of ketamine versus midazolam . Our data may be consistent with published findings suggesting that Stroop task performance moderates the effectiveness of other OCD treatment modalities (eg, cognitive-behavioral therapy versus fluoxetine).

Key words:OCD, Ketamine, Neurocognitive Assessment, Moderators, RCTs

Disclosure:Nothing to disclose.

Carolyn Rodriguez*, Chi-Ming Chen, Gary Glover, Booil Jo, Daniel Spielman, Leanne Williams, Peter van Roessel, Charles DeBattista, Pamela Flood, Alan Ringold, Max Wintermark, Kelley Anderson, Omer Linkovski, Anthony Lombardi, Andrea Millen, Anthony Pinto, Hannah Raila, Keara Valentine, Maria Filippou-Frye, Jessica Hawkins, Elizabeth McCarthy, Pavithra Mukunda, Andrea Varias, Jordan Wilson, Brianna Wright

Stanford University, Stanford, California, USA

Background:The development of new, robust treatments for obsessive-compulsive disorder (OCD) is an urgent public health need because obsessive-compulsive disorder often begins in childhood, leads to lifelong morbidity, and costs the economy $2.1 billion (direct costs) and US$6.2 billion (indirect costs such as lost productivity). ) annually. Obsessive-compulsive disorder is characterized by an inability to suppress intrusive thoughts (obsessions) and repetitive behaviors (compulsions). Treatment of OCD with serotonin reuptake inhibitors (SSRIs) has a long lead time (2 to 3 months) before clinical benefit occurs, and these benefits are usually only partial. Identifying effective, fast-acting treatments will help reduce the morbidity of OCD and its impact on life. We previously reported the rapid reduction in OCD symptoms with ketamine, a glutamate-N-methyl-D-aspartate (NMDA) receptor antagonist, compared with saline infusion in a proof-of-concept crossover study (n = 15) in untreated adults with OCD. Based on this initial finding, we evaluated the efficacy of ketamine in a larger group of unmedicated obsessive-compulsive patients with better control conditions (active placebo control condition).

Methods:This was a randomized controlled trial of a single ketamine infusion versus an active placebo condition (midazolam, an anesthetic). With institutional review board approval, treatment-naive adult patients (18 to 65 years) with OCD were randomized, under double-blind conditions, to a single intravenous infusion of ketamine (0.5 mg/kg) or midazolam (0.045 mg/kg) in a 2:1 ratio (total n = 45). Participants met DSM-5 criteria for obsessive-compulsive disorder with at least moderate symptoms (Yale-Brown Obsession Compulsive Rating Scale of at least 16). Exclusion criteria included major depression (the 17-point Hamilton Depression Rating Scale was 18 or less at baseline) and psychiatric comorbidities or medical conditions that made participation unsafe. The primary endpoint was change in OCD severity 1 week after drug administration as assessed by Y-BOCS. Duration of action was evaluated with weekly Y-BOCS up to 4 weeks after infusion. We focused on estimating intention-to-treat effects based on longitudinal mixed-effects models. For moderator and mediator research, we apply MacArthur's integrated approach to mixed-effects modeling.

Results:With regard to the primary endpoint, the ketamine group had a significantly greater improvement in the Y-BOCS score than the midazolam group 1 week after treatment (Cohen's d  = 1.25, p < 0.001). The effect of a single intravenous infusion of ketamine persists for up to 3 weeks after the infusion (Cohen's d = 0.59, p = 0.007), gradually decreases with each week and becomes insignificant by week 4. We examined age, sex and ethnicity as potential factors. Moderators of treatment effects, although none were identified as significant moderators. We also examined change in dissociation as a potential mediator of treatment effect, although this was not shown to be a significant mediator.

Conclusions:To our knowledge, this is the largest clinical trial of ketamine in patients with non-medicated OCD to date. Ketamine demonstrated rapid and lasting improvement in OCD symptoms compared to the active control condition. By using an active placebo design optimized to control for non-specific anesthetic effects, this study provides new supporting evidence for the specific therapeutic effects of ketamine in OCD.

Key words:Ketamine, OCD, Midazolam

Disclosure:American Psychiatric Association Publication: Other Financial or Material Support (Agency), Biohaven Pharmaceuticals, Osmind: Consultant (Agency), Biohaven Pharmaceuticals: Contracted Research (Agency)

Brittany Chamberlain*, Matthew Geramita, Susanne Ahmari

University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Background:Obsessive Compulsive Disorder (OCD) is a severe chronic psychiatric disorder characterized by obsessions (recurrent intrusive thoughts and images) and compulsions (repetitive behaviors performed to relieve the anxiety associated with the obsessions). Theories of obsessive-compulsive disorder based on negative reinforcement suggest that the onset and maintenance of compulsions may be driven by this temporary alleviation of obsession-induced anxiety. A recent clinical study by our group (Panny et al., under review, Biological Psychiatry) found increased activity in the medial orbitofrontal cortex (mOFC) when patients with OCD removed OCD images in a new enhancement paradigm. To further analyze the cellular responses that contribute to these massive regional changes in mOFC activity, in this exploratory study we measured neuronal activity using single-photon calcium imaging in wild-type mice during a negative reinforcement task.

Methods:C57Bl6/J mice (n=6; 4 males, 2 females) were trained in a new negative reinforcement task. During the task, a slight signal predicted a footshock, and the mice could avoid shocks with 100% probability by pressing a lever within 20 seconds of the signal ("avoidance response"). If the mice did not press the lever during the signaling period, a series of shocks began. Mice could escape the remaining paw strikes by pressing the lever during that time ("Escape response"). Rats performed 50 trials per day for 7 days. This was followed by 5 days of probabilistic response reinforcement, where pressing the bar resulted in shock avoidance in 50% of trials. Prior to training, mice were injected with virus encoding GCaMP6f (AAV5-CaMKII-GCaMP6f-WPRE-SV40, titer 2.2 × 10^12) in mOFC and implanted with gradient index lenses (GRIN) to study the activity mOFC Use of miniature microscopes (Inscopix) . Single-cell calcium activity was extracted using the CNMF-e algorithm, converted to ∆F/F, and time-limited (i.e., avoidance signal presentation, lever out, lever press, discharge onset) at various time points within each experience. Calcium transients consistent with behavioral events of interest that exceeded >1 standard deviation from the null distribution were considered significant.

Results:Mice quickly learned to avoid paw strikes and showed significantly more avoidance responses (59.3%) than escape responses (29.3%) or failed attempts (11.3%) from the first day of training ( avoidance vs. escape: p < 0.05; avoidance vs. failure: p < .005). On the seventh day of training, the mice avoided 99.8% of potential shocks and showed an avoidance response in 97.3% of attempts. Calcium imaging on the first day of training showed that 13.3% of neurons (69/518) fired at the onset of bar pressing to initiate an avoidance response; This effect persisted over time, with 15.3% of neurons (107/699) firing at the onset of avoidance responses on day 7. Ongoing analyzes of cells tracked over days will determine whether the activity of individual mOFC neurons changes as 1) avoidance behavior improves - learned and maintained over time and 2) after switching from deterministic to probabilistic negative reinforcement.

Conclusions:In OCD, compulsive behaviors are reinforced by temporary relief from anxiety caused by intrusive thoughts and images. Preliminary results from our laboratory indicate that OCD patients exhibit increased mOFC activity in response to removal of OCD-related images, suggesting that this may be a key site of negative reinforcement in OCD. Here we developed a new task that leads to the rapid detection of active avoidance responses in mice and combined it with single-photon in vivo calcium imaging in mOFCs. Preliminary analyzes indicate that a subset of neurons in the mOFC respond selectively while engaging in active avoidance behavior. Further analyzes will determine how mOFC responses are modulated during negative reinforcement training and after changes in task contingencies.

Key words:Active avoidance, negative reinforcement, medial orbitofrontal cortex, obsessive-compulsive disorder (OCD), in vivo calcium imaging

Disclosure:Nothing to disclose.

Matilde Vaghi*, Sunjae Shim, Jaime Ali Rios, Patrick Bissett, Pavithra Mukunda, Carolyn Rodriguez, Russell Poldrack

Stanford University, Stanford, California, USA

Background:One of the obstacles to translating imaging research findings into biomarkers into clinical practice is the shortcomings of traditional approaches. These usually involve analyzing limited data from each subject. Consequently, conclusions are based on cross-subject averages that may obscure individually specific patterns of brain organization. Furthermore, by focusing on a single point in time, the understanding of whether observed effects are stable over time or state-dependent is limited.

Here we use a recently pioneered "dense sampling" scan acquisition, which collects image data on the same subject repeatedly over time, resulting in more data per person. This experimental design allows inferences to be made at the individual level and to capture brain fluctuations on the average timescale of weeks to months that may be relevant to symptom fluctuations. We examined the magnitude and anatomical distributions of intersubject and session network variability in seven high-quality obsessive-compulsive disorder (OCD) patients. Image data were collected while subjects performed cognitive tasks and during rest, but the results presented here refer only to rest.

Methods:Data were collected from 7 patients diagnosed with OCD (4 men; ages: 22-48). For each subject, data were collected over 10 sessions, each on a separate day approximately one week apart. To minimize within-subject variability due to external factors, scans were performed at fixed times of the day, with infrequent variations due to limitations in participant or scanner scheduling. Each session included a psychiatric assessment and an fMRI. Overall, this resulted in approximately 6 hours (3 hours resting) of functional imaging per subject. Magnetic resonance data were acquired on a dedicated GE 3 T research MR scanner with a 32-channel head coil. All functional imaging scans were performed using a multiband, multiecho, and gradient echo EPI sequence. In addition, a T1 and T2 weighted image was created for each subject. Image data was pre-processed with fMRIPrep 22.0.0 and stripped with Tedana. Functional connectivity (FC) was measured by time series correlations between compartmentalized cortical regions using Yeo's 17-grid model. Consequently, an FC connectivity matrix was created for each topic and session. Effects were calculated per subject and compared using two-tailed paired t-tests, with FDR p-values ​​corrected for the number of comparisons.

Results:Individual and group effects on network similarity were examined by calculating correlations between FC connectivity matrices. To quantify group effects, correlations between HR connectivity matrices from different subjects and sessions were examined. This analysis indicated a common basic structure, as the functional networks of different people and sessions showed considerable similarities (mean Spearman correlation  = 0.76). However, networks from the same person and from different sessions were even more similar, with an additional effect of the mean Spearman correlation  = 0.86 on the group effect, showing a strong influence of individual identity on functional networks. We also examined within-subject variability between sessions by calculating, for each subject, the standard deviation of the correlation between each pair of graphs over the 10 sessions. Mean variability across all correlations showed a relatively greater pattern of variability in the visual, somatomotor, and dorsal attentional regions, consistent with analogous studies in healthy subjects. However, unlike studies in healthy subjects, the variability in these networks was not significantly different from that observed in areas of executive control traditionally associated with OCD.

Conclusions:We found that, in patients with OCD, functional networks are dominated by shared organizational principles as well as distinct individual characteristics. These results echo previous research in healthy individuals and extend to patients with OCD, highlighting the importance of individualized approaches to studying features of brain organization. Contrary to previous reports in healthy subjects, the variability in the processing and executive control regions was similar, setting the stage for linking the longitudinal dynamics of brain functions to the variability of psychiatric and behavioral symptoms.

Key words:Obsessive Compulsive Disorder (OCD), Precision Psychiatry, Functional Connectivity

Disclosure:Nothing to disclose.

Tracey Shi*, Seonjoo Lee, Nikolaus Kriegeskorte, David Pagliaccio, H. Blair Simpson, Rachel Marsh

Columbia University, New York, New York, United States

Background:Obsessive-compulsive disorder (OCD) is a disabling illness that has a bimodal onset, with up to half of cases starting in childhood. Subclinical pediatric OCD (OCD) symptoms generally increase the risk of developing OCD, but the neural basis and longitudinal course of OCD symptoms remain poorly characterized. Here, using the Adolescent Brain Cognitive Development (ABCD) study to perform a powerful whole-brain analysis, we identify "profiles" or clusters of OC symptoms with similar neural underpinnings and characterize patterns of resting-state functional connectivity (rsFC ). correlate with these symptom profiles across the spectrum of severity.

Methods:The ABCD data was divided into paired training and testing subsamples. Participants completed rsFC, CBCL, and KSADS scans. Eight individual items from the CBCL (CBCL-OC Symptom Scale) were used as clinical data for the primary analyses. The RsFC data was pre-processed and the DCAN lab calculated the connectivity matrices. Participants with at least 10 minutes of non-moving data were included in the analyzes (training: n = 2846; ages 8-11 years; 1495 women; testing: away from current job). Using only the training subsample, age, gender, race, and head movement were extracted from rsFC and clinical data (“traits”). 501 rsFC features were selected for Elastic Net Canonical Correlation Analysis (eCCA) based on stable correlations with clinical features in 100 subsamples. ECCA hyperparameters were optimized by cross-validation, eCCA was performed, and significance was assessed using permutation tests. For post-hoc validation, the canonical variables were subjected to a t-test for group differences between participants with and without OCD diagnosed with KSADS.

Results:ECCA revealed 8 significant pairs of canonical variants ("profiles"). The canonical variable 1 (r = 0.47, p = 0.01) represented a clinical profile with obsessions and compulsions, as well as general symptoms such as worry and anxiety. RsFC disruption was centered in the dorsolateral prefrontal cortex (dlPFC), with symptoms associated with more positive connectivity between positive and negative task regions and weaker positive connectivity within the negative default-mode task network.

The canonical variable 2 (r = 0.39, p = 0.01) corresponded to obsessions, perfectionism and worry, but not to compulsions. This profile has been associated with rsFC traits that affect motor and sensory areas, including weaker negative connectivity with the insula and weaker positive connectivity in motor and sensory networks.

The 3rd profile (r = 0.33, p = 0.01) focused on perfectionism and fear of making mistakes, mainly without obsession. As in the first profile, the rsFCs were centered around the dlPFC. However, the connections went in the opposite direction: stronger symptoms in this profile were associated with less positive connectivity between the positive and negative regions of the task, and stronger or weaker negative connectivity within the default mode network.

Profile 4 (r = 0.36, p = 0.01) were predominantly compulsions without general bizarre behavior. This was primarily associated with connectivity spanning the frontal ocular field in the frontoparietal network, including more positive connectivity with negative task regions and weaker or more negative positive connectivity with positive task regions.

In post hoc analyses, rsFC patterns for the first 3 profiles differed significantly between participants with and without OCD diagnosed with KSADS (p < 0.03 after Bonferroni correction). Specifically, OCD diagnoses were associated with a pattern of rsFC indicative of higher OCD symptoms based on CBCL scores.

Profiles 5–8 were statistically significant (r ~ 0.30, p < 0.02), but were not discussed for reasons of space.

Conclusions:We identified 8 significant "profiles" or clusters of OC symptoms and associated patterns of rsFC disruption. The first 3, derived from quantitative relationships between subclinical and clinical symptoms of OCD, had clinical validity, as they distinguished children diagnosed with OCD from those without. One possible interpretation of these results is that Profile 1 may represent a more traditional presentation of OCD symptoms, including obsessions and compulsions, while Profiles 2-4 represent atypical presentations and/or related disorders, such as predominant obsessions, generalized anxiety, or predominant compulsions. and respectively, the different rsFC patterns associated with each clinical profile suggest different underlying network abnormalities that lead to different symptoms, potentially indicating heterogeneity that can predict the longitudinal course of symptoms or the response to interventions or treatments. The rsFC patterns for profiles 1 and 3 focus on the dlPFC, a target for transcranial magnetic stimulation for OCD due to its rich connectivity with corticostriatal loops that are dysfunctional in OCD. Furthermore, the rsFC patterns discovered here corroborate previous work showing that a disrupted balance between positive and negative task networks may be critical to the pathophysiology of OCD. Future work includes pre-publicly recording the results of this training subsample, evaluating the replication of canonical variables in the paired test subsample (derived from recent analyses), and evaluating whether these profiles predict the longitudinal progression of OCD symptoms or responses. to OCD treatment in a separate sample of participants.

Key words:fMRI at rest, obsessive-compulsive symptoms, obsessive-compulsive disorder

Disclosure:Nothing to disclose.

Leonardo Saraiva*, João Sato, Roseli Shavitt, Eurípedes Miguel, Carolina Cappi

Department of Psychiatry, Faculty of Medicine, University of São Paulo, São Paulo, Brazil

Background:Robust genetic and imaging studies have implicated genetic and neural changes in OCD, respectively. However, few studies have conducted investigations that integrate genetics and neuroimaging into the disorder. In this sense, image transcriptomics is a pioneering field that studies the gene expression signatures underlying image-derived phenotypes. This association is made using whole brain neurotypic gene expression data from the Allen Human Brain Atlas (AHBA) mapped in stereotaxic space. The Morphometric Similarity Network (MSN) is a recently proposed method that captures anatomical connectivity between cortical regions with similar cytoarchitecture and gene expression profiles. Transcriptomic imaging studies revealing the genetic and molecular factors underlying MSN trait abnormalities have been performed in major depression, schizophrenia, and neurodevelopmental disorders, but not in OCD. Therefore, this study is the first transcriptomic imaging study using MSN in OCD. Its central aim is to study gene expression signatures and their biological correlates, the underlying neuronal abnormalities associated with the disorder.

Methods:In this study, T1-weighted MRI scans of 116 OCD cases and 74 healthy controls were used. These MRIs were processed using Freesurfer's standard automated processing pipeline. A cortical subdivision was calculated on the native surfaces of the MRIs, dividing the Desikan-Killiany atlas into 308 regions of approximately equal area. Intraindividual MSNs were calculated by calculating paired Pearson correlation coefficients between z-weighted MRI feature vectors (surface area, gray matter volume, cortical thickness, intrinsic curvature, and mean curvature) for each pair of cortical regions. Measures of intra-individual (MS) regional morphometric similarity were calculated for each region by averaging its correlation coefficients with all other regions. Case-control differences for OCD in regional MS were calculated by linear regression with sex and age as covariates. Regional brain AHBA gene expression data were processed with the abagen toolbox. Partial least squares (PLS) regression was performed to assess the contribution of regional brain gene expression, as measured by AHBA, to OCD case-control differences observed in left hemisphere regional MS. It should be noted that only the left hemisphere was included in this analysis, as the right hemisphere is undersampled in the AHBA dataset. The first component of the PLS (PLS1), therefore, represents the linear combination of weighted measures of brain gene expression whose spatial distribution contributes mainly to the spatial distribution of the observed case-control differences in OCD in left hemisphere regional MS. The permutation test was used to assess the statistical significance of the variance explained by PLS1. Bootstrapping was used to estimate z scores for the PLS1 gene weights. Genes with significant positive and negative contributions to PLS1 were defined as z-scores > 3 (PLS1 + ) and  < -3 (PLS1-), respectively. The R gProfileR package was used to perform enrichment analyzes for the PLS1+ and PLS1- genes. Finally, differential gene expression (DGE) analysis of OCD cases and controls was performed on RNA-sequenced peripheral blood samples from 19 OCD cases and 19 healthy controls. Paired Spearman correlation coefficients were calculated between the z-scores of the PLS1+ and PLS1- genes and their respective log-folding changes (logFC) obtained in the DGE analyses.

Results:Statistically significant (uncorrected for multiple testing) OCD case-control differences in regional MS were found for cortical regions in both hemispheres. In the left hemisphere, these regions include frontal lobe regions (parsopercular cortices [part 1], medial rostralfrontal [part 4], and precuneus [part 6]) and parietal lobe regions (superior parietal cortices [part 5], parietal regions superior [part 9] and supramarginal [part 2]. ). In the right hemisphere, these regions include frontal lobe regions (fusiform [Part 4] and inferior parietal cortex [Part 3]) and parietal lobe regions (postcentral [Part 7] and superior parietal cortex [Part 1]). PLS1 explained 16.22% of the variance in the spatial distribution of OCD case-control differences observed in regional MS, which was statistically significant in permutation tests (p = 0.035). After estimating z-scores for PLS1 gene weights by bootstrap, 461 PLS1+ genes and 472 PLS1 genes were identified. PLS1+ genes were enriched mainly for the cerebral cortex in the Human Protein Atlas (HPA) database and for the regulation of cellular processes in the Gene Ontology Biological Process (GO:BP) database. PLS1+ genes were enriched mainly for cerebral cortex in the HPA database and for generation of precursor metabolites and energy in the GO:BP database. Finally, the z scores of the PLS1+ and PLS1- genes were negatively correlated (rho=-0.15 and -0.042, respectively) with their respective logHR obtained in the DGE case-control analysis of peripheral blood OCD. Only the PLS1+ gene correlation was statistically significant (p = 0.007).

Conclusions:This study provides compelling evidence that regional brain gene expression profiles contribute to the neuronal abnormalities associated with OCD. Furthermore, this study suggests that these brain gene expression profiles are replicated in peripheral blood.

Key words:Gene expression, genetic imaging, obsessive-compulsive disorder and related disorders, transcriptomics, brain transcription

Disclosure:Nothing to disclose.

Behrang Mahjani*, Seulgi Jung, Carolina Cappi, Marina Natividad Avila, Lily Cohen, NORDiC Consortium, EGOS Consortium, James Crowley, Kathryn Roeder, Bernie Devlin, Joseph Buxbaum, Dorothy Grice

Icahn School of Medicine at Mount Sinai, New York, New York, United States of America

Background:Obsessive-compulsive disorder (OCD) is a multifactorial disorder, which means that the risk of developing OCD is influenced by several genetic and other factors. The heritability of OCD, historically estimated through analysis of twin and family studies, is 35 to 50%. Heritability can also be estimated from individuals drawn from a population that have no obvious familial relationships, provided they have been characterized for genetic variation in their genomes. Typically, this genetic characterization uses single nucleotide polymorphism (SNP) genotypes whose alleles are common in the population. When the heritability of OCD is calculated in this way, estimates range from 25 to 43%, mainly due to covariance due to shared genetic variants. Among the environmental factors, several studies have linked the maternal condition before and during pregnancy to the risk of OCD. These factors may represent a maternal effect. Maternal effect is defined as the causal effect of maternal phenotype on offspring phenotype and can be divided into maternal genetic effect (maternal genetic nutrition) and maternal environmental effect. Maternal genetic effect occurs when the genotype that affects the phenotype of the mother affects the phenotype of the offspring, usually independent of the genotype of the child. The maternal environment effect occurs when the environment that affects the phenotype of the mother (regardless of genotype) affects the phenotype of the offspring.

Despite these results, the contribution of inherited genetic variation across the spectrum of allele frequencies and the role of maternal effects on OCD risk remain uncertain and worthy of further investigation, as they inform both our understanding of the processes underlying the OCD risk architecture and the rational design of the study. In our studies, we subdivided the OCD risk architecture by a common set of underlying genetic and environmental factors (eg, maternal effects). In addition, we identified potentially harmful rare structural variations (eg, potentially harmful copy number variation; pdCNV) and significant OCD risk genes affected by rare variations.

Methods:To examine the genetic risk architecture of OCD, we examined family data from 822,843 individuals in Sweden [7,184 (0.9%) with OCD] and SNP data from 2,090 individuals born in Sweden with a diagnosis of OCD and 4,567 matched controls. Using the genotypes of these SNPs to estimate distant familial relationships between individuals, we estimate the heritability of OCD, both overall and in partitions, based on minor allele frequency ranges (MAF). We used a subsample of these data to assess the distribution of pdCNV in OCD by examining associations between pdCNV and individual phenotypes, including accounting for early versus late diagnoses. We used analytical approaches to estimate the number of genes that may increase the risk of OCD through de novo mutations and used this estimate for power calculations for sequencing studies. In ongoing studies, these Swedish samples and others are being sequenced for rare association studies.

Results:Using familial data, we found that 35-40% of the responsibility for OCD is due to direct genetics (heritability) and 7-7.6% to maternal genetic effects. We observed evidence of significant selective mating in individuals with OCD. Furthermore, our results showed associations between parental age and maternal smoking during pregnancy with OCD risk. Using SNP data, we estimated strict SNP heritability at 29% (SE = 4%). However, in contrast to previous studies, SNPs with MAFs between 0.01 and 0.05 represented 10% of the heritability, and the estimated heritability per bin follows approximately what would be expected based on the infinitesimal model (where the risk is estimated by a large number of loci that are distributed throughout the genome and MAF containers). Nine percent of individuals with OCD carried CNVpd, indicating that 1 in 11 OCD cases may have a genetic diagnosis of CNV. The most frequently found pdCNV was in the 16p13.11 region. There were no significant differences in the frequency of pdCNV between individuals diagnosed early and late with OCD. Using published data, we estimate that deleterious mutations in approximately 200 different genes may increase the risk of OCD, motivating high-throughput sequencing for OCD gene discovery. Sequencing of 8,000 samples is ongoing.

Conclusions:Our results provide new insights into TOC risk architecture. We show that the maternal effect, combined with the effects of rare and common variants, shapes much of the risk architecture of OCD. We found that genetic variation affects OCD risk across a wide spectrum of allele frequencies. Studies from other groups have shown that ultra-rare de novo mutations are also part of the risk of OCD and we hope to see this in our ongoing sequencing studies.

Key words:Obsessive Compulsive Disorder, Heredity, Genetics, Rare Genetic Variation, Copy Number Variants

Disclosure:Nothing to disclose.

Seulgi Jung, Carolina Cappi, Marina Natividad Avila, NORDIC Consortium, EGOS Consortium, Kathryn Roeder, James Crowley, Behrang Mahjani, Joseph Buxbaum, Dorothy Grice*

Icahn School of Medicine at Mount Sinai, New York, New York, United States of America

Background:OCD is a neurodevelopmental psychiatric disorder that affects approximately 3% of the population. For years, our understanding of the genetic architecture and risk factors for OCD has lagged behind other major psychiatric disorders. However, as OCD genetic cohorts and sample sizes increase, we have the opportunity to expand our understanding of OCD risk architecture. Early studies provide compelling evidence for the importance of genetic risk factors in OCD. In family studies, the odds of OCD in relatives of cases compared with controls were 4.6 to 5.0 in first-degree relatives, 1.5 to 2.3 in second-degree relatives, and 1.4 in second-degree relatives. third degree. The heritability of obsessive-compulsive disorder has been estimated to be 27-56% and the SNP-based heritability to be 25-43% in familial studies. Although previous studies have suggested that inherited risk variation tends towards the most common variants, our group has recently shown that variants across the allelic spectrum contribute significantly to the heritability of OCD. Early and recent copy number variation (CNV) studies have supported a role for rare de novo mutations in OCD. Taken together, these results suggest that additional rare and inherited variants contribute to OCD risk. Indeed, full exon sequence (WES) studies of OCD cases support a role for rare single nucleotide variations (SNV) in OCD risk, including de novo mutations. Cappie et al. found that rates of de novo mutations, likely protein truncation variation (PTV), are significantly increased in triplets with OCD. Likewise, Halvorsen et al. observed a 1.3-fold increase in deleterious de novo variants in OCD cases compared to controls, including a 2.6-fold increase in de novo PTV in restricted genes. To identify genes that increase the risk of OCD if they harbor rare deleterious mutations, we are sequencing 8,000 samples while simultaneously integrating data from existing and new TOC-WES studies. We are currently analyzing published and unpublished data on cases of OCD with parental or ancestral control.

Methods:So far, we have new WES data covering 160 Mount Sinai cases and 480 Swedish OCD cases, along with over 2,800 corresponding parentage tests. We also analyzed previously published WES data. To retrieve SNV and Indel variants from WES data, we use the current Genome Analysis Toolkit (GATK) protocol. We perform quality control steps, including verifying the accuracy of reported genealogical information (outlier samples are removed) using Hail (an open source framework for scalable genetic data analysis). The variants were annotated using the Variant Effect Predictor (VEP), prioritizing the encoding of the canonical transcripts. We then performed genetic analyzes using the Transmitted and De Novo Association (TADA) model of gene discovery.

Results:All genes were ranked by P-value and restriction scores noted, including restriction for PTV and nonsense variation in TADA analysis. The top 10 genes were CHD8, INO80, SCUBE1, ZMYM2, ADIPOR2, EIF3G, TP53BP2, KMT2B, PITPNM2 and TRRAP. Three potentially new OCD genes: EIF3G, KMT2B and TRRAP are already known neurodevelopmental genes. (1) EIF3G, with deleterious missense variation in Cappi et al. and in a sample from Mount Sinai, it is also a likely risk gene for autism. (2) Cappi et al. report PTV again in KMT2B, and we observed 1 missense with MPC > 2 in a Swedish case. Interestingly, a missense de novo mutation in KMT2B was also observed in a Chinese case (Lin et al.). KMT2B encodes lysine methyltransferase 2B. Interstitial deletions or pathogenic KMT2B mutations cause a dystonia syndrome that occurs in the first or second decade of life and may include psychiatric comorbidities such as mild intellectual disability (ID), attention deficit hyperactivity disorder (ADHD), anxiety, and obsessive disorder -compulsive disorder. 🇧🇷 (3) TRRAP encodes a large multidomain protein of the phosphoinositide-3-kinase-related kinase family with de novo mutations that have been reported in autism, ID, schizophrenia, and early-onset psychosis with OCD. Furthermore, based on parameters such as de novo mutation rates and relative hazard rates estimated from the data underlying these studies, we estimate that approximately 200 OCD genes could be discovered using these approaches.

Conclusions:As seen in ID and autism, de novo mutations in OCD are highly enriched for highly conserved genes. This represents less than 10% of all genes when comparing people with OCD to people with no known psychiatric phenotype. We took advantage of this and began to discover genes that increase the risk of OCD when those genes are affected by a rare deleterious variation. We also see overlap with known ASD and ID risk genes, as well as interesting associations with known syndromic genes.

Key words:Obsessive Compulsive Disorder, Genetics, Rare Variation

Disclosure:Nothing to disclose.

Wan-wa Wong, Rangaprakash Deshpande, Reza Tadayon-Nejad, Joel Diaz, Andrew Leuchter, Gerhard Hellemann, Jamie Feusner*

University of Toronto, Center for Addiction and Mental Health, Toronto, Canada

Background:Body dysmorphic disorder (BDD) is characterized by preoccupation with misperceived appearance defects that they believe make them ugly and disfigured. Visual information processing disorders in BDD appear to be central neurobiological contributors to the psychopathological hallmark of cognitive disorders. Previous neuroimaging studies have found abnormally reduced dorsal visual stream (DVS) activity in BDD when viewing filtered images that convey configurational/holistic information, contributing to a pattern of imbalances in global versus local visual processing. Some evidence has shown that the magnocellular pathways in the DVS are tuned for fast imaging, allowing global/holistic but not local/detailed visual processing. Furthermore, ventral visual current (VVS) regions appear to reduce the magnitude of activation with higher stimulus frequency/shorter stimulus duration. Thus, we investigated whether the DVS/VVS systems could be altered during rapid facial presentation in people with DCD. In addition, we tested whether intermittent theta burst stimulation (iTBS), a form of repetitive transcranial magnetic stimulation, could further enhance the effects of rapid facial presentation as quantified by the dynamic effective connectivity (DEC) model.

Methods:Fourteen adults not treated with BDD were randomized to active (n=7) or sham (n=7) iTBS treatment. Stimulation targets were the left and right lateral parietal cortices (corresponding to PC3 and PC4 in the EEG 10-10 system). Stimulation was applied at 100% active motor threshold (AMT) for the active group and 10% AMT for the sham group. We then immediately acquired fMRI data from the participants as they viewed photos of their own faces for short (125ms, 250ms, 500ms) and long (3000ms) periods. As an additional comparison, given the possibility of sham stimulation effects, the data were also compared to data collected separately from 38 BDD participants and 29 healthy controls during an identical facial visualization task but without prior iTBS. Participants with BDD met the DSM-5 criteria for BDD with facial problems.

Fourteen regions of interest (ROI) were selected in DVS and VVS: 2 ROIs in primary visual cortex (V1) [bilateral calcarine], 6 ROIs in VVS [bilateral inferior occipital gyrus (IOG), fusiform gyrus (FG) and temporal gyrus) inferior (ITG)] and 6 ROI in DVS [bilateral superior occipital gyrus (SOG), inferior parietal gyrus (IPG) and superior parietal gyrus (SPG)]. Hemodynamic deconvolution was then performed on the time series extracted from these ROIs to minimize within-subject variability of the hemodynamic response function and improve the estimation of effective connectivity. DEC, a dynamic measure of directional connectivity between pairs of ROIs, was calculated at each time point using time-varying (GC) Granger causality based on the Kalman filter. Twelve intrahemispheric connections were selected and classified into 4 categories: 1) lower SVV (calcarine for IOG), 2) upper SVV (IOG for FG; IOG for ITG), 3) lower DVS (calcarine for SOG) and 4) DVS higher (SOG to IPG; SOG to SPG). A mixed linear model was used to analyze the data (fixed factors: group [BDDActive_iTBS, BDDSham_iTBS, BDDNo_iTBS or HCNo_iTBS], duration [125ms, 250ms, 500ms or 3000ms], category [Lower VVS, Higher VVS, Lower DVS or Higher DVS] ; random factor: participants).

Results:For positive GC values, there was a significant three-way interaction between group, duration, and category of fixed effects tests (F[27, 135614]=1.89, p=0.004). For greater DVSH, the active group had greater DEC than BDD without iTBS across all four durations, achieving similar scores to controls.

Conclusions:In this proof-of-concept study, we investigated the effects of interactions between excitatory neuromodulation and rapid facial presentation on dorsal visual stream connectivity and ventral visual stream connectivity in BDD. iTBS-induced excitatory neuromodulation enhanced dynamic connectivity for DVSHigher, reaching levels similar to healthy controls. These results, demonstrating target binding and modulation, have implications for the development of new cognition retraining treatments to correct appearance perception biases in people with BDD.

Key words:Body dysmorphic disorder, repetitive transcranial magnetic stimulation (rTMS), visual perception, effective connectivity, perceptual distortion of appearance

Disclosure:Nothing to disclose.

McKenzie Schuyler*, Bowie Duncan, Daniel Geller, Amitai Abramovitch

Massachusetts General Hospital, Boston, Massachusetts, USA

Background:Obsessive Compulsive Disorder (OCD) is associated with significant impairments in several areas. In fact, OCD is associated with worse long-term educational achievement, occupational problems, and cognitive dysfunction. Compared to adults, young people with OCD have relatively better cognitive function. However, they may have more difficulties relating to family and peers and may need more support in the school environment compared to healthy controls. Few studies have examined these issues directly. Furthermore, research examining the impact of comorbidities on psychosocial functioning in pediatric OCD is limited. The aim of the present study was to directly assess psychosocial functioning in a large, well-characterized sample of children and adolescents with OCD.

Methods:The study included 100 children and adolescents with OCD (MAGE = 11.42; 42.0% men) and 138 controls without OCD (MAGE = 11.45; 42.8% men). Participants were given a range of measures, including the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) to assess diagnostic status and comorbidities, the Yale-Brown Childhood Obsessive Compulsive Scale (CY-BOCS) to assess the severity of OC symptoms and the Social Adjustment Inventory for Children and Adolescents (SAICA) to assess psychosocial adjustment and the Family Environment Scale (FES) to assess family functioning. In addition, information about repeat classes, special grade classes, and additional help/tutoring was obtained from teachers and parents. We performed independent-sample t-tests to examine group differences in psychosocial, family, and school functioning variables.

Results:Compared with controls, adolescents with OCD had significantly more problems with school behavior (p = 0.001; Cohen's d = 0.43), problems with leisure activities (p = 0.000; d = 0.89), problems with activities of peers (p = 0.000; d = 0.71) and problems with parents (p = 0.001; d = 0.49). Families of adolescents with OCD also had significantly higher scores than controls for current and past family conflict (p = 0.035, d = 0.28 for both) and reduced scores for current and past family cohesion (p = 000 , d=0.51; p=018, d=0.32). There were no differences in the family expression subscale. Young people with OCD attended special courses (0.7% vs. 4.3%, p<0.0001) and received additional help (10.2% vs. 64%, p<0.0001) compared to controls classes u specials with different SAICA subscales, however, did not correlate with the FES subscales. Finally, comorbid hyperactivity with attention-deficit activity disorder, conduct disorder, and oppositional defiant disorder led to another pattern of difficulty, primarily in the area of ​​academic conduct problems.

Conclusions:Although pediatric OCD is not associated with significant cognitive impairment, this population receives more extra help at school, is more likely to be enrolled in special classes, and has significantly more psychosocial and family problems than the control group. In addition, there is a differential impact of various comorbid disorders on psychosocial problems in this population. These results reinforce the need for careful screening for OCD in this age group, including assessment of comorbidities. More research is needed to examine how validating seeking versus measurable academic deficits contribute to helping seeking in this demographic.

Key words:Obsessive Compulsive Disorder (OCD), Pediatrics, Study of the Family

Disclosure:Nothing to disclose.

Leonard Lerer*, Alexander Botvinnik, Katherine Spear, Orr Shahar, Patryk Lipski, Haley Calderon, Karin Blakolmer, Tzuri Lifschytz, Bernard Lerer

Rear of Algae Sciences Yards, Chicago, Illinois, USA

Background:Anecdotal reports suggest that the behavioral and pharmacological effects of psilocybin-containing "full spectrum" Psychedelic Mushroom Extract (TBE) differ in type and intensity from those of chemical psilocybin (PSIL). A limited number of rodent studies have compared synthetic psilocybin (or psilocin) to raw psychedelic mushroom extract. Furthermore, psychedelic mushrooms contain psilocybin biosynthetic pathway intermediates such as baeocystin, norbaeocystin, and aeruginascin, which may affect the nature of psilocybin's effect ("entourage effect"), along with other components such as armines with monoamine oxidase-inhibitory properties. . In the current study, we compared the effect of PSIL versus TBE on the mouse head muscle twitch (HTR) response, which correlates with psychedelic effects in humans, in a rodent antidepressant screening assay and in a phenotypic fish behavioral model. -zebra.

Methods:Male C57Bl/6j mice were used in all head movement experiments. PSIL (98.75% purity) was provided by the Usona Institute. BYAS-PEB provided FSME, a methanol extract of Psilocybe cubensis with a psilocybin content of 1.5%. Drug doses were calculated so that equal injection volumes of PSIL and TBE contained equal concentrations of psilocybin in mg per kg. Control mice received injections of vehicle (VEH) (0.9% NaCl solution). HTR was measured for 20 minutes on a magnetometer-based system using ear clip magnets. The tail suspension test (TST) was performed using a Noldus Ethovision system by observers blinded to treatment status 48 hours after drug administration. A male zebrafish (Danio rerio) was used in a behavioral phenotyping experiment in an open arena. The drug dose, 3 mg/l PSIL and TBE, was administered in a beaker with 200 ml of water over 10 minutes. Control fish were placed in a beaker containing 200 mL of water for 10 min. The fish were then placed in an arena measuring 50 x 50 x 4 cm and monitored by video using idTracker software, recording trajectories for 20 minutes immediately after treatment and for 20 minutes 80 minutes after treatment.

Results:TBE at a psilocybin dose of 4.4 mg/kg over 20 min elicited significantly more head shakes than PSIL at the same dose (F = 4.41, df 1.21, p = 0.04 ; TBE n = 11, PSIL n = 12). The difference became apparent over time. In the Rear Suspension Test (TST) performed 48 hours after i.p. Administration of PSIL (4.4 mg/kg), TBE (psilocybin content 4.4 mg/kg) or VEH, both PSIL (209.3 ± 93.6 s, n = 11, p = 0.01) and TBE (198.14 ± 61.3 s, n = 10), p = 0.0006) also showed significantly less inactivity than VEH (296.0 ± 33.8 s, n = 11). In the highly active TST measurement, TBE (11.38 ± 10.13 s, n = 10) induced significantly greater activity than VEH (0.04 ± 0.12, n = 11, p = 0.0007) and PSIL (0.53 ± 1.04 = s, 11, p = 0.001). In the zebrafish experiment, 2D spatiotemporal reconstructions of zebrafish swim lanes during the first 20-minute recording period revealed clearly visible differences in swimming patterns, including speed, distance swum, mean distance to perimeter and to the center and changes in direction. between control and zebrafish. TBE/PSIL groups. There were also a number of notable differences in swimming patterns between the TBE and PSIL groups, particularly related to the mean time spent in sand corners (P<0.05; TBE/PSIL n=9). At 80 min, the swimming pattern of the PSIL group closely resembled that of the control group, while the TBE group continued to exhibit a similar and slightly moderated swimming pattern as in the initial 20-minute recording period.

Conclusions:A previous study by Zhuk et al. (2015) suggested that mushroom extract has a greater potency to induce HTR than psilocin (the active metabolite of psilocybin). Our findings in mice are consistent with this observation. Furthermore, we show that TBE produces a stronger effect than PSIL on the TST, a screening test for antidepressant potential, when the same dose of psilocybin is administered with both preparations. Furthermore, this work provides evidence of a robust and measurable zebrafish response to PSIL and TBE. The longer lasting effect of TBE may indicate an "entourage effect". More studies are needed to elucidate the potential therapeutic benefits of full-spectrum psychedelic mushroom extract compared to chemical psilocybin and to identify the entourage molecules that contribute to these effects. This work also presents an attractive and important challenge related to the possible development of a zebrafish behavioral model equivalent to the HTR assay in mice.

Key words:Psilocybin, psychedelics, entourage effect, head twitch response, tail-hanging test

Disclosure:Back of the Yards Algenwissenschaften: Fundador (auto)

Sandeep Singh, Alexander Botvinnik, Orr Shahar, Gilly Wolf, Amit Lotan, Bernard Lerer*, Tzuri Lifschytz

Hadassah Hebrew University Medical Center, Jerusalem, Israel

Background:Initial clinical results, supported by preclinical studies using behavioral paradigms such as marble burial, suggest that the psychedelic psilocybin tryptamine may be effective in the treatment of obsessive-compulsive disorder (OCD). The objectives of this study were to further evaluate the role of 5-HT2A receptors in the marble burying effects of psilocybin, to investigate the role of 5-HT1A receptors in this effect, and to investigate the potential use of the psilocybin partial agonist 5-HT1A receptor, buspirone, as a concomitant treatment of OCD with psilocybin

Methods:Male ICR mice received psilocybin 4.4 mg/kg, escitalopram 5 mg/kg; the 5-HT1A agonist, 8-OH-DPAT 2 mg/kg; the 5-HT2A antagonist M100907 (volanserin) 2 mg/kg; the 5-HT1A partial agonist, buspirone, 5 mg/kg; or the 5-HT1A antagonist, WAY100635 2 mg/kg; or combinations. Drugs were administered intraperitoneally and mice were subjected to the marble burial test (MBT) for 30 minutes after treatment. The witches' head response (HTR) induced by psilocybin alone or in combination with buspirone was studied in a magnetometer-based assay.

Results:1) Both psilocybin (p<0.01) and the positive control, escitalopram (p<0.01), significantly reduced marble burial. The effects of psilocybin were not attenuated by the 5-HT2A antagonist M100907. The 5-HT1A agonist, 8-OH-DPAT, reduced marble burying (p<0.01), as did the 5-HT1A partial agonist, buspirone (p<0.01). The effect of 8-OH-DPAT was additive to that of psilocybin (p < 0.01), but that of buspirone was not. The 5-HT1A antagonist WAY100635 attenuated the effects of 8-OH-DPAT and buspirone on marble burials, but not the effects of psilocybin. 2) Psilocybin injections over 3.5 hours had no effect on marble shedding and the bolus injection effect was not sustained. 3) Co-administration of buspirone with psilocybin blocked psilocybin's effect on RTH but not its effect on marble burial.

Conclusions:Neither 5-HT2A nor 5-HT1A receptors are fundamentally involved in psilocybin's effect on the marble shed. Co-administration with buspirone may block the psychedelic effects of psilocybin without interfering with its anti-obsessive effects. Treating OCD with buspirone and psilocybin at the same time is a viable strategy to achieve anti-obsessive effects and avoid or minimize the psychedelic trip.

(supported in part by Back of the Yards algae sciences and Parow Entheobiosciences)

Key words:Psychedelics, Obsessive Compulsive Disorder (OCD), Psilocybin, Buspirone, 5-HT1A Receptors

Disclosure:Back of the Yards Algae Sciences: Contract Research (auto), Parow Entheobiosciences: Contract Research (auto), Negev Capital: Consultants (auto)

Lucas Remoaldo Trambaiolli*, Freddyson J. Martínez-Rivera, Wei Tang, Mary Phillips, Gregory Quirk, Suzanne Haber

McLean Hospital, Harvard Medical School, Belmont, Massachusetts, EUA

Background:The caudal 47/12 region of the ventrolateral prefrontal cortex (vlPFC) was recently described as the nodal point of the network of prominence in humans and non-human primates (NHP) (Trambaiolli et al. 2022 eLife). This region supports predictions of stimulus outcomes associated with salient stimuli and prepares appropriate responses, which are then selected by the anterior cingulate cortex (ACC).

In the rodent sustained avoidance circuit, the lateral agranular insular/orbital (AI/LO) cortex has excitatory inputs to the rostral prelimbic cortex (rPL) (Martínez-Rivera et al. 2022 Biol. Psych.). These neurons project to the ventral striatum (SV) to control avoidance expression. Underactivity in AI/LO decreases the excitatory drive from rPL to SV, increasing the susceptibility of SV to excitatory input from the basolateral amygdala (BLA). This leads to the expression of avoidance.

Here we hypothesize that (i) the caudal primate 47/12 encompasses the identified AI/LO region in rats and (ii) similar avoidance pathways in NHP using data from a. can be identified from the river 47/12.

Methods:We injected bidirectional tracers in the vlPFC area 47/12 (four injection sites) and in the ACC (two injections in area 32 and three in area 24), anterograde tracers in the BLA (two injections), and retrograde tracers in the o vs. (two injections). injections).

We used brightfield microscopy to identify which sublocations in vlPFC and ACC are strongly interconnected. We quantified the number of labeled cells in 23 cytoarchitectural regions in the frontal cortex and amygdala. The strength of connectivity between each cortical area and the injection site was measured as the ratio of the number of cells in that area to the total number of labeled cells.

We used darkfield microscopy to delineate axonal projection zones between all avoidance circuit nodes (vlPFC, ACC, SV, and BLA) from the locations identified in the previous step. Finally, we validate the connectivity strength of the vlPFC, ACC, and BLA projections for the VS using the same retrograde approach described above.

Results:Area 24 was the ACC portion with the strongest projections for the vlPFC and showed a rostrocaudal gradient peaking at the most caudal portion of 47/12. The strength of vlPFC connections to the ACC peaked in the pregenual portion of area 24 (rostral 24). Darkfield analysis validates the bidirectional projections between caudal 47/12 and rostral 24, with dense fields of axon terminals at both locations.

The rostral region 24 has dense projections for the SV (nucleus that extends to the carapace) and BLA. Other ACC regions and the caudal 47/12 show weak or no projections for these regions. The BLA projects next to the VS (mainly the tank), vlPFC and ACC. It is important to note that the BLA and rostral 24 projections overlap at the boundary between the layer and the VS nucleus. Retrograde injections in VS validate these patterns.

Conclusions:These findings suggest that anatomical connections relevant to the persistent avoidance circuit in rodents are also present in NHP. Caudal NHP 47/12 probably contains the AI/LO node of this circuit, and rostral 24 is believed to be homologous to the rPL. Caudal 47/12 has weak to absent projections to subcortical regions of interest and focuses its loop control on interactions with the rostral ACC.

Abnormal caudal stones 47/12 can result in pathological behaviors such as B. the persistent avoidance seen in patients with obsessive-compulsive disorder (OCD). Importantly, the caudal 47/12 receives dense projections from the BLA, which can lead to biased attention to negative stimuli and inadequate response preparation. This is consistent with recent studies reporting that patients with OCD have hyperconnectivity between the caudal 47/12 and the amygdala compared to healthy controls (Thorsen et al. 2020 Neuroim. Clin.). This association can also be compared with that of elusive rodents (Martínez-Rivera et al. 2022 Biol. Psych.) or in the caudal 47/12 of OCD patients (Chase et al. 2020 Neuroim. Clin. ).

The VS is a descending region where the avoidance behavior is activated or stopped. Rostral 24 and BLA converge at the same VS location (skin-core boundary). This region is a common target for deep brain stimulation in OCD patients, and rodent models suggest that its effectiveness is due to increased anxiety suppression (Rodriguez-Romaguera et al. 2020 PNAS). Given its role in the avoidance loop and the homologies between NHP and humans, the 47/12 flow may be an additional target within this loop to treat these symptoms in OCD.

Key words:Ventrolateral prefrontal cortex, sustained avoidance, obsessive-compulsive disorder, anterior cingulate cortex (ACC), ventral striatum

Disclosure:Nothing to disclose.

Matthew Geramita*, Susanne Ahmari, Eric Yttri

University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Background:Patients with obsessive-compulsive disorder (OCD) have deficits in making decisions based on both value and safety. The dorsomedial striatum (DMS) likely plays a critical role in these disorders, as the DMS encodes safety and value and exhibits abnormal activity in patients with OCD. However, it is not known how DMS representations of value and uncertainty contribute to behavior. To answer this question, we recorded and manipulated DMS activity during a Pavlovian conditioning task in which value and uncertainty were modulated.

Methods:Mice (n = 10; 5 females) expressing channelhodopsin-2 in medial spinous neurons of the direct or indirect pathway (dMSN or iMSN) had bilateral optic fibers implanted in the DMS (anterior-posterior: +0.7 mm, mediolateral: +/- 1.5 mm, dorsoventral: −2.5 mm) and trained to perform a head-mounted Pavlovian auditory conditioning task, in which three types of cues predicted a reward of 0%, 50%, or 100% of the tests. To manipulate activity, dMSNs or iMSNs were briefly stimulated bilaterally (473 nm; 2 mW; 15 Hz for 1 s) during the signal, delay, or result period. In a separate cohort of animals (n = 3; 1 female), MSN activity was recorded using Neuropixels electrodes.

Results:The mice learned the value of each auditory stimulus as the expected licking rate during the signaling and delay time, which correlated with the probability of reward (0%: 1.2 ± 0.1 Hz; 50%: 4.4 ± 0.2 Hz; 100%: 5.1 ± 0.1 Hz; One-way ANOVA, p < 10-32). In a population of 343 putative MSNs, 51% were modulated by all three signals (ie, prominence) equally, 40% were modulated by signal value, and 8% were modulated by signal certainty. Unsupervised clustering of activity during the cue and delay periods revealed four distinct response patterns: two that were positively modulated and two that were negatively modulated by cues. Value, emphasis, and certainty neurons were evenly distributed across the four groups. Interestingly, the signaling activity of neurons belonging to the two excitatory groups correlated negatively with the licking of 50% of the signals (group 1: r = -0.091 ± 0.01, p < 10-8; group 2: r = -0.085 ± 0.01 ; p < 10-11), but not 0% or 100% of the signs. These data suggest that a subpopulation of DMS MSN negatively modulated anticipatory licking during uncertain cues, regardless of whether the neurons encode information about cue value, emphasis, or certainty. Cell-type specific modulation of MSN confirmed in vivo data. Photostimulation of dMSN or iMSN during the 50% signaling period reduced anticipatory licking (no stimulation: 4.4 ± 0.3 Hz; vs. stimulation: 2.8 ± 0.3 Hz; t, test p < 0.001 ). Surprisingly, there was no change in anticipatory licking when dMSN or iMSN were stimulated during the 100% or 0% signal. Furthermore, photostimulation of any of the populations during the latency period or due to any kind of suggestion did not change licking.

Conclusions:DMS plays an important role in decision-making in various contexts, but it is not known how value and certainty regulate value-based behavior. Here, using in vivo electrophysiology and optogenetics, we found that DMS-dMSN and iMSN activity inhibit anticipatory licking during uncertain but indeterminate signals. These results suggest that reward certainty controls the impact of DMS activity on behavior.

Key words:Dorsal striatum, uncertainty, value-based decision making

Disclosure:Nothing to disclose.

Aarti Jajoo, Christos Chatzinakos, Cindy Wen, Tade Souaiaia, Tim Bigdeli, Michael Gandal, Nikolaos Daskalakis*

McLean Hospital, Harvard Medical School, Belmont, Massachusetts, EUA

Background:Brain transcriptomic imputation uses genotypic expression reference panels to create predictive models of genetically regulated gene expression (GReX). GReX models can be applied to GWAS to perform transcriptome-wide association studies (TWAS) to prioritize genetic trait associations (GTAs) with functional importance. However, reference panels and GWAS studies were biased towards samples of European descent (EA), presenting limitations for identifying generalizable GTAs. To address this challenge, we propose to perform a meta-analysis of TWAS results across ancestors, applying lineage-specific models to the GWAS of the respective ancestors.

Methods:To this end, we trained lineage-specific GReX models of mixed African descent (AA) and AD separately for healthy adult DLPFC tissue (NAA = 165, NEA = 453 subjects) and fetal brain tissue (NAA = 164, NEA = 292) . 🇧🇷

Results:Fetal models predict fewer genes and have lower R2 model performance for overlapping genes compared to adult models of the same ancestry (R2=0.17 for AD_adult vs. R2=0.11 for AD_fetal, P<e -16). Within each tissue type, R2 was comparable across ancestors, but AA models predicted 45% fewer genes compared to EA models from the same tissue, likely due to lower performance. EA models performed worse compared to AA models on the AA test set, while AA models performed comparable on the EA test set. We applied these models to the GWAS of bipolar disorder (BD), major depressive disorder (MDD), post-traumatic stress disorder (PTSD), and schizophrenia (SCZ), using at least one GWAS for each lineage within each disorder. The mean correlation of GTA z scores was Rho = 0.49 between the analysis of adults and fetuses. Fetal tissue produced a higher percentage of GTA for SCZ, as expected from neurodevelopment, but surprisingly this was true for PTSD, which has a later age of onset and lower heritability. Common GTAs from fetal and adult analyzes tend to cluster in specific genomic regions (eg, 17q21.31 in PTSD). Furthermore, the general observation is that two-ancestor TWAS meta-analysis using only EA-GReX models yields the lowest percentage of significant Bonferroni GTAs, whereas using ancestor-specific GReX models for the respective ancestor-GWAS yields the highest percentage (z in SCZ, 30-fold increase in PTSD).

Conclusions:Our work shows that GTAs based on fetal and adult brain tissue reveal common and distinct genetic underpinnings of psychiatric disorders that occur at various stages, and that dual ancestral TWAS is most beneficial when lineage-specific GReX models are applied to the respective specific ancestors. able. GWAS.

Key words:Genetic lineage, gene expression, fetal brain, adult brain

Disclosure:Nothing to disclose.

Laverne Melon*, Han Bin Kwon, Isabella Ahearn, Bilge Buyukdemirtas

Wesleyan University, Middletown, Connecticut, EUA

Background:Sensitivity to the stimulant effects of alcohol predicts the diagnosis of AUD and the severity of symptoms (King et al., 2021). Preclinical models of repeated alcohol exposure that sensitize this stimulatory effect are useful tools for understanding the maladaptive plasticity underlying the transition from drinking to disordered drinking. Furthermore, gender differences in these preclinical models can be used to further analyze which biological systems altered by alcohol sensitization are relevant to specific drug outcomes. To this end, we used a chemogenetic approach to analyze a role of GABAergic inhibition in the VTA on priming expression and gender-specific reduction in social reward preference after alcohol-induced priming.

Methods:Male and female C57BL6/J mice (5-8/group) repeatedly received alcohol (2.0 g/kg) for 14 days and locomotor activity was assessed on the first and last day of exposure. Animals were given the opportunity to interact with a sexually immature pup for 5 minutes during initial (1 day after last exposure) or extended (14 days after last exposure) deprivation. Brains and blood were collected 30 minutes after this opportunity for social interaction.

To test the role played by GABAergic inhibition in the ventral tegmental area in this sex difference, male and female VGAT-cre mice (7–9/group) received 250 nL of Gi-DREADD virus (pAAV-hSyn-DIO-hM4D (Gi )- mCherry) or the fake mCherry virus (pAAV-hSyn-DIO-mCherry) in the VTA. Animals received a single administration of CNO (1.0 mg/kg, ip) and were tested for alcohol reactivity (2.0 mg/kg) 7 or 14 days later.

Results:Both males and females showed a sensitized response to ethanol at this dose, although the effect was more pronounced in females. Although both groups showed no change in preference for social interaction during early weaning from this priming protocol, females showed a significant reduction in social preference two weeks after their last exposure to ethanol. We found that a single inhibition of VTA-GABA neurons induced increased activity at baseline seven days later in both males and females. However, two weeks after this acute chemogenic inhibition of VTA-GABA neurons, only males showed a significantly greater locomotor response to ethanol (p = 0.014). Current analysis of the impact of this manipulation on sensitivity to social interaction is ongoing.

Conclusions:The results indicate that acute inhibition of VTA GABAergic neurons has a sexual diergic effect on post-ethanol reactivity, and this may underlie the sexual plasticity in post-drug exposure behavior.

Key words:Alcohol, Sensitization, GABA, VTA, Gender Difference

Disclosure:Salbei-Therapeutika: Grant (automatic)

Monica Faulkner*, Mehdi Farokhnia, Lisa Farinelli, Sara Deschaine, Brittney Browning, Fatemeh Akhlaghi, Lorenzo Leggio

National Institute on Substance Abuse, Baltimore, Maryland, USA

Background:Ghrelin is a 28 amino acid peptide that acts as an endogenous ligand for the Growth Hormone Secretagogue Receptor (GHS-R1a). Ghrelin has also been found in preclinical studies to increase ethanol intake by modulating the neural mechanism of reward processing. Clinical studies have also demonstrated the role of ghrelin in alcohol use behaviors, showing that ghrelin levels are suppressed by acute oral and intravenous alcohol administration, and that baseline ghrelin levels are positively correlated with alcohol cravings. Increased ghrelin significantly reduced alcohol craving and alcohol self-administration and influenced increased neural activation of the amygdala and medial orbitofrontal cortex during an alcohol-related stimulus delay task in people with ASD who are not seeking treatment.

We recently evaluated the safety and tolerability of a novel ghrelin receptor inverse/concurrent antagonist, PF-5190457, when co-administered with alcohol. Although our focus was on safety, in a small subset of the study we did preliminary tests of the drug's effect on alcohol cravings and found that it reduced alcohol cravings in a bar-like laboratory. Based on these preliminary results, we extended our investigation of PF-5190457 to specifically assess drug effects on alcohol and eating-related behaviors in a sample of hospitalized AUD patients requiring treatment.

Methods:The study was a double-blind, placebo-controlled, between-subject clinical trial evaluating the effects of PF-5190457 100 mg b.i.d. on steady-state alcohol/food-related behaviors. Participants were twenty-nine detoxified individuals seeking AUD treatment (M = 21, F = 8). Participants completed 2 behavioral paradigms to assess 1) whether the drug would reduce food and alcohol cravings, which were evaluated in a "bar-like" laboratory, and 2) to assess whether the drug improved food choice would be reduced by "a" virtual buffet held in a virtual reality environment. To assess alcohol and food cravings, participants were exposed to their favorite alcoholic beverage and snack in a laboratory-style bar. The procedure began with an initial assessment of alcohol cravings measured by the Alcohol Urge Questionnaire (AUQ) and food cravings measured by the General Food Craving Questionnaire-State (GFCQ-S) outside the bar as a laboratory. After the baseline assessment, participants were escorted to the bar and exposed to alcohol, food, and neutral signals (water). There was 1 contact with the neutral signal (water), 1 contact with the food signal (your favorite snack) and 2 contacts with the alcohol signal (your favorite alcoholic drink). After each exposure, participants completed the Alcohol Urgency Questionnaire (AUQ) to assess alcohol craving, the General Food-State Desire Questionnaire (GFCQ-S) to assess craving for food, and an additional questionnaire after each exposure. to alcohol on the Attention to Alcohol Scale (AAS), which evaluates your attention to alcoholic beverages.

To assess food-choice behavior, participants attended a virtual lunch buffet, during which they chose as many virtual foods and beverages as they normally would during lunch during a walk to the buffet, and then filled out questionnaires to assess craving. current alcohol (AUQ) status. Desire to eat (GFCQ-S) and affective mood (POMS). Participants' food selection behaviors were assessed by calculating the total calories selected during the virtual lunch buffet.

Repeated measures ANOVA was used to analyze study results, and all analyzes were controlled for body mass index (BMI), acyl ghrelin levels, and age on day 1 of the study, as well as gender and subject rank.

Results:The drug did not reduce the craving induced by the alcohol stimulus measured by the AUQ (F1.5 = 0.11, P = 0.738) and there was no drug-time interaction (F1.5 = 0.72, P = 0.607). There was a significant effect of the drug on alcohol awareness, with participants reporting less attention to the smell of alcohol (F1.31= 4.88, p= 0.035) and having to make less effort to stop drinking to think about alcohol (F1 , 46 = 5.94 p = 0.02).

There was also a significant drug effect on food choice behaviors, with participants making fewer caloric choices during the virtual lunch compared to the placebo condition (F1,29,6=4.49, p=0.043).

Conclusions:We found that the novel ghrelin receptor inverse agonist PF-5190457 had a significant impact on food choice behavior during a virtual lunch buffet and an impact on attention to alcohol stimuli during a stimulus reactivity paradigm in a laboratory setting. However, there was no effect of the drug on the food stimulus evoked in the laboratory by alcohol or bar. These preliminary results suggest that ghrelin may play a role in attention to reward-related cues and stimuli, but not in craving for detoxified individuals with AUD. Future research should examine different stages of the AUD cycle to assess whether ghrelin antagonism has similar effects at all stages.

Key words:Alcohol Use Disorder: Treatment, Clinical Trial, Ghrelin

Disclosure:Nothing to disclose.

Lionel Rodriguez*, Matthew Nguyen Tran, Elizabeth Pattie, Heena Divecha, Leonardo Collado-Torres, Stephanie Cereceo Page, Keri Martinowich

Lieber Institute for Brain Development, Baltimore, Maryland, EUA

Background:The lateral septum (LS) is a basal midline region of the forebrain surrounded by the lateral ventricles. The LS is a sensory and affective integrator that uses environmental stimuli to modulate behavior. In the rodent, the LS circuit plays a role in reward and fear learning, stress responses, contextual eating, and various social behaviors, including aggression and response to social novelty. Consistent with these functions, the LS is often reciprocally associated with regions such as the ventral tegmental area, the dorsal raphe, the amygdala, various subregions of the hippocampus, and many cortical regions. Although SL is known to contain diverse GABAergic cell populations that express combinations of neurotensin, somatostatin, and calbindin but lack parvalbumin, the overall chemoarchitecture of SL is poorly understood. To better understand and characterize cellular composition in LS, we used single nuclear RNA sequencing (snRNA-seq) to create a molecular atlas of LS cell types.

Methods:Here we use the 10X Genomics 3' single cell platform to generate molecularly defined LS cell types using snRNA-seq. For each sample, LS tissues from 2 same-sex virgin mice were pooled and processed together [N = 4 total samples (n = 8 mice, 4 females, 4 males)]. Brains were harvested, frozen and sectioned into two 1 mm coronal brain slices spanning the LS tract along the anteroposterior axis. The LS was dissected from each plate and the nuclei were isolated by the method described by Martelotto et al. developed the "Frankenstein" core isolation protocol. (2020). Samples were sorted on the Bio-Rad S3e Cell Sorter, sorting 9,000 cell nuclei directly onto reverse transcription reagents from the 10x Genomics Single Cell 3' Reagents v3.1 kit. 10x Chromium was performed and the libraries were prepared according to the manufacturer's protocol and then sequenced on an Illumina NovaSeq 6000. FASTQ data generated from the sample libraries were aligned to the mouse genome using Cellranger (version 6.1 ), using the intron inclusion indicator to account for nuclear transcriptome configuration. Using the Bioconductor suite of single cell analysis packages from Amezquita et al. (2021) the call to the kernels was made using empty drops in the raw resource barcode arrays. In particular, we used a sample-based limit for invoking cores because the default limit failed and invoked cores that were approximately 10 times larger than requested. We then performed mitochondrial rate adaptive thresholding using a 3-fold absolute deviation of the median from the median to the threshold and filtered out so-called nuclei from each sample. Feature selection was calculated using deviant residues and the total deviation was used to calculate the 2000 most deviant genes. In this resource space, the PCA was performed according to Townes et al (2019). Using the top 50 PCs, we performed graph-based clustering with k = 20 nearest neighbors, and the walktrap community detection algorithm returned 35 tentative clusters. We grouped based on the expression of mouse orthologs of cell class markers from Tran, Maynard et al. (2021) noted. For the detection of cluster markers, we used the method described in Tran, Maynard et al. (2021) used the described approach to characterize cluster-significant matched strict test markers in addition to cluster-enriched markers. Uniquely identified gene markers expressed by each cluster were examined using data from Allen Brain's Whole Genome In Situ Hybridization (ISH) Atlas to assign clusters to regions by examining the spatial distribution of markers.

Results:We identified 33 groups of cell types, 24 of which are neuronal. Within the neuronal populations, 18 originated from the septum and six from other adjacent regions (the striatum (four), the thalamus (one) and the islets of Calleja (one)). The septal populations were further divided into subgroups and classified. Nine GABAergic groups have been named LS, including a distinct GABAergic population lining the ventricle. Three glutamatergic groups were identified as the medial septum encompassing a small cholinergic population. Three glutamatergic clusters were noted as a mixture of neurons from the dorsocaudal septum, where the tapeworm thecta, the induseum griseum and the septohippocampal nucleus are located. Two GABAergic clusters were noted as wide septal because their clustering markers were not restricted to a previously identified septal subdivision. A glutamatergic group was named triangular septal nucleus. A set of selected genes identified from previous LS chemoarchitecture studies were used to characterize specific groups of LS. These genes included receptors for neuromodulators, such as dopamine, norepinephrine, and serotonin, and receptors for neuropeptides, such as oxytocin, vasopressin, and corticotropin-releasing hormone. We then identified the cellular expression patterns of these markers in our annotated clusters. Finally, we generated an interactive web browser to allow exploration of these data for the neuroscientific community.

Conclusions:Together, these data form a molecular atlas of septal cell types. We describe cell-specific gene expression patterns and identify new types of neuronal LS cells. This feature provides cell-type specific information that will be helpful in understanding the biology of LS and which cell types may underlie LS-mediated behaviors.

Key words:Lateral septum, single-core RNA sequencing, GABA neuron, septum

Disclosure:Nothing to disclose.

Kira Griffiths, Gunjan Batra, Li Tong Low, Emily Palmer, Miguel Renteria, Rashmi Patel, Scott Kollins*

Holmusk, New York, New York, USA

Background:ADHD symptoms can be classified as inattentive (IA) or hyperactive/impulsive (H/A). However, significant heterogeneity in the clinical presentation of ADHD across development and between genders has been reported. Network analysis provides a more detailed understanding of symptom structure compared to traditional factor analysis approaches. Electronic Health Record (EHR) data capture real-world symptom presentation in large, representative cohorts. The current study applied network analysis to real-world symptom data from adults with ADHD. This study aimed to examine and compare ADHD symptom networks in adult men and women.

Methods:Symptoms recorded by mental health professionals as part of the clinical assessment were obtained from an unidentified EHR dataset from 25 US psychiatric systems (WCG Institutional Review Board Ref: WCG-IRB 1-1470336-1). The cohort included adult patients (> 18 years old) diagnosed with ADHD (ICD9/10: 314.00, 314.01, F90.0, F90.1, F90.2, F90.8, and F90.9) and symptom data in the first six months after diagnosis. Symptoms were defined according to the 18 symptoms described in DSM-5. Networks for men and women were constructed separately, with each symptom reflecting a single node within a network. Symptoms were entered as binary variables indicated by their presence or absence in individual patients. Analyzes were performed using R version 4.1.3, Bootstrap 1.5 package and Isingfit v0.3.1 package. Meshes were estimated using the eLASSO method and then visualized. Measures of betweenness, proximity and centrality of force were calculated, in addition to the network diagrams. In psychiatric symptom networks, measures of centrality allow the identification of symptoms of high importance within a network and can therefore highlight key symptoms for intervention.

Results:Data were available for 2398 patients (53% female) diagnosed with ADHD. Networks grouped into H/I and AI symptoms. In adult men, symptoms of hyperactivity/impulsivity form a relatively dense network, whereas symptoms of inattention are less central. The H/I and AI symptom clusters were relatively more widely distributed in females than in males. In terms of severity, the three most important individual symptoms for men and women were two symptoms from the H/I group and one from the AI ​​group. However, these differed by gender, with the strongest symptom associations in men being excessive/inappropriate exercise, mobility and inattention. While in women, the symptoms of sitting still, frequent interruptions and easy distraction showed the greatest strength in the network. Regarding intimacy, the most central symptom was in the AI ​​group for women (does not seem to listen) and in the H/I group for men (difficulty waiting their turn). H/I symptoms were most central to intermediates in both men and women and reflected inappropriate movement.

Conclusions:The grouping of H/A and AI symptoms is generally consistent with current conceptualization of ADHD. Differences in individual symptoms identified as most central to each network provide further evidence that symptoms may vary in terms of clinical relevance for men and women, making the identification, diagnosis and treatment of ADHD common to all, and may affect gender. These different networks may also be important in identifying unique treatment targets for men and women. Furthermore, the general approach to characterizing networks may also be important to more accurately define ADHD symptoms in other subgroups (eg, different racial/ethnic groups, different developmental stages).

Key words:ADHD, gender differences, network analysis

Disclosure:Holmusk: Employees (Own), Holmusk: Shares/Shares (Own)

Jamie Earnest*, Jennie Garcia-Olivares, Brittney Yegla, Vladimir Maletic, Chungping Yu

Supernus Pharmaceuticals Inc., Crownsville, Maryland, United States of America

Background:FDA-approved ADHD treatments are thought to work by increasing dopamine (DA) and norepinephrine (NE) signaling in the brain. The focus on these neurotransmitter systems largely stems from the pharmacology of effective treatments. However, the diversity of symptoms and comorbidities in ADHD, new genetic and imaging studies, and the strongly demonstrated efficacy of viloxazine ER (despite its moderate ability to inhibit norepinephrine transporters (NETs)) suggest that it may be involved in a more complex neuropathology. In a previous microdialysis study, we found that viloxazine increased serotonin (5-HT) in the prefrontal cortex (PFC) in addition to increasing NE and DA. Likewise, an initial in vitro functional activity study suggested that viloxazine may act as a partial agonist at 5-HT2C receptors and as an antagonist at 5-HT7 and 5-HT2B receptors. However, it was unclear to what extent these effects occurred at clinically relevant concentrations. To better understand these serotonergic effects, we initiated a series of experiments to build on this earlier work. Our goals are threefold: 1) Can we confirm and elucidate previously observed serotonergic effects of viloxazine and determine whether they occur at clinically relevant concentrations? 2) Are these effects observed in species whose physiology approaches human?

Methods:In response to Target 1, viloxazine was tested in in vitro binding competition assays for 5-HT2C, 5-HT2A and 5-HT7 receptors using the specific radioligands [3H]mesulergin, [3H]ketanserine and [3H ]- LSD or equivalent reference compounds. An in vivo PK/PD microdialysis study was also performed in Sprague-Dawley rats by administering doses of 1, 3, 10, or 30 mg/kg of viloxazine to determine the relationship between viloxazin concentrations in the interstitial fluid (ISF) and changes in the to-be-determined concentrations of NE, DA, 5-HT and their metabolites in the PFC. In response to Objective 2, a PET imaging study using a radioligand 5-HT2A/2 C agonist, [11 C]CIMBI-36, was performed in anesthetized cynomolgus monkeys to determine the effect of viloxazine on cortical release of endogenous 5-HT and to assess direct binding to 5-HT2C receptors in the choroid plexus.

Animal experiments were performed at Charles River Laboratories (South San Francisco, CA, USA) and Karolinska Institutet Psychiatry Research Center (Stockholm, Sweden) and approved by local animal ethics and welfare committees. The animals were kept according to international standards.

Results:Objective 1: In vitro binding competition assays in cell lines expressing the human isoforms 5-HT2C, 5-HT7 and 5-HT2A confirmed the affinity of viloxazine for these receptors with Ki values ​​of 1.5, 1.9 and 16.3 µM. In addition, the microdialysis study was performed in rats at a dose of 30 mg/kg, where the Cmax of viloxazine in ISF was 3.5 ± 1.6 µM, which is approximately the plasma concentration of free viloxazine (2.1 -3.3 µM) seen in pediatric patients Patients with ADHD receiving viloxazine ER 400 mg/day. At this clinically relevant concentration, viloxazine increased NE levels by up to 558% from baseline and significantly decreased its DHPG metabolite from baseline, confirming NET inhibition. Serotonin levels significantly increased by up to 213% from baseline; however, no significant changes were observed in its 5-HIAA metabolite, showing that serotonergic effects are not due to inhibition of 5-HT reuptake. Objective 2: Administration of viloxazine at 3 mg/kg to non-human primates resulted in a free plasma concentration of 3.9 µM (Cmax), consistent with concentrations measured in pediatric patients with ADHD. At this clinically relevant concentration of viloxazine, changes in [11 C]CIMBI-36 binding potential in the choroid plexus and cortical region were 60% and 25-36%, respectively, indicating that viloxazine binds directly to 5- HT2C receptors can bind in the choroid plexus. and increase endogenous 5-HT levels in cortical regions.

Conclusions:To date, our experiments to further elucidate the potential serotonergic effects of viloxazine have successfully demonstrated that 1) the previously observed in vitro effects of viloxazine on serotonin receptors and the in vivo elevation of serotonin in the PFC of rats are present at clinically relevant and 2) Serotonin modulatory effects in vivo are also observed in non-human primates, suggesting that they can be translated clinically. Overall, it appears that viloxazine can increase serotonin concentrations in cortical regions, including the PFC, at concentrations that have been shown to be therapeutic in pediatric ADHD studies. Data from in vitro receptor studies and PET studies are consistent with viloxazine binding to the 5HT2C receptor.

Key words:viloxazine, ADHD, PET imaging, microdialysis, serotonin

Disclosure:Supernus Pharmaceuticals: Employees (Own), Johnson and Johnson, Alkermes, Merck: Shares/Shares (Own)

Amber Asher*, David Morilak

University of Texas Health Science Center, San Antonio, Texas, USA

Background:Prostate cancer (PC) is the second most common cancer in American men, with 1 in 8 men being diagnosed with PC at some point in their lives. Despite this high prevalence, treatment for PC is effective and the 5-year survival rate exceeds 99%. Unfortunately, however, many cancer survivors experience ongoing cognitive impairment associated with life-saving treatment, and few treatment options are available for these patients to prevent or reverse the impairment. In particular, patients receiving chemotherapy show impairments in working memory, cognitive flexibility, attention and visuospatial memory that can persist after the end of chemotherapy in a phenomenon colloquially known as "chemobrain". Docetaxel (DTX) is a microtubule-stabilizing agent approved for the treatment of advanced-stage CP and has been associated with cognitive impairment in human cancer patients and in studies with healthy rodents. The mechanisms behind the Chemo Brain have yet to be elucidated. Furthermore, the additional factor of cancer pathophysiology is rarely considered in preclinical studies, and the contribution of a peripheral tumor to these impairments is also unknown. Here we use a novel syngeneic mouse PC model to characterize cognitive impairment caused by the interaction of a tumor and DTX. In addition, we examined changes in two circulating pro-inflammatory cytokines, tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) as possible tumor-induced physiological changes that could predispose the brain to DTX.

Methods:Male Copenhagen rats, aged 3 months, were used in this study. To generate the PC model, a small fragment of a tumor grown from syngeneic Dunning R-3327G cells with Copenhagen rats was implanted subcutaneously along the dorsal midline between the scapula and the pelvis. Sham animals received a sham operation. When the tumor became palpable, the animals were treated three times with DTX (4.5 mg/kg/injection; i.p.) or its vehicle (i.p.) for five days, followed by a two-week recovery period. Hippocampus-dependent visuospatial memory and working memory were assessed using the task of locating new objects and spontaneous switching in a Y-maze, respectively. Plasma was collected after behavioral testing and TNFα and IL-6 levels were quantified using commercially available enzyme-linked immunosorbent assays. Tumors were measured every 7 days using digital calipers and tumor volume was calculated.

Results:Tumor-bearing rats showed impaired visuospatial memory regardless of treatment. Elevations in TNFα and IL-6 were observed in the plasma of tumor-bearing mice compared to sham mice, regardless of treatment. Treatment with DTX alone in mice with sham implants also resulted in an increase in plasma IL-6 levels that was still apparent two weeks after discontinuation of treatment.

Conclusions:The presence of a peripheral tumor produced alterations in hippocampus-mediated visuospatial memory and increases in plasma TNFα and IL-6 compared to sham animals. Administration of DTX to mice with dummy implants resulted in minor impairments in hippocampus-dependent behavior, which appeared to be worse in tumor-bearing animals. In peripheral measurements of inflammatory cytokines, DTX treatment in shams resulted in an increase in plasma IL-6 that was evident 2 weeks after the last injection, indicating long-lasting inflammation in shams. TNFα and IL-6 were elevated in vehicle-treated and DTX-treated tumor-bearing mice, despite the fact that tumor volume was significantly reduced in the latter group. Taken together, the presence of a peripheral tumor leads to hippocampus-dependent impairments in cognition and increases plasma TNFα and IL-6, even when effectively treated with DTX. Experiments are underway to investigate more acute changes in cytokine production, as well as changes in blood brain integrity induced by the combination of tumor and DTX.

Key words:Cancer, cognitive impairment, hippocampus, inflammation

Disclosure:Nothing to disclose.

Giannina Descalzi*, Kaitlin Scherer, Paige Reid, James Tang

University of Guelph, Guelph, Canada

Background:Chronic pain is a major risk factor for anxiety and depression, with over sixty percent of people with chronic pain experiencing severe depression and anxiety; significant limitations in physical and social functioning; and underemployment or job loss because of your pain. Tragically, the risk of dying by suicide doubles for people with chronic pain. Current treatment options are woefully inadequate, with less than half of all patients reporting pain relief with current treatments. Neuroimaging studies in humans and rodents indicate that chronic pain corresponds to the reorganization of an emotion-pain circuit in the brain, and there is evidence that the neuroplasticity of the anterior cingulate cortex (ACC) is a critical step in this reorganization. We have previously shown that chronic pain and fear learning increase neuronal excitability and induce similar plasticity-related changes in gene expression in the anterior cingulate cortex of mice. We have recently shown that fear learning requires neuronal astrocyte lactate transport (ANLS) in the dorsal hippocampus and that ANLS is required for associated molecular changes induced by learning, including an increase in gene expression related to plasticity. Here we present data suggesting that ANLS in the ACC may also be involved in neuroplasticity related to chronic pain models in mice.

Methods:Adult male mice were challenged with chronic inflammatory pain modeled by hindpaw injection of complete Freund's adjuvant (CFA). Vehicle injections were used as a control. Pain thresholds were measured 3 hours (h), 24, 72 and 7 days after injury, and ACC samples were collected immediately after the threshold test. Lactate levels were quantified by a colorimetric lactate assay, and Western blot analyzes determined the expression of proteins involved in lactate transport between astrocytes and neurons. Continuous and transient inflammatory pain was modeled by formalin injections in the hind paw, with vehicle injections serving as controls. We used antisense oligonucleotides (AS-ODN) targeting MCT4 monocarboxylate, which is expressed exclusively in astrocytes, to decrease lactate export from astrocytes.

Results:Male mice (n = 10/group) showed a rapid increase in detectable ACC lactate levels three hours after CFA injection compared to vehicle-injected controls. These values ​​returned to baseline one day after injury, but steadily increased thereafter, resulting in significantly higher lactate levels seven days after injury compared to pain-free vehicle-injected control mice. Mice injected with MCT4-AS-ODN into the ACC showed significant reductions in MCT4 protein expression in the ACC 24 hours (hrs) post-injection compared to injections of a nonsense control-encoded ODN. We found that male mice that received intra-ACC MCT4 AS-ODN 24 h before formalin injection showed significantly less pain-related licking behavior in the formalin test compared to the non-coding control, which was obtained by intra-ACC injection of lactate saved 15 minutes before formalin injection (n=9/group).

Conclusions:Our data indicate that astrocyte-neuron coupling is critically involved during the early stages of chronic pain development. Furthermore, our data indicate that disruption of neuronal astrocyte lactate transport in the ACC blocks pain persistence in male mice.

Key words:Astrocytic, chronic pain, astrocytic-neuronal lactate transport

Disclosure:Nothing to disclose.

Thomas Prevot*, Ashley Bernardo, Michael Marcotte, Kayla Wong, Prithu Mondal, James Cook, Etienne Sibille

University of Toronto, Center for Addiction and Mental Health, Toronto, Canada

Background:Several psychiatric, stress-related, and neurodegenerative disorders demonstrate reduced GABA/somatostatin (SST) signaling. SST +  interneurons from the cortical layers and the hippocampus exert dendritic inhibition on excitatory neurons, primarily through α5-containing GABA A receptors (α5-GABAAR). Our group showed that positive allosteric modulation for α5 helps to alleviate working memory deficits and reverse neuronal atrophy in aged and stressed mice. Here, we intend to confirm our previous results in an age-independent cohort and evaluate the behavioral and neurotrophic effects of an α5-positive allosteric modulator (α5-PAM) in animal models of other diseases associated with reduced GABAergic function, such as. B. chronic stress, investigate further and β-amyloid load.

Methods:Three studies with ~N=12 mice/group, 50% female, are presented: 1) Young C57BL6 exposed to unpredictable chronic moderate stress (UCMS) to provoke cognitive deficits. 2) 20-month C57BL6 with pre-existing cognitive impairment. 3) 5xFAD transgenic mice with amyloid-related progressive cognitive impairment. All studies evaluated the effectiveness of chronic administration of α5-PAM (30 mg/kg, orally, for 4 weeks) in rescuing cognitive deficits in 3 domains. Working memory was assessed in a Y-maze switching task, spatial learning and memory in the water maze, and cognitive flexibility in a set switching experiment. Brains were then stained using the Golgi-Cox technique (n=4 brains/group; 8 cells/brain), sectioned and mounted for quantification of dendritic length and spinal column density in the prefrontal cortex and hippocampus (NeuroLucida). All laboratory animal studies and techniques were performed in accordance with the Ontario Research Animals Act (RSO 1990, Chapter A.22) and the Canadian Animal Care Council (CCAC) and approved by the Committee of CAMH Animal Care.

Results:Chronic treatment in stressed, elderly or 5xFAD mice reversed cognitive deficits in all domains of each model (ps < 0.01) with a potent effect on working memory. Chronic treatment also consistently reversed UCMS, age- or amyloid-induced dendritic shrinkage, and spine loss in apical and basal dendrites (p < 0.001 in PFC and CA1).

Conclusions:Taken together, the presented results support that selective targeting of α5-containing GABAA receptors overcomes cognitive deficits associated with chronic stress, aging, or amyloid in chronic treatment and reverses impairments in neuronal morphology. Taken together, the data indicate a positive impact on the symptomatic and disease-modifying dimensions and underscore the high therapeutic potential of α5-PAMs.

Key words:Cognition, dendritic spine, animal models, positive allosteric modulator α5-GABAA

Disclosure:Nothing to disclose.

Ryan Terry-Lorenzo*, Daniel Albrecht, Satjit Brar, Graham Searle, Frans Van Den Berg, Ilan Rabiner, Dietrich Haubenberger

Neurocrine Biosciences, Inc., San Diego, California, USA

Background:Valbenazine, a potent, selective, orally active inhibitor of vesicular monoamine transporter 2 (VMAT2), is approved by the U.S. Food and Drug Administration for the treatment of tardive dyskinesia (TD) at low doses of 40 to 80 mg once daily. day. By inhibiting VMAT2, valbenazine disrupts the packaging of monoamines into synaptic vesicles, which subsequently decreases the release of monoamines, including dopamine, into the synaptic cleft. Dopamine reduction is believed to underlie the effectiveness of valbenazine in the treatment of TD and other hyperkinetic movement disorders. The reduction in synaptic dopamine also justifies the potential benefit of valbenazine in the treatment of psychosis. However, to the best of our knowledge, no dopamine reduction by valbenazine or any other VMAT2 inhibitor has been demonstrated in humans. The aim of this study was to investigate the change in synaptic dopamine following administration of valbenazine using positron emission tomography (PET) in healthy human volunteers.

Methods:Imaging and tolerability data in this adaptive study were collected and analyzed in cohorts of 2 to 4 healthy volunteers. For each scan, participants received an injection of the D2/D3 dopamine receptor agonist radioligand [11 C]-PHNO, followed by 90 minutes of data collection with Siemens Biograph PET/CT. For post-valbenazine scans, participants received an oral dose of valbenazine 6-8 hours before [11C]-PHNO administration, and PET images were acquired around the time of peak plasma valbenazine concentrations. The connection potential relative to non-displaceable connection (BPND) in the putamen, caudate and ventral striatum was used as the primary endpoint. The cerebellum was used as a reference region to estimate the regional BPND. A decrease in synaptic dopamine after valbenazine administration corresponded to an increase in [11 C]-PHNO-BPND compared to baseline (ΔBPND). Plasma concentrations of valbenazine and (+)-α-dTBZ (dihydrotetrabenazine), the active metabolite of valbenazine, were measured at the beginning and end of each post-valbenazine PET scan. Mean plasma concentration of (+)-α-dTBZ (Cave) was compared with each subject's ΔBPND to provide an exposure response curve.

Results:So far, 9 participants (5 men, 4 women) have completed the test. These participants received between 40-160 mg of valbenazine, resulting in plasma (+)-α-dTBZ Cave between approximately 10-60 ng/ml. Eight participants showed valbenazine-induced dose-dependent increases in [11 C]-PHNO ΔBPND (21-44%). Higher exposures to (+)-α-dTBZ from higher doses of valbenazine resulted in a higher ΔBPND, showing a monotonic exposure-response curve. Adverse events in this study were consistent with the known safety and tolerability profile of valbenazine as reported in the TD clinical studies.

Conclusions:Valbenazine appears to decrease synaptic dopamine in a dose- and concentration-dependent manner, as indicated by an increase in [11 C]-PHNO ΔBPND. The approximately 20-40% increase in [11 C]PHNOΔBPND seen in this study is similar to the [11 C]PHNOΔBPND seen previously after treatment with a dopamine-reducing tyrosine hydroxylase inhibitor (Caravaggio et al, Neuropsychopharmacology 2014;39:2769 ) . 🇧🇷 Therefore, biologically significant reductions in dopamine have been observed in humans at pharmacological and therapeutic doses of valbenazine. These data will allow future exploration of the relationship between VMAT2 inhibition and the potential treatment of other central nervous system disorders.

Key words:Positron Emission Tomography (PET), VMAT2, biomarkers

Disclosure:Neurocrine Biosciences, Inc.: Employees (themselves)

Connor Haggarty*, Conor Murray, Royce Lee, Ilaria Tare, Harriet of Wit

University of Chicago, Chicago, Illinois, United States

Background:Methamphetamine (MA) is a stimulant drug characterized by heightened feelings of arousal, cardiovascular effects, and changes in electrophysiological function. In particular, previous studies indicate that stimulants decrease alpha potency in EEG studies, consistent with increased wakefulness. In the present study, the subjective, physiological, and cortical effects of acute MA (10 and 20 mg) in healthy volunteers were measured to examine relationships between its effects on alpha potency and other measures.

Methods:Healthy volunteers (N=29) aged between 18 and 35 years participated in a double-blind, intra-subject design in which they received placebo, 10 mg, and 20 mg MA in 4-hour sessions at least four days apart. During the sessions, they completed subjective effects questionnaires and measurements of heart rate and blood pressure were taken. One hour after capsule ingestion, resting EEG measurements were taken to determine power in five frequency bands with eyes open. Data were analyzed from electrodes representing the network in default mode.

Results:MA (10 and 20 mg) dose-dependent increase in drug and effect ratings and increase in mean arterial pressure compared with placebo. MA (10 and 20 mg) significantly decreased linear alpha power without significantly affecting other frequencies. The decrease in alpha potency after MA (20 mg) was significantly correlated with an increase in vitality but was not correlated with an increase in blood pressure.

Conclusions:These data support the association between increased feelings of arousal and decreased alpha frequency performance. Single doses of MA increased subjective arousal and blood pressure and decreased alpha production, but only the subjective effects were related to the EEG measurement. This supports the measurement of EEG as an index of cortical processing associated with acute drug effects.

Key words:Methamphetamine, EEG, subjective effects

Disclosure:Nothing to disclose.

Andrew Olagunju*, Jeffrey Wang

McMaster University, Hamilton, Canada

Background:There are positive benefits and contributions of ethnicity and race to health and well-being (eg through personal/collective identity). However, belonging to a racial or ethnic group has also been associated with health disadvantages and negative perceptions: racism, stereotypes and discrimination. A good understanding of ethnic/racial classifications and groups in the specific practice setting is beneficial for culture-sensitive clinical practice and psychopharmacological decisions. With this in mind, we undertook this study to review and describe the current literature on ethnic and racial issues in the practice of clinical psychopharmacology.

Methods:This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews guide and the Meta-Analyses for Scoping Reviews extension. We searched large databases, including Pubmed/Medline, PsycINFO, Embase, CINAHL, and Web of Science, for eligible studies published to date. The search string combined MeSH terms for clinical psychopharmacology, race, and ethnicity. This was complemented by a snowball search for references in relevant studies and, where appropriate, contacting authors for publication. All included studies will be assessed using the National Institutes of Health's study quality assessment tools based on study designs. Data extraction and quality assessment are performed for the included studies.

Results:A total of 57 reports are identified for title and summary selection. Next, data extraction and analysis takes place.

Conclusions:Through this review, we hope to highlight issues relevant to the promotion of racial diversity and equity in psychopharmacological practice and education. Integration of ethnic correspondences and appropriate racial/ethnic representation in study participants participating in psychotropic clinical trials and other research activities is addressed.

Key words:Racial/Ethnic Differences, Clinical Psychiatry, Psychopharmacology

Disclosure:Nothing to disclose.

Shaista Chaudhary, Dipak Sarkar*

Rutgers University, New Brunswick, New Jersey, USA

Background:The impact of alcohol consumption during pregnancy can alter the phenotype of the offspring and have devastating and lasting consequences, such as: B. Central nervous system disorders. However, it is not known whether fetal alcohol exposure promotes the physiological and biochemical features of Alzheimer's disease during aging.

Methods:We used a human-like mouse model established in the first and second trimesters of fetal alcohol exposure, comprising feeding a liquid diet containing ethanol at a concentration of 6.7% v/v, or feeding the partner a liquid diet isocaloric or ad libitum feeding of rat chow from the 7th to the 21st day of gestation in isogenic Fischer 344 (F344) rats. Pups were weaned on day 21 after birth and housed by sex and used for behavioral and biochemical studies at approximately 12 months of age. Only one male and one female pup from a litter of rats were used in each experimental group. Six rat pups were allocated to each group. All animal care and procedures were approved by the Rutgers Institutional Animal Care and Facilities Committee and were in accordance with National Institutes of Health guidelines. We measured learning and memory behavior using the Morris Water Maze Test. As cognitive and memory disorders are often associated with cholinergic dysfunction and acetylcholinesterase (AChE) activity, we examined AChE activity in the cerebral cortex and hippocampus regions of the brain. Using Western blot assays, we measured levels of several biochemical markers of Alzheimer's disease, including β-amyloid (Aβ) and Aβ1-42 proteins, total and phosphorylated tau proteins, β-site amyloid precursor protein (APP), which cleaves enzyme 1 (BACE1) and UNC5C netrin receptor proteins in cerebral cortex and hippocampus regions of the brain. Data were analyzed statistically using a two-way analysis of variance (ANOVA) followed by Bonferroni's multiple comparison test to determine time-dependent changes between groups. Multiple group comparisons at a single time point were performed using one-way ANOVA followed by Tukey's post-squat test. A p-value less than 0.05 was considered significant.

Results:Measurement of cognitive and memory functions using the Morris water maze test showed a greater escape latency in alcohol-exposed fetal rats (alcohol-fed pups) in male and female rats than in control rats (both pups fed ad libitum and those fed in pairs were fed). at 12 months of age. Furthermore, rats exposed to fetal alcohol had a shorter time to escape the platform quadrant, indicating significant memory impairment in these animals. The magnitude of alcohol's effects on fetal learning and memory appears to be similar in male and female offspring. These animals also showed increased activity of AChE, Aβ and Aβ1-42 proteins, hyperphosphorylated tau proteins, BACE1 and UNC5C in the cerebral cortex and hippocampus regions of the brain during aging. The magnitude of enzymatic and protein responses to AEDs were also similar in male and female offspring.

Conclusions:Taken together, these results provide evidence that fetal alcohol exposure increases the expression of some of the biochemical and behavioral phenotypes of Alzheimer's disease during aging.

Key words:Fetal Alcohol Spectrum Disorder, Neurodevelopmental Disorders, Alzheimer's

Disclosure:Nothing to disclose.

Mario Serrano-Sosa, Philip Tubiolo, Thomas Hagan, John Williams, Chuan Huang, Jared Van Snellenberg*

Stony Brook University Renaissance School of Medicine, Stony Brook, Nova York, EUA

Background:Working memory (WM) is a key cognitive domain and is disrupted in many psychiatric and neurological disorders. While a bilateral network of brain regions including the dorsolateral prefrontal cortex (DLPFC), presupplementary motor area (pre-SMA) and intraparietal sulcus (IPS) are reliably activated during WM tasks, little is known about how activation in these regions is related to behavior. WM capability measures. A major challenge is the high dimensionality of fMRI data, which generally limits analyzes to single-voxel univariate linear mass model approaches or similar.

However, recent work in computer vision has shown that some convolutional neural networks (CNN) work well in classifying and predicting images. CNNs learn the hierarchical features of images at different levels of abstraction in a non-linear and data-driven way. While deep learning algorithms are often "black boxes", network backpropagation can be used within a CNN to determine which image positions are most important to network performance. These "highlight maps" can be generated from a trained network for each input and reflect the gradient of the output prediction, indicating which image positions affect the performance of the network the most.

Here, we use data from a Human Connectome Project (HCP) n-back WM task and a CNN to identify cortical regions whose activation during WM predicts WM performance in a non-linear, data-driven way from the whole brain. To the best of our knowledge, this work reflects the first use of recent developments in computer vision to identify brain regions whose activity predicts performance on cognitive tasks from fMRI data.

Methods:We used n-back task data from 419 subjects (male and female) from version 1200 of the HCP, with only subjects with 3T MR data, 100% WM task completion, no significant QC issues (A, B, or C issues of according to the HCP documentation) and data recorded in MSMAll. We use only one subject from each kinship set to prevent CNN from learning traits shared by genetically related individuals.

Cortical surface data for 2-back-0-back contrast (all stimulus conditions) were extracted from CIFTI images and plotted on a flattened surface. The left and right hemispheres were concatenated to form a single 2D image for CNN input. CNN used a U-net architecture with 4 convolutional blocks followed by 3 fully connected layers. The network was trained to predict the percentage of correct results in the 2-back condition for each participant. We used 5-way cross-validation to obtain blind predictions and saliency maps for each subject: 5 independent networks were trained, each with 335 subjects for training and 84 subjects for validation. Highlight maps were generated by backpropagation using the SmoothGrad algorithm to reduce spatial noise. To compare CNN's performance, we also trained a kernel ridge regression (KRR) model.

Salience maps (limited between 0 and 1) were centered on the mean of each subject to allow valid testing of null hypotheses. The maps were then used to identify regions of significantly above-average emphasis by testing the null hypothesis that emphasis < =0 using Permutation Linear Models (PALM) at P <0.025, corrected by FWE. The highlight cards were then z-scored and subjected to principal component analysis and correlated with task performance. Previous analyzes used dummy regressors across all 5 holdout sets to remove systematic differences in emphasis across the 5 independent CNNs.

Results:CNN outperformed KRR on all metrics evaluated (R2, MAE, MAPE, and RMSE) with an R2 of 0.389 (0.373 for KRR). We observed a significantly above average increase in the bilateral ventrolateral PFC, left premotor cortex, and several regions of the default mode network (DMN), including the bilateral anterior medial PFC (am PFC), the precuneus, and retrosplenial cingulate cortex, the temporal parietal junction, the temporal pole, and the left mediotemporal gyrus. Most of the left and right DLPFCs and the bilateral intraparietal sulcus did not show above average prominence.

Four principal components (1, 2, 3, and 9) were significantly associated with task performance, with PC1 showing the strongest relationship (r = -0.54). Strains in PC1 showed that strong task performance was associated with high prominence of amPFC, medial temporal lobe, left medial temporal gyrus, and temporal pole, and low prominence of bilateral DLPFC, IPS, and pre-SMA.

Conclusions:These results indicate that interpretable deep learning using CNNs and salience maps holds promise as a new means of obtaining information about brain regions whose activation is associated with task completion. Contrary to expectations, our results suggest that the extent of DMN deactivation contains more information about WM task performance than DLPFC, IPS, or pre-SMA activation. The PCA results further suggest that activation in these latter regions predicts performance, but only in low-performing individuals. As higher activation in these regions was associated with high performance, this suggests that only low levels of activation predict poor performance; Instead, when activation on that network reaches a certain level, CNN looks for deactivation in amPFC and other DMN regions to identify top performers. While this approach is still in its infancy, it has clear potential to yield new insights into how the human brain serves higher-order cognition in health and disease.

Key words:fMRI-Arbeitsgedächtnis, Convolutional Neural Network (CNN), Human Connectome Project (HCP), Multivariate Ansätze, Deep Learning

Disclosure:Nothing to disclose.

Sophia Beas*, Isbah Khan, Claire Gao, Emma McDonald, Alison Bashford, Shakira Rodriguez-Gonzalez, Mario Penzo

University of Alabama at Birmingham, Birmingham, Alabama, United States

Background:Previous research has focused mainly on studying the contribution of the mesolimbic dopaminergic system to these processes. However, the role played by glutamatergic inputs in the NAc in controlling motivation is much less clear. The paraventricular nucleus of the thalamus (PVT), a brain region that integrates bottom-up interoceptive signals with top-down cortical information, sends robust glutamatergic projections to the NAc. We have recently identified two distinct large subpopulations of neurons in the PVT (Type1PVT and Type2PVT) that differ in their genetic identity, connectivity features, and functionality. These subpopulations send different projections to the NAc, raising the possibility that type1PVT and type2PVT neurons likely enable different but complementary aspects of motivated behavior. However, very little is known about the role of thalamic inputs to the NAc in mediating motivational processes.

Methods:Here, we trained diet-restricted male and female mice (n = 6 - 8) to perform linear foraging in the lane. In this task, rats are trained to run from a trigger zone to a reward zone in the maze to collect a food reward (Secure Strawberry). Using calcium bulk imaging and fiber photometry, we examined the in vivo dynamics of Type1PVT (using Drd2-Cre mice and Cre-dependent GCaMP6s) and Type2PVT (using Drd2-Cre mice and a CreOFFGCaMP6f) of parallel thalamo-striatal pathways while mice performed the linear foraging task.

Results:Our results showed that the reward approach was associated with a significant increase in GCaMP fluorescence in the type1PVT NAc pathway. This increase in fluorescence was quantified using the area under the curve, which indicates a significant increase in activity in this pathway compared to baseline activity (t(18) = 4.6, p < 0.01) and compared to controls injected with GFP (t(18 ) = 4.6, p < 0.01) 18) = 4.6, p < 0.01). Furthermore, we found that Type1PVT-NAc signaling activity varies with aspects of motivation such as behavioral strength and levels of satiety. In contrast, 2PVT-type NAc neurons exhibited opposite in vivo dynamics and were not sensitive to motivational variables, suggesting that this pathway may be involved in regulating other aspects of goal-directed behavior.

Conclusions:Taken together, the results collected in this study demonstrate a novel dissociation between the Type1PVT-NAc and Type2PVT-NAc signaling pathways and identify a specific neuronal subpopulation of PVT that signals motivational states.

Key words:Motivation, paraventricular thalamic nucleus, nucleus accumbens

Disclosure:Nothing to disclose.

Sofiya Hupalo*, Chloe Jordan, Terri Bowen, Keri Martinowich, William Carlezon, Tony George

National Institute of Mental Health, National Institutes of Health, North Bethesda, Maryland, USA

Background:The NPP participates in special projects that provide information about the journal's role and support outreach efforts to promote researchers in the areas represented by the NPP and ACNP. In this report, we describe recent activities undertaken by the NPP Special Projects Team to improve the rigor and transparency of clinical trial research and create opportunities for early career researchers to publish in NPP.

Methods:To examine the rigor and transparency of clinical research published in the NPP, we examined the frequency with which authors provide CONSORT (Consolidated Standards of Trial Reporting) documents during the manuscript submission process. CONSORT documents report experimental details, such as B. how the clinical trial was designed, analyzed, and interpreted, and describe the evolution of participants throughout the trial. We track NPP manuscript submissions to capture the number of clinical trial reports submitted and the proportion of submissions that provide complete CONSORT materials.

To further the careers of researchers in the field of neuropsychopharmacology, NPP launched the Early Career Commentary in October 2021 for interns and early-stage researchers to share their scientific knowledge and insights. Consultations are required prior to submission, which will be reviewed by the NPP Special Projects Team and Editorial Board. Priority will be given to consultations that focus on emerging and current issues (eg scientific, social, political, equity) of broad interest and importance to the NPP and ACNP community. Selected requests will be invited to proceed with submission and undergo a standard NPP peer review. The Special Projects Team invited the authors of each early career commentator to participate in NPP's Meet the Author interview series. These interviews give authors the opportunity to deepen their commentary and discuss their research and career goals. Recorded interviews are posted on the NPP YouTube channel and shared on Twitter.

Results:Clinical Trial Submissions:

In 2020, NPP received 140 manuscript submissions that the submitting author identified as a clinical trial. Only 70 (50%) of these submissions contained complete CONSORT documents. When journal staff followed up with corresponding authors of the 70 submissions that did not contain full CONSORT articles, 14 authors requested a waiver and 5 withdrew their submission. Ongoing monitoring of clinical trial manuscripts submitted in 2022 shows a similar non-compliance rate (~55%) when full CONSORT documentation is provided on first submission.

Early Race Feedback: Since launch, the NPP has received 36 pre-delivery requests for early race feedback. Of these submissions, 7 were ineligible because one or more of the authors did not have initial investigator status. In addition, NPP considered all submissions as matters for invited review prior to submission, unless the submission was withdrawn by the authors. To date, NPP has invited 4 groups to write a career start commentary and another 3 groups to write a guest perspective or review an article based on the proposed topic. Two commentaries about the beginning of the career and an article about the perspectives were published. Overall, these manuscripts were accessed 7,162 times, with Altmetric online attention scores ranging between the 85th and 97th percentiles.

Conclusions:To improve transparency and accountability in clinical trial reports published in NPP, the journal is implementing changes to the manuscript submission process. Text describing a clinical trial definition is now included directly on the submission page with links to information about those definitions. Submitting authors must now confirm that their manuscripts meet the clinical trial definition and ensure that the submission includes CONSORT documents and the clinical trial registration number. These changes will improve the speed and rigor of peer review, improve transparency in clinical trial reporting methodology, and increase the impact of work published in the NPP.

The Early Career Commentary was created to provide a place for early career researchers to share ideas and perspectives independently of mentors or key contributors. NPP received many advance requests and selected additional topics for guest comments and insights articles. Articles resulting from this initiative have been widely read and shared on social media, proving that this is a successful approach to nurturing and supporting young scientists in the NPP and ACNP community.

Key words:Clinical study, clinical study methodology, career development

Disclosure:Nothing to disclose.

Ehsan Moazen-Zadeh*, Alexandra Chisholm, Keren Bachi, Yasmin Hurd

Icahn School of Medicine at Mount Sinai, New York, New York, United States of America

Background:Cannabidiol (CBD) has gained exponential attention in research and clinical applications as a potential treatment for various neuropsychiatric and general medical conditions. Today, many CBD-based formulations are under development with the goal of gaining FDA approval, and several unapproved CBD supplements are available without a prescription. However, many questions raised by doctors, researchers and consumers of CBD products are usually related to dosage and administration. One of the main challenges that prevented quantitative aggregation of evidence in previous reviews of CBD pharmacokinetic (PK) studies was the different units and scales for reporting results. Our aim was to provide an up-to-date systematic review of the available evidence on the pharmacokinetics of CBD; provide comparable values ​​of pharmacokinetic parameters from different studies on the same scale; Demonstration of patterns of results based on CBD dose and route of administration; and examine the simultaneous impact of different factors on PK outcomes using meta-regression models.

Methods:This systematic review and meta-regression analysis was previously registered (PROSPERO: CRD42021269857). We systematically searched Medline, Embase, PsychInfo, and the Web of Science Core Collection as of September 19, 2021. Studies of CBD (CBD alone or in combination with THC) in healthy adults were included if they reported at least one of the pharmacokinetic parameters of interest. 🇧🇷 🇧🇷 in serum or plasma, including: time from drug administration to peak plasma/serum CBD concentration (Tmax), maximum plasma/serum CBD concentration (Cmax), area under the serum/plasma concentration curve plotted against to the time from drug administration to a specific time point, typically the end of the PK session (AUC0-t), extrapolation of AUC0-t to the infinite time point (AUC0-inf), and the time until the plasma concentration of the drug is reduced by 50% (T1/2). Studies in patient populations or co-administration of CBD with other drugs were excluded. The National Heart, Lung, and Blood Institute quality assessment tool was used for before and after studies with no control group. A multivariate meta-regression analysis with random effects (alpha = 0.05) was performed with hierarchical models of different factors as independent variables and pharmacokinetic parameters as dependent outcomes.

Results:A total of 97 study arms from 35 studies were included; 26 test arms were qualitatively "good", 56 "fair" and 15 "poor". Six arms used inhaled CBD, 29 orally, 61 orally and 1 intravenously. CBD formulations can be found in nanotechnology (n = 13), oil-based (n = 19), alcohol-based (n = 10), water-based (n = 4), Sativex (n = 17 ) and Epidiolex (n = 21). In single-dose studies, CBD doses ranged from 2 to 20 mg by inhalation, 5 to 50 mg orally, and 0.42 to 6,000 mg orally. Sixty experimental arms had only male participants or more males than females. The duration of the PK session was between 4h-164h. In metaregression models, a higher dose of CBD was consistently associated with higher Cmax, AUC0-t, and AUC0-inf in all models (p-value < 0.001). Compared with oral administration, oral administration was associated with lower Cmax, AUC0-t and AUC0-inf (p-value between 0.001 and 0.007). Fasting was associated with higher Cmax and AUC0-t compared with fasting (p-value <0.001). A higher proportion of female participants was associated with lower Tmax for oral administration and higher Cmax and T1/2 for both oral and buccal administration (p-value between 0.001 and 0.023). Longer study duration was associated with higher AUC0-inf and T1/2 in all models (p-value < 0.001). The highest percentage of variability in the data that can be explained by a model (R2) was 84% ​​for Tmax, 53% for Cmax, 55% for AUC0-t, 54% for AUC0-inf, and 92% for T1/2.

Conclusions:When examining how different factors can affect the pharmacokinetic results of CBD, food intake while using CBD, female gender, and oral administration were all associated with increased bioavailability. Recommendations for future research would mainly be related to conducting initial systematic studies to elucidate the effects of biological sex, PK session duration and different formulations in individual multi-arm studies. With the growing number of CBD supplements on the market and their potential use in clinical practice, it would also be beneficial if more studies examined CBD dosages in the ranges currently used clinically. Finally, reporting PK parameters on arithmetic and geometric scales would support cross-study comparisons, knowledge aggregation, and reproducibility.

Key words:Cannabidiol, population pharmacokinetics, serum levels, therapeutic drug monitoring

Disclosure:Nothing to disclose.

Jacob Beierle, Bryan McKiver, Arthur Vanvalkenburg, Emily Yao, Jared Mann, Binh-Minh Nguyen, Kayla Richardson, William Johnson, Imad Damaj, Camron Bryant*

Boston University School of Medicine, Boston, Massachusetts, USA

Background:Chemotherapy-induced peripheral neuropathy (CIPN) is an inherited side effect of cancer therapy, although the genetic basis is largely unknown. (PAC) exerts antitumor effects by stabilizing microtubules and arresting cell division and is associated with CIPN in 60-70% of patients, causing deafness, hypersensitivity to cold, and allodynia. Human genetic variants have been associated with CIPN within/near genes associated with cytoskeleton, neurodevelopment and pharmacokinetics. Discovery-based genetics in rodents offers a powerful complementary approach to discovering new genetic and biological insights into CIPN with the aim of improving chemotherapeutic profiles. Genetic crosses in closely related rodent substrains (Reduced Complexity Crosses; RCC) allow rapid identification of causative genes/variants underlying complex traits such as CIPN and offer >2 orders of magnitude reduction in the number of segregating variants within a locus and Providing 2 isogenic background quasi edits/validations for necessity and sufficiency of causal variants. Our objective was to identify the differences of the C57BL/6 substrain in the traits of the CIPN model, perform quantitative trait locus mapping (QTL) of behavior and gene expression, and perform transcriptome analysis of PAC Tx. We then identify candidate genes and downstream biological signaling pathways associated with features of the CIPN model.

Methods:We evaluated the behavior of the CIPN model for 1 month in substrains of C57BL/6J (J) versus C57BL/6NCrl (NCrl) mice after treatment with paclitaxel (PAC: 2 mg/kg, every 48 h, 4x) versus vehicle (VEH: 1:1:18: ethanol, kaoliphore, water), including hindlimb mechanical hypersensitivity (von Frey), hindlimb hypersensitivity to cold (acetone test), dorsal caudal nerve conductance, sucrose preference, and tactile hyposensitivity (test). hind paw plantar surface adhesive). After identifying the differences between the substrains, we performed an F2 reciprocal cross and phenotyped 182-206 F2 mice (½ HEV-Tx, ½ PAC-Tx). Genotyping was performed using the miniMUGA DNA array, distinguishing >200 J vs NCrl genetic markers. QTL mapping was performed on R/qtl in 182-206 F2 mice using Hayley-Knott regression (1000 perm) to determine significance thresholds. Credible Bayesian intervals included confidence intervals. Treatment (Tx) was included as an interactive covariate and gender and cohort as additive covariates. RNA sequencing of J and NCrl was performed in dorsal root ganglia (DRG), spinal cord (SC) and periaqueductal gray matter (PAG) using poly-A selected RNA. We used Illumina Nova-Seq with 100 bp paired-end reads and a throughput of >30 million paired-end reads per sample.

Results:We identified robust differences between inbred mouse substrains in CIPN model characteristics between NCrl and J, with J mice showing robust hypersensitivity to mechanical stimulation and hypersensitivity to cold after PAC Tx. QTL mapping in an F2-RCC identified a large QTL in Chr.1 mediating PAC-induced mechanical hypersensitivity on day (D)7 (LOD=7.7; p<0.001; Chr.1: peak 69 Mb :; Bayes: 47-76 Mb ) and a QTL trend in Chr. 14 on Day 15 which mediates cold hypersensitivity (LOD = 4.4; p = 0.095; Chr.14: peak: 124 Mb; Bayes: 23 -125 Mb).

For QTL chr.1 mechanical hypersensitivity, there are 2 compelling causative candidate genes with coding variants, including Abca12 (junction site, chr1: 71 Mb; a gene encoding a known efflux transporter for PAC) and Bmpr2 (chr. 1: chr.1: 60 Mb; Bone Morphogenic Protein Receptor 2, Missense). Differential gene expression analysis of parental substrains via RNA-seq within the chr.1 QTL interval identified a substrain x treatment interaction in Abca12 expression in SC (p = 0.02; J > NCrl). In contrast, neither RNA-Seq nor protein analysis identified differences in Bmpr2 transcript levels (DRG, SC, PAG), BMPR2 protein levels (DRG), or the downstream signaling target SMAD 1/5/9 (expression and phosphorylation of the DRG protein). 🇧🇷 For the QTL interval Chr.14 for cold hypersensitivity, we identified two candidate genes with missense mutations, including Abcc4 (Chr.14: 119 Mb) and Nalcn (Chr.14: 124 Mb). Abcc4 encodes an efflux transporter that transports chemotherapy drugs to affect toxicity, and Nalcn (non-selective, Na+ leak channel) encodes a voltage-gated Na+ channel implicated in chronic pain and mapped to toxicity in Drosophila a be determined.

To identify PAC-modulated biological signaling pathways in the CIPN-responsive J substrain at D7 (chr.1 QTL), accumulation analysis identified GO accumulation terms (p<0.01; adjusted<0.2) containing receptors of growth factor, insulin-like signaling, epithelial morphogenesis, cohesion of centromeric sister chromatids and elastic fibers (top in DRG) and tyrosine degradation process (bottom in DRG). For SC, GO terms included skeletal muscle thin filament arrangement, skeletal muscle hypertrophy, muscle stretch perception or response, skeletal myofibril arrangement, muscle filament sliding, myotube cell development, and muscle tissue morphogenesis (above in SC).

Conclusions:We identified distinct genetic loci for PAC-induced mechanical hypersensitivity and cold hypersensitivity. These loci contain variant/candidate genes involved in pharmacokinetics (transport), pain/inflammatory signaling pathways, and ion channels associated with pain processing. Ongoing studies aim to identify additional functional evidence that would implicate a specific gene or variant prior to gene editing and causal validation studies.

Key words:Nociception, hyperalgesia, chemotherapy-induced peripheral neuropathy, pharmacokinetics, allodynia

Disclosure:Nothing to disclose.

Mark Urban*, Elizabeth Dugan, Katelyn Buban, Jennifer Hagedorn, Sarah A. Woller, Smriti Iyengar, Taleen Hanania

PsychoGenics, Inc., Paramus, NJ, United States

Background:The National Institutes of Health Preclinical Pain Trial Platform (PSPP) program to help end long-term addictionSM or NIH HEAL InitiativeSM aims to accelerate the discovery and development of new therapies for pain, non-opioid pain, and not addictive. Through the HEAL initiative, the NIH is collaborating with PsychoGenics, Inc. to evaluate and profile new drugs in vitro and in vivo, including small molecules, biologics, natural products and devices. Active ingredients are tested in vivo in rat pain models for efficacy and in additional tests to investigate possible adverse effects and liability for abuse. PSPP program efforts also focus on characterizing and optimizing disease-specific pain models to test selected benefits and provide additional support for specific pain indications. Here we describe one such effort to characterize and validate osteoarthritis pain models in rats, including monoiodoacetate (MIA) and medial meniscal tear (MMT) models.

Methods:Adult male and female Sprague-Dawley rats (n = 10/group, each sex) were used in these studies. For the MIA model, MIA (0.3-4.5 mg) was injected intra-articularly into the knee joint of the left hind limb. For the medial meniscal tear (MMT) model, the rats underwent surgery in which the medial collateral ligament was cut to reflect the meniscus on the femur, and then the meniscus was cut at its narrowest point to simulate a tear. . Behavioral pain outcomes included hindlimb mechanical allodynia, knee mechanical allodynia, weight-bearing deficits, and gait changes. Behavioral pain phenotype was assessed in these studies 4 to 6 weeks after osteoarthritis induction. Pharmacology was studied by examining the effects of reference analgesics morphine sulfate (3 mg/kg), ketoprofen (6 mg/kg) and duloxetine (60 mg/kg) after single and repeated administration at the first and penultimate time points of induction were examined. osteoarthritis, likely representing early and advanced stages of the disease.

Data were analyzed by two-way repeated measures ANOVA with post hoc Bonferroni or Dunnett test where appropriate. Effects p < 0.05 were considered statistically significant. Power analysis and effect size were determined using SAS/STAT, and the appropriate sample size was based on a power score of 0.8 to ensure adequate power for F-tests for bidirectional interactions.

Results:Intra-articular injection of MIA (0.3-4.5 mg) into the knee joint of the hindpaw produced unilateral hindpaw mechanical allodynia in male and female rats that was maximal at week 2. Allodynia was observed in unilateral hindpaw mechanics. knee joint to pinching and squeezing stimuli in female rats, but not male rats, at week 2. Weight-bearing deficits associated with the affected hind limbs were small in static weight-bearing measurements but pronounced in dynamic weight-bearing measurements with maximal effects, seen at week 1. In male rats, weight-bearing deficits remained stable throughout the period. Experimental period through week 6, while weight-bearing deficits were observed in female rats at weeks 1 and 2 and were no longer evident at weeks 4 1 and 2. In the MMT model, male rats that received MMT surgery showed unilateral mechanical allodynia of maximum hindpaw at week 3, while no change in hindpaw tactile sensitivity was observed in female rats. Knee joint sensitivity to a pressure stimulus was unaffected in male and female MMT rats, and dynamic weight loading was also unaffected in male and female rats undergoing MMT surgery. Reference analgesic compounds were evaluated in the MIA model examining the effects on hindlimb mechanical allodynia and weight bearing deficits both at baseline (week 1) and at the end (week 6) after osteoarthritis induction. At week 1, single doses of morphine (3 mg/kg) significantly reduced mechanical allodynia and weight bearing deficits in male and female rats, whereas single doses of ketoprofen (6 mg/kg) or duloxetine (60 mg/kg) were less effective. In contrast, repeated administration of ketoprofen or duloxetine (4 days, twice daily) significantly reduced mechanical allodynia and weight-bearing deficits at week 1. At week 6, morphine, ketoprofen, and duloxetine were ineffective in reducing deficits weight bearing.

Conclusions:The results of these studies demonstrate that a variety of pain behaviors associated with osteoarthritis of the knee joint can be measured using the MIA mouse model, whereas pain behaviors in the MMT model were less robust or unobservable. Evaluating new drugs after single and repeated administration in the MIA model using multiple pain outcomes may be a viable strategy to accelerate the development of non-opioid and non-addictive therapies to treat osteoarthritis pain. The usefulness of valuing new assets at week 1 versus week 6 remains to be explored.

Key words:Chronic pain, monoiodoacetate model of osteoarthritis, preclinical pharmacology

Disclosure:Nothing to disclose.

Wang Chang*

Harvard Medical School, Massachusetts General Hospital, Charlestown, Massachusetts, EUA

Background:The acetylation/deacetylation of histone lysine residues represents an important epigenetic modification that affects gene expression without modifying the DNA sequence. Histone deacetylases (HDACs) are a class of amide hydrolases that catalyze a variety of substrates, including histones and other proteins. Eleven Zn2 + -dependent HDACs have been found in mammals, including class I (HDAC1, HDAC2, HDAC3, HDAC8), class IIa (HDAC4, HDAC5, HDAC7, HDAC9), class IIb (HDAC6, HDAC10) and class IV (HDAC11 ). ), each of these isoforms has distinct roles in epigenetic regulation. Among them, HDAC11 is the most recently identified member of the class IV HDAC with increasing evidence pointing to an association with many diseases. Some selective HDAC11 inhibitors have been reported in recent years, but none have shown penetration into the brain, nor have they been studied in animal models of neurological disorders. Here we describe the development and characterization of a selective HDAC11 inhibitor, PB94, identified by structural optimization of our lead compounds and evaluated for therapeutic efficacy in neuropathic pain.

Methods:HDAC Enzyme Inhibition Tests 1-11. HDAC inhibition assay of target compounds was performed at Nanosyn (Santa Clara CA, USA). Test compounds were diluted in 100% DMSO using 3-fold dilution steps. TSA was tested identically.

Chronic constrictive lesion (CCI). Mice (n = 8 in each group) were anesthetized in an anesthetic induction chamber. The lower left extremity was dissected with an alcohol swab. A 0.5 to 1 cm incision was made in the lower left extremity with a scalpel. The left side of the sciatic nerve was exposed mid-thigh. Four ligatures with 6.0 mm chronic intestinal sutures were placed loosely around the exposed sciatic nerve with a spacing of 1.0-1.5 mm between each ligature. The skin incision was closed with two 6-0 vicryl stitches.

Mechanical extraction threshold. Mice were habituated by placing them individually on a platform with a transparent chamber for 30 minutes a day for 3 consecutive days. Mechanical paw withdrawal thresholds (PWT) were performed using manually calibrated von Frey filaments. A positive response was recorded when the mice withdrew their paw or shook their paw during stimulation. A negative response was followed by a test with the next largest filament. All CCI mice were tested before surgery (baseline) and 3, 5, 7, 10 and 14 days after surgery.

Latency in hind paw withdrawal. Mice were placed on a pre-warmed glass platform (28-29°C) and clear acrylic booths to acclimatize to the test room for 30 minutes daily for 3 consecutive days prior to testing. Paw withdrawal latency was defined as the time (seconds) from the onset of heat exposure to hind paw withdrawal. A shutdown time of 20 seconds was set to prevent tissue damage.

Results:A series of analogues of lead compounds were synthesized to study the structure-activity relationship (SAR). Among them, PB94 had significant HDAC11 potency and the highest HDAC11 selectivity (IC50 = 108 nM and more than 39 times over other HDAC isoforms.

ADME assessments were then performed to assess the drug-like profiles of PB94. Our data showed that PB94 has good metabolic stability in human liver microsomes and mouse plasma with half-lives (t1/2) of 54.6 min and 133.8 min, respectively. Furthermore, no significant inhibitory effect on cytochrome P450 (CYP) enzymes 1A2, 2C19 and 2D6 was observed at 10 µM PB94. PB94 has a very good brain to plasma ratio of 2.3 at 30 minutes and 2.2 at 4 hours post injection by IP administration of PB94 at 1 mg/kg in C57BL/6 mice. Furthermore, we tested its off-target binding on a panel of 46 targets (PDSP) and did not observe any significant off-target binding at 10 µM.

To investigate the potential roles of HDAC11 in a disease state, we chose a mouse model of neuropathic pain, chronic sciatic nerve constriction (CCI) injury. 14 days after surgery, HDAC11 protein was elevated in the cortex compared to sham mice, suggesting that HDAC11 is critically involved in pain and that targeting HDAC11 may have therapeutic effects. To test them, we administered PB94 to mice subjected to CCI to assess the development of nociceptive behavior. PB94 (10 mg/kg) significantly reduced mechanical and thermal pain-like behaviors during the 14-day trial period. Importantly, no significant side effects were observed during PB94 treatment. The body weight of mice remained similar between animals treated with saline or PB94.

Conclusions:The promising pharmacological properties of PB94 support its therapeutic potential in neurological diseases. As HDACs were associated with neurological pain, we further determined whether PB94 treatment could improve neurological pain using the CCI mouse model. Unilateral surgery for chronic sciatic nerve constriction injury is associated with spontaneous postoperative pain, mechanical allodynia, and thermal hyperalgesia. In our study, a battery of tests was used to assess the analgesic effect of PB94 on pain-like behaviors, yielding results that support its efficacy at 10 mg/kg. HDAC11 has been reported to be disseminated in rodent brains. Even more interesting, we found an upregulation of HDAC11 in the somatosensory cortex of CCI mice. Therefore, it is reasonable to postulate that increased expression of HDAC11 in somatosensory cortex may be involved in persistent nociception after CCI surgery and that inhibition of HDAC11 by PB94 in CCI may attenuate neuropathic pain.

Key words:Epigenetics, pain therapy, CNS drugs

Disclosure:Nothing to disclose.

Kimberlei Richardson*, Alexa Ryan, Nia Sweatt, Victor Apprey, Robert Taylor, Kalpna Gupta

Howard University, Washington, District of Columbia, United States

Background:Orexins are neuropeptides synthesized in the perifornic area (PFA), lateral hypothalamus (LH) and dorsomedial hypothalamus (DMH) that mediate arousal, sleep, energy balance, eating, and drug reward. Data suggest that the neuropeptide orexin-A has an analgesic effect on inflammatory pain by binding to the orexin-1 receptor. It may also affect the mechanisms underlying the maintenance of hyperalgesia associated with neuropathic pain. Data from our previous study suggest that subpopulations of orexin neurons are preferentially recruited for hyperalgesia during behavioral assessments. Our aim was to determine whether there are differences in pain scores following orexin-1 receptor antagonism (SB-334867) and whether this pain is potentiated in sickle cell mice expressing exclusively (99%) human sickle cell hemoglobin (HbSS-BERK) and age . / Sex-matched controls (HbAA-BERK).

Methods:HbSS-BERK and HbAA-BERK transgenic female mice (n=6/group, 20-30 g) were habituated to each test protocol for thermal/heat and mechanical hyperalgesia. Thermal/heat hyperalgesia was controlled by plantar testing (Hargreave machine) for thermal stimulation. Latency was measured as the time (in seconds) for the mice to withdraw their hind legs from the heat stimulus. Mechanical hyperalgesia was controlled with the von Frey filament test. Paw withdrawal frequency was measured by the number of times the mice raised their hind paws after tactile stimulation of the filaments. Performance data were recorded before SB-334867 (20 mg/kg, IP), 1 hour and 24 hours after injection.

Results:Significant time-dependent differences in heat latency were observed after SB-334867. Mean heat latency for HbAA mice did not differ significantly between different time points (p-value = 0.103). Mean heat latency for HbSS-BERK mice was significantly different between time points (p-value = 0.004), and post-hoc testing showed significant reductions in heat latency in HbSS versus HbAA-BERK mice prior to SB-334867 (p<0.05) and 1 hour after SB-334867 (p<0.005). There was a significant reduction in heat latency in HbSS-BERK mice only when we compared observations before SB with 1 h after SB-334867 (p<0.05). Statistical analyzes are ongoing to determine time-dependent differences for mechanical hyperalgesia.

Conclusions:These findings suggest differential orexin receptor responsiveness in HbSS-BERK versus HbAA-BERK mice. These data may provide a mechanism for increased hyperalgesia in HbSS-BERK mice, contributing to the neuropathic pain seen in sickle cell anemia.

Key words:Hyperalgesia, orexin receptor antagonist, sickle cell anemia

Disclosure:Nothing to disclose.

Gary Sachs*, Jenicka Engler, D. Thorpe, Miriam Evans, D. Fagundo, S. Starling, S. Nicholas, H. Zandi, M. Moy, A. Vittoria

Signant Health, Lincoln, Massachusetts, EUA

Background:Sample collection is the key to successful clinical trials. Social media promotion is now a common means of initial recruitment, with notable success in increasing study applications prior to screening, but slow enrollment remains a chronic problem. As efforts to address slow enrollment by increasing compensation for time and travel risks increase enrollment of unsuitable participants and so-called "professional subjects," the goal of enrolling an adequate study sample through recruitment efforts to attracting volunteers "seeking clinical trials" may be harmed ." rather than representative participants of patients "seeking treatment".

In particular, recruitment into major depressive disorder (MDD) clinical trials is considered to be particularly challenging, as depressive symptoms may pose a barrier to participation in screening visits.

To address this complex issue, we ask a simple question: Does the “baseline promise” for post-trial treatment effects demonstrate enrollment numbers and quality for MDD studies?

Most current quality control methods aim to disqualify enrollment in clinical trials inappropriate for MDD after the screening assessment. This pilot study examines the impact of pre-screening recruitment messages that best target the interests of "treatment-seeking" individuals, which clearly represents an offer of referral to post-trial clinical care as a benefit of study participation.

This pilot experiment examines differences at various points in the recruitment and enrollment process (recruitment funnel) between participants who received promised referrals (experimental group) and a control group who received the usual study recruitment messages.

Methods:Starting in mid-May 2022, potential survey participants were recruited and randomized using Facebook's A/B testing algorithm. The algorithm randomly assigned users to either a control group, which displayed our usual Facebook ad content (information about MDD and clinical trials), or the experimental group, which displayed promotional text about MDD clinical trials and a promise that all respondents would provide treatment provider recommendations, and information about clinical trials would be obtained. Resources regardless of test eligibility. Both groups received telephone assessment interviews with Adams Clinic staff, followed by an in-person pre-assessment consultation. For those in the experimental group, recruiters and physicians repeated the promise of resources and referrals through IRB-approved roadmaps. Those in the experimental group who completed the telephone screening but did not qualify for the study or who declined were given information for the local NAMI. Those who attended the face-to-face screening appointment and were ineligible or denied received a treatment recommendation letter containing the results of the screening assessment and treatment recommendations, NAMI information, and at least 2 referrals to local physicians within the network, to be designated how new references are acceptablely listed in psychology today. .com The two groups were compared for phone screen fill rates, completion of the prescreening process, and study eligibility using chi-square.

Results:A total of 1,358 potential research participants clicked on Adams Clinical Facebook ads and submitted their contact information online as part of this A/B testing experiment (n=751 in the experimental group and n=607 in the control group). Participants in the experimental group were significantly more likely to complete a telephone assessment (22%) than those in the control group (16%), X2 (1, N = 1358) = 6.46, p = 0.011. Participants in the experimental group were significantly more likely to schedule a screening visit (83%) than the control group (68%), X2(1, N=265)=8.03, p=0.005. The effect on attendance at the screening visit reached borderline significance, with participants in the experimental group being more likely to attend the screening visit (49%) than those in the control group (35%), X2 (1, N=190 ) = 3.19, p = 0.074. The effect on study eligibility also reached borderline significance, as participants in the experimental group were more likely to be eligible (48%) than those in the control group (27%), X2 (1, N = 85) = 2, 78, p = 0.096.

At this point, planned pre-assessments and assessment visits for both groups are pending. Data on all participants will be available prior to the meeting so that full data on pre-screening participation and consent to participate in the study can be presented on this poster.

Conclusions:To the best of our knowledge, this pilot study represents the first empirical data on efforts to improve recruitment, providing a compelling value proposition for patients seeking treatment. We found that promising to refer potential MDD study participants and providing resources had a positive impact at all points examined in the recruiting funnel.

Our results suggest that articulating and executing this value proposition has the potential to accelerate trial recruitment by significantly increasing the likelihood that potential participants will complete both a telephone screening and an in-person pre-screening visit. More work is needed to determine whether increased willingness to participate in the clinical research selection process is associated with better trial participation rates, better sample quality, and greater potential for signal detection.

Key words:Clinical trial methodology, recruitment, use of social networks, mood disorders

Disclosure:Signatory health: employees (own)

Mercedes Szpunar*, Marlene Freeman, Lauren Kobylski, Ella Rossa, Peter Gaccione, David Chitayat, Sonia Hernandez-Diaz, Adele Viguera, Lee Cohen

Hospital Geral de Massachusetts, Harvard Medical School, Boston, Massachusetts, EUA

Background:The prevalence of Attention Deficit Hyperactivity Disorder (ADHD) in adult women is 3-4%. ADHD is highly comorbid with other psychiatric disorders such as mood, anxiety, and substance use disorders. In women of childbearing potential, treatment for ADHD with stimulant drugs may be considered during pregnancy or lactation, although historically there has been a lack of data to support these decisions. The purpose of this study was to determine the risk of serious birth defects in infants after exposure to stimulants in the first trimester.

Methods:The Massachusetts General Hospital National Pregnancy Registry for Psychiatric Drugs was created in 2008 to advance knowledge about the reproductive safety of psychiatric drugs through rigorous prospective data collection. The registry routinely reviews its participants' information, including demographic information, medical and psychiatric history, use of prescription medications, and other information relevant to the fetal outcome. Participants provide oral informed consent and are interviewed twice during pregnancy and again approximately 3 months after delivery. The primary finding of interest is the presence of a major malformation identified within 6 months of birth. Blackened cases of large malformations are reviewed by a dysmorphologist, ignoring drug exposure. Women who took stimulants during the first trimester of pregnancy (n=233) were compared to controls (n=1755 women) who took other psychiatric medications for the treatment of mental disorders during pregnancy. The study is registered with ClinicalTrials.gov (NCT01246765).

Results:N=1988 women eligible for this analysis, including n=173 women with mixed amphetamine exposure, n=40 with lisdexamfetamine exposure, n=45 with methylphenidate exposure, and n=3 with dexmethylphenidate exposure; the comparison group comprised n = 1755 women. A total of 235 babies were exposed to one or two stimulants due to twin pregnancies. The odds ratio for a major malformation in infants after exposure to a stimulant during the first trimester was 0.57 (95% CI 0.17 to 1.85) compared with controls. The odds ratio for a major malformation after exposure to mixed amphetamines or lisdexamfetamine was 0.70 (95% CI 0.70 to 2.28). No serious malformations have been observed in infants exposed to lisdexamfetamine, methylphenidate or dexmethylphenidate. The prevalence of severe malformations after first-trimester exposure to amphetamine mixtures was 1.2%.

Conclusions:Although preliminary, this analysis of an ongoing pregnancy registry provides evidence that these prescription stimulants do not appear to have significant teratogenic effects.

Key words:ADHD, stimulants, pregnancy

Disclosure:Interpros: official (spouse)

Mark Weiser*, Ariel Asper, Adam Noy, Michael Davidson, Itzhak Levav, John M. Davis

Sheba Medical Center, Ramat Gan, Israel

Background:Data suggest that a psychiatric diagnosis has a negative association with lifetime earnings. We examined the impact of a psychiatric diagnosis among 25- to 34-year-olds on income among 63- to 72-year-olds.

Methods:Baseline scores were obtained from a population-based epidemiological study with a random sample of 5,000 individuals aged between 25 and 34 years, conducted in Israel in the 1980s; subjects are now between 63 and 72 years old. Data on average annual earnings between 1983 and 2018 were obtained from the Israel Social Insurance Agency. For each participant, the median of their mean annual income was calculated; For each diagnostic group, the average of the participants' medians was calculated. The difference (in standard deviations) between mean annual income between healthy participants and each diagnostic group was calculated.

Results:The healthy participant had the highest mean annual income. Mean income varies by diagnosis: anxiety: -0.2 SD, depression: -0.43 SD, unstable personality disorder -0.49 SD, bipolar disorder -0.52 SD, schizotypal personality disorder -0 .58 SD, antisocial personality disorder -0.84 SD, schizophrenia - .96 SD.

Conclusions:Young adults diagnosed with psychiatric disorders earn significantly less money over a lifetime than young adults without psychiatric disorders. These longitudinal data suggest that having a psychiatric diagnosis increases the risk of having a low income, but cannot rule out that having a low income also increases the risk of having a psychiatric disorder.

Key words:Psychiatric disorders, income, based on population

Disclosure:Jansen: Advisory Board (self), Teva: Advisor (self), Dexcel: Advisor (self), Lundeck: Advisory (self), Minerva: Research Agreement (self), MSD : Consultant (at own expense), Pfizer: charges (at own expense). ), Orion: Counselor (Auto), Clearmind: Counselor (Auto)

Hanna Molla*, Tang Li, Sonja Lyubomirsky, Harriet de Wit

University of Chicago, Chicago, Illinois, USA

Background:MDMA is classified as an "empathogenic" drug because it increases feelings of empathy and closeness to others. These effects are thought to be mediated in part by increased oxytocin release through increased serotonergic transmission. Despite its prosocial effects, few human studies have examined MDMA in the context of interpersonal interactions. The objectives of this study were to determine the effects of MDMA on feelings of closeness and connectedness during semi-structured dyadic conversations and to investigate the relationships between feelings of closeness and oxytocin levels. To investigate pharmacological specificity, a separate group of subjects were tested with the prototype stimulant methamphetamine.

Methods:Two studies were conducted on separate groups of healthy volunteers. In double-blind, placebo-controlled, "intraindividual" designs, subjects aged 18 to 35 years received a single dose of MDMA (100 mg) or placebo (Study 1; n=18), or a single dose of methamphetamine (Study 1; n=18). 20 mg) or placebo (Study 2; n = 19) during two lab sessions 72 hours apart. During the peak of the drug's effects, they conducted a 45-minute semi-structured interview with a new same-sex partner. Subjective mood, physiological and oxytocin levels were recorded at regular intervals, and subjects rated feelings of closeness and connection with their partners at the end of each session and one week later.

Results:Both MDMA and methamphetamine increased ratings of feeling connected to a partner and increased ratings of pleasure and conversation relevance compared to placebo (MDMA Study 1; p = 0.009 and Methamphetamine Study 2 p = 0.01). Both MDMA and methamphetamine increased subjective ratings of "sociable", "affectionate" and "friendly". Only MDMA increased trust, gratitude, and appreciation ratings, and only methamphetamine increased MDMA comprehension ratings (p = 0.001) and, to a lesser extent, methamphetamine (p = 0.02) increased salivary oxytocin levels . Notably, oxytocin levels correlated positively with feelings of closeness after MDMA but not after methamphetamine (Study 1; r = 0.52, p = 0.03).

Conclusions:Both MDMA and methamphetamine increased feelings of closeness and connection with strangers during controlled interpersonal interactions, and both drugs increased subjective sociability ratings. However, these feelings were only associated with oxytocin after MDMA, suggesting that the mechanisms mediating prosocial effects may differ between drugs. This study provides a model for future studies evaluating the effects of drugs on interpersonal interactions.

Key words:MDMA, social interaction, oxytocin, proximity, stimulant

Disclosure:Nothing to disclose.

Naomi Fineberg*, Pellegrini Luca, Aaron Clarke, Jemma Reid, Keith Laws

University of Hertfordshire, Welwyn Garden City, UK

Background:Mass vaccination against COVID-19 heralded a return to normalcy after the recent pandemic. The success of this initiative must be placed in the context of a sizable minority who are opposed to vaccination. Understanding the factors that influence vaccine attitudes and intentions is an important element in the arsenal against this and any future pandemic (1). Objective cognitive tasks have certain advantages over clinical measurements in that they may be less prone to rater-related errors and may provide insight into underlying neuropsychological mechanisms. Few studies have examined cognitive function in relation to vaccine hesitancy. One such study identified a broadly defined relationship with executive functioning using a Stroop task and the Montreal Image Stress Task (2). Another (3) identified a relationship with self-control in a Stroop task. A third (4) found evidence of association with flexible adaptation to new concepts. In a quarter (5), parental psychological flexibility and a positive coping style were associated with reduced COVID-19 vaccine skepticism in a pediatric sample. To our knowledge, this is the first study to examine the relationship between cognitive inflexibility and COVID-19 hesitation in a large sample of adults using a specific digital neurocognitive task (Wisconsin Card Sort Task; WCST).

Methods:This study is part of a larger research program examining post-pandemic adaptation. The study was approved by the Ethics Committee for Health and Human Sciences with Delegated Authority (ECDA) of the University of Hertfordshire (LMS/PGR/UH/04554) and a protocol was previously registered in the Open Science Framework (OSF). 🇧🇷https://doi.org/10.17605/OSF.IO/XD5WZ🇧🇷 We interviewed adults from the UK adult population (>18 years) between June 2021 and July 2022 (using Gorilla software), during a period when lockdown restrictions were being relaxed. Different groups were chosen to recruit a sample that included traditionally neglected groups, such as people with mental disorders. Sociodemographic information (age, gender, education and ethnicity) was collected. Cognitive inflexibility was measured using a digital version of the WCST. For this analysis, we focused on WCST-Persevering-Errors as the most specific item to capture attention switching issues. Resistance to vaccination was measured using the Oxford Covid Vaccine Hesitancy Scale (OCVHS). We performed correlation and regression analyzes to identify possible associations between cognitive inflexibility and vaccine hesitancy.

Results:A sample of 207 people completed the survey and the WCST. The average age of the sample was 37.3 years, 68% were female, 61% identified as white, 28% Asian, 5.8% South American and 6.3% African. The overall OCVHS mean was 12.8 (SD: 6.9), which corresponds to the mean of a larger population sample (mean 13.6 (SD: 7.3)) (6). A statistically significant correlation was found between persistent WCST errors and total OCVHS (Pearson's r, p = 0.003). We performed a multivariate regression analysis in which we included OCVHS as an outcome, persistent failures as a predictor, and sociodemographic factors considered to influence vaccine hesitancy (age, gender, education, ethnicity) as covariates. Even after controlling for these covariates, persistence errors significantly predicted greater vaccine aversion (p = 0.01).

Conclusions:Cognitive inflexibility, measured with a computer-based objective neurocognitive task in a large sample of the adult population, was a significant predictor of vaccine aversion independent of age, gender, educational level, and ethnicity. Cognitive inflexibility is often a persistent trait (7) and may provide a “red flag” of vaccine reluctance to identify individuals most at risk of refusing vaccines in current and future pandemics. Public health education strategies need to consider the impact of an inflexible thinking style on the decision-making of those most at risk of vaccinating reluctance and adjust interventions accordingly.

References:

1. Wang Y, Zhang X. Frontiers in Psychology 2021;12

2. Acar-Burkay S, Cristian DC. Soc Sci Med 2022;301:114911.https://doi.org/10.1016/j.socscimed.2022.114911

3. Cao and Li 2022, Pers Indiv Diff 188:11147

4. Mazzuca C, et al. 2021.https://doi.org/10.31234/osf.io/4ndb8.

5. Wang Y, Zhang X. Frontiers in Psychology 2021;12.

6. D. Freeman, BS Loe, A. Chadwick, C. Vaccari, F. Waite, L. Rosebrock et al. Psychologische Medizin 2020: 1–15.https://doi.org/10.1017/S0033291720005188

7. Chamberlain SR, Fineberg NA, Menzies LA, Blackwell AD, Bullmore ET, Robbins TW, et al. Am J Psychiatry 2007;164:335–8.https://doi.org/10.1176/appi.ajp.164.2.335.

Key words:Cognitive inflexibility, vaccine hesitancy, public health, COVID-19

Disclosure:Nothing to disclose.

Lee Cohen*, Marlene Freeman, Lauren Kobylski, Ella Rossa, Charlotte Clifford, Sonia Hernández-Díaz, David Chitayat, Adele Viguera

Mass General Hospital, Harvard Medical School, Boston, Massachusetts, EUA

Background:Second-generation antipsychotics (SGA), or atypical antipsychotics, are commonly used by women of childbearing age to treat a variety of psychiatric disorders. The National Pregnancy Registry for Psychiatric Medications (NPRPM) is a systematic prospective pharmacovigilance program used to collect data on the reproductive safety of second-generation antipsychotics and other classes of psychiatric drugs to inform the care of women of reproductive age with mental disorders. 🇧🇷

Methods:Data are collected prospectively from women aged 18 to 45 with a history of psychiatric disorders. Two telephone interviews will be conducted during pregnancy and a third interview will be conducted 3 months after delivery. Enrollment and longitudinal follow-up of participants is ongoing. In this analysis, the exposed group consists of women who received SGA during the first trimester of pregnancy. The comparison group consists of women who did not use this class of drugs during pregnancy but were exposed to other psychotropic drugs prenatally. Information about the presence of major malformations is extracted from medical records, and identified cases of possible major malformations are evaluated by a dysmorphic specialist blinded to drug exposure and psychiatric diagnoses.

Results:As of July 25, 2022, 2676 women were enrolled in the NPRPM, 1031 in the exposure group and 1551 in the comparison group. Medical records were obtained from 78% of participants. A total of 1997 participants (787 exposed to SGA in the first trimester, 1210 not exposed to SGA during pregnancy) were eligible for analysis after completing the postpartum interview. Of 810 children in the exposure group, 22 confirmed severe malformations were identified. In the control group, comprising 1,234 infants, 19 malformations were identified. A consistent pattern of malformations was not observed in either group. The absolute risk of serious malformations was 2.72% in the exposure group and 1.54% in the comparison group. The odds ratio was OR=1.79 (95% CI: 0.96–3.32).

Conclusions:The NPRPM provides a systematic way to collect prospective reproductive safety information that informs the care of women who may be using second-generation antipsychotics to maintain psychiatric well-being. Current data suggest that ASGs, as a class, are unlikely to have a significant teratogenic effect. Future analyzes will aim to better estimate the risk of severe malformations with even larger sample sizes and generalizable cohort characteristics. We continue to evaluate the reproductive safety of individual drugs in this class. In addition, we are investigating other classes of drugs such as B. new antidepressants and drugs used to treat ADHD and insomnia.

Key words:Pregnancy, Bipolar Disorder, Atypical Antipsychotics, Depression, Reproductive Psychiatry

Disclosure:Alkermes Inc., Johnson und Johnson/Janssen Pharmaceuticals Inc., Otsuka America Pharmaceutical, Inc., Sage Therapeutics, Sunovion Pharmaceuticals Inc., Supernus Pharmaceuticals, Teva Pharmaceutical Industries Ltd., Forest/Actavis/Allergan:, AstraZeneca Pharmaceuticals, AuroMedics Pharma LLC , Aurobindo Pharma, Ortho-McNeil-Janssen Pharmaceuticals Inc., Pfizer Inc., MGH CTNI, Brain and Behavior Research Foundation, Instituto Nacional sobre el Envejecimiento, Institutos Nacionais de Saúde, SAGE Therapeutics: Otro apoyo financiero o material (auto), JDS Therapeutics LLC: Repreendedor (Propio)

Kristina Legget*, Marc-Andre Cornier, Lauren Sarabia, Eve Delao, Susan Mikulich, Christina Erpelding, Tessa Mitchell, Jason Tregellas

University of Colorado School of Medicine, Aurora, Colorado, USA

Background:Obesity is rapidly increasing, raising numerous health and quality of life concerns. Responsiveness to food cues is a key factor underlying eating behaviors that may contribute to obesity. However, a crucial factor in understanding these relationships is how the response to the food stimulus can differ between men and women, including gender differences in factors that may be related to the response to the food stimulus, such as: B. weight, eating habits and mood . Therefore, the aim of the present study was to examine gender differences in both the attractiveness and "desire to eat" of high-calorie and low-calorie foods, including the influence of gender on the relationships between ratings of eating tips and BMI. , intake behavior and measures of mood.

Methods:334 adults (164 men, 169 women) completed this study by responding to an online survey in a neutral state of hunger. Survey measurements included weight and height (from which BMI was calculated); the Three Factor Eating Questionnaire (TFEQ), which assesses eating behaviors based on characteristics related to moderation, disinhibition and hunger; the Eating Attitudes Test 26 (EAT-26), which assesses behaviors related to eating disorders; the Center for Epidemiological Studies Depression Scale (CESD-R), which assesses symptoms associated with depression in the last week; the Perceived Stress Scale (PSS), which assesses feelings of stress in the past week; and the Visual Analog Scale (VAS) measures current hunger (“how hungry are you?” from “not at all hungry” to “extremely hungry”) and satiety (“how full are you right now?” from “not hungry”). full” to “extremely full”), on a scale from 0 to 100. After completing these questionnaires, participants started the Food Picture Task, for which they observed 96 images of different foods (48 high-calorie and 48 low-calorie). calorie content) and asked , to rate how appealing each image was and how much of it they wanted to eat. Food using a visual analogue scale (0-100). Independent-sample t-tests were used to determine group differences (men vs. women) in questionnaire scores (TFEQ: Restraint, Disinhibition, and Hunger Scores; EAT-26 Eating Disorder Behavior Total Score; CESD-R Depression; PSS Perceptual Stress Score; VAS scores for hunger and satiety) and attractiveness and "craving to eat" ratings on the food image task, separately for high-calorie (HC) and low-calorie (HC) foods , calories (LC). Regression models examined how questionnaire results related to HC and LC ratings of attractiveness and desire to eat on the food imagery task. Gender-based interactions were included in the analyses; Models with insignificant interactions based on gender were retested without the interaction component.

Results:Two women were excluded from further analysis as outliers for BMI (BMI >60kg/m2), with 27 (12 men, 15 women) being excluded because they were outliers in time to survey completion (>75min). Thus, 306 participants were included in the final sample (151 men, 155 women). Compared to men, women in the sample reported significantly greater food restriction (p = 0.004), disinhibition (p < 0.001) and trait-based hunger (p = 0.044) as measured by the TFEQ. Significantly higher scores on the EAT-26 were also observed in females compared to males (p<0.001), as well as significantly higher levels of perceived stress (p<0.001) and depression (p<0.001). We did not observe gender differences in the “desire to eat” of HC or LC foods or in the attractiveness of HC foods (p > 0.05 for all), but women reported greater attractiveness of LC foods compared to men (p = 0.002) . A significant interaction with gender was observed in the relationship between perceived stress and HC food attractiveness (p = 0.006), such that greater stress was associated with greater HC attractiveness in men, but with lower HC attractiveness in women. For LC food attractiveness, we observed a significant gender-based interaction with disinhibition (p = 0.024), such that greater disinhibition was associated with lower LC attractiveness in women but greater LC attractiveness in men. In both groups, increased satiety was associated with decreased LC food cravings, but there was a gender interaction, such that stronger associations were seen in women compared to men (p = 0.049). In all sexes, increased BMI was associated with greater attractiveness to HC foods (p = 0.042), with increased depression scores being associated with greater cravings for HC foods (p = 0.008). No association was observed between BMI and LC foods, but increased depression scores were associated with increased desire to eat LC foods (p = 0.008), and increased perceived stress was associated with increased LC food stimulation ( p = 0.009).

Conclusions:We observed greater food restriction, disinhibition, and trait-based hunger in women compared to men, in addition to greater attractiveness of LC foods. Higher scores for behaviors related to eating disorders, depression and perceived stress were also observed in women compared to men. Interestingly, we observed a gender-specific interaction between perceived stress and HC attractiveness, with greater stress being associated with decreased HC attractiveness in females but increased HC attractiveness in males. This may indicate differential effects of stress on the eating behavior of women compared to men, which may indicate that stress is an important factor to consider in individualized approaches to weight management. Across all groups, BMI was associated with greater HC attractiveness, stress with greater LC attractiveness, and depression with HC and LC cravings, further underscoring the importance of considering the role of status, mood in eating behaviors and maintenance approaches. of weight.

Key words:Obesity, gender-specific effects, eating stimuli, eating behavior, mood

Disclosure:Nothing to disclose.

Kongpyung Kim, Shin-ichi Kano, Minae Niwa*

University of Alabama at Birmingham, Birmingham, Alabama, United States

Background:Postpartum social behavior is not only important for the health of the mother, but also for the development of the child. Unfortunately, postpartum social behavior is sensitive to the stress that can occur at different times in the mother's life. Adolescent stress may be associated with changes in postpartum behavior, including social behavior. However, the neural circuitry mechanisms by which adolescent stress leads to postpartum changes in social behavior are unclear. We recently found that mice exposed to late adolescent social isolation (SILA), which by itself does not cause endocrine or behavioral changes, exhibit persistent behavioral deficits only when accompanied by pregnancy and delivery. Behavioral deficits in SILA-exposed mothers (stressed mothers) were caused by abnormally sustained increases in corticosterone levels during the postpartum period. Most importantly, we have shown that short-term postpartum treatment with a glucocorticoid receptor (GR) antagonist is sufficient to improve behavioral deficits seen in stressed mothers (Niwa et al. BioRxiv 2021). Using this mouse model, we also found that SILA associated with pregnancy and childbirth leads to hypofunction of the anterior insula-prelimbic cortex glutamatergic signaling pathway (AI-PrL), which in turn alters activity patterns in the PrL , leading to behavioral changes on social media . Novelty recognition (Kim and Niwa, ACNP 2021). Based on these results, the present study investigated whether increased corticosterone signaling in the AI-PrL pathway leads to changes in social behavior in postpartum stressed mothers.

Methods:AAVretro-CaMKIIa-EGFP and a mixture of CRE-DOG viruses (AAV1-EF1a-N-Cretrcint G and AAV-EF1a-C-Creint G) were bilaterally injected into PrL and AI from mice carrying the GR gene (GRfl /fl mice ), eight-week-old B6J or Ai14 mice. AAV1-Flex-tdTomato was also injected into AI for a validation study using B6J mice. For Cre-GFP-dependent recombinase (CRE-DOG) validation studies, mice were perfused one, two, or three weeks after virus injection. EGFP +, tdTomato+EGFP +, EGFP + GR +, mCherry + or mCherry+GR + cells were counted. For the behavioral cohort, animals (5 to 8 weeks old) were challenged with SILA after surgery. Each mouse was mated with a healthy male C57BL/6J and gave birth to pups. Three-chamber social interaction tests (SIT) were performed one week after birth. Two hours after the last behavioral test, mice were perfused for c-Fos staining.

Results:Pathway-specific GR knockout (GR-KO) mice were successfully generated by combining the GFP-dependent Cre recombinase system and AAV-mediated retrograde scanning in GRfl/fl mice. The CRE-DOG method, which used GFP binding proteins to molecularly assemble Cre recombinase onto a GFP scaffold, allowed us to express Cre recombinase in a GFP-dependent manner. We validated that Cre recombinase was successfully expressed in the AI-PrL pathway when AAV retro-CaMKIIα-EGFP and a CRE-DOG virus mix (AAV-EF1a-N-Cretrcint G and AAV-EF1a-C -Creint) were injected G ) in PrL or AI. Over time after the injections, a gradual increase in the level of EGFP expression in the AI ​​was observed, accompanied by a gradual decrease in the level of GR expression in the LA neurons that express EGFP. Such expression changes were not observed when AAV-retro-CaMKIIα-mCherry was injected instead of AAV2-retro-CaMKIIα-EGFP as a control virus. GR deletion in the AI-PrL pathway increased behavioral changes in the social novelty test but not in the SIT sociability test in stressed prey. AI-PrL-specific GR-KO also normalized reduced c-Fos immunoreactivity after social novelty studies in stressed mothers. These results suggested that activation of GR signaling in the AI-PrL pathway, but not in PrL itself, may play a causal role in PrL dysfunction and subsequent behavioral changes in recognizing social innovation in the postnatal learning period.

Conclusions:We successfully generated path-specific GR-KO mice using the CRE-DOC method. Using these GR-KO mice, we elucidate the causal role of GR-mediated AI-PrL signaling in postpartum behavioral changes during social novelty recognition. Further investigation of how GR signaling specifically regulates AI-PrL function and social cue recognition would facilitate our mechanistic understanding of the pathological course of adolescent stress leading to abnormal social behaviors in the postnatal period.

Key words:Adolescent stress, social behavior, glucocorticoid receptor, anterior insula, prelimbic cortex

Disclosure:Nothing to disclose.

Derya Sargin*, Matthew Dawson, Dylan J. Terstege, Naila Jamani, Dmitrii Pavlov, Mio Tsutsui, Jonathan R. Epp, Gina M. Leininger

Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Universidad de Calgary, Calgary, Kanada

Background:Intraspecific social interactions are an essential part of the survival and maintenance of society for all mammalian species. However, our understanding of the neural systems and mechanisms involved in establishing social connections and the consequences of the adverse effects of social isolation are limited. Since their initial discovery as sleep/wake and appetite regulators in the brain, hypocretin/orexin neurons have also been shown to play essential roles in modulating energy homeostasis, motivation and emotional behavior. These neurons are found exclusively in the hypothalamus, which regulate complex and goal-directed behaviors. The hypothalamus has previously been shown to play an important role in modulating social behavior by encoding internal states. However, information on the role of hypocretin neurons in social behavior and deficits is limited.

Methods:We infused AAV encoding GCaMP6s into the LH of female and male Hcrt-cre mice and performed fiber photometry to record the activity of the hypocretin neuron population during social interaction. We then inhibited the activity of hypocretin neurons using optogenetics and determined the need for these neurons for social behavior in female and male mice. Using a model of chronic social isolation in mice, we also determined how hypocretin neuron activity is affected in mice with social deficits.

Results:We identified hypocretin/orexin neurons that show a strong increase in activity in response to social interaction in female and male mice. We show that the activity of the hypocretin neuron population is differentially encoded during interactions between familiar and non-familial conspecifics. Furthermore, optogenetic inhibition of hypocretin neuron activity during social behavior leads to a reduction in the time that mice engage in social interaction in a sex-specific manner. We also show that isolated mice exhibit deficits in social behavior and disruption in hcrt neuron activity.

Conclusions:Collectively, these data represent the hypocretin/orexin system as part of a larger network that plays an integral role in modulating social behavior. Here we will also discuss the implications of these findings in an animal model of chronic social isolation that develops long-term social impairments.

Key words:Orexin/hypocretin, social isolation, social deficits, fiber photometry, optogenetics

Disclosure:Nothing to disclose.

Julio Licinio*, Eunice Chin, Qin Ma, Hongyu Ruan, Camile Chin, Aditya Somasundaram, Ma-Li Wong

State University of New York, Syracuse, New York, USA

Background:We report that the PHF21B gene is located in the genomic region of the human chromosome 22q13.31. 22q13.3 deletion syndrome, also known as Phelan-McDermid syndrome, is characterized by developmental delays, moderate to severe intellectual disability, decreased muscle tone (hypotension), absent or delayed speech, and autism or autistic behaviors that hamper communication. and social interaction. We hypothesize that while a complete deletion of 22q13.3 causes a severe syndrome, a specific decrease in PHF21B function may cause a more subtle and specific phenotype, possibly related to social interaction. In a stress model, we report a significant decrease in hippocampal Pf21b gene expression in rats resistant to chronic restraint stress compared to rats without chronic stress. The PHF21B gene (also known as PHF4), a member of the PHD finger proteins, encodes a histone reader and is expressed in several brain regions, including the frontal cortex and hippocampus; however, its functions in the brain remain unclear. We created a Pf21b knockdown mouse model to mechanically understand how this gene regulates behavior, including social interaction and hippocampus functions.

Methods:All animal experiments were performed according to protocols approved by the State University of New York Upstate Medical University, South Australian Health and Medical Research Institute, Flinders University and University of Adelaide. Male and female mice were examined. The following approaches were used: 1) CRISPR/Cas9 technology (SA Genome Editing Facility University of Adelaide, South Australia (SA), Australia) to generate Phf21b mutant mice in which exon 4 of the mouse Phf21b gene was deleted and when the frameshift mutation generated a premature stop codon. 2) A battery of emotional, behavioral, and cognitive tests was used to determine the effects of Phf21b deficiency (Phf21bΔ4/Δ4) compared to wild-type littermate mice (WT, Phf21b+/+). 3) Standard whole-cell patch clamp was used to study long-term potentiation in CA1 pyramidal neurons of the hippocampus. 4) Transcriptome profiling was performed using hippocampal tissues, followed by differential gene expression analysis and confirmatory qRT-PCR studies. 5) Western blotting, immunohistochemistry and Golgi staining. 6) histone peptide matrix.

Results:Phf21b WT and Phf21bΔ4/Δ4 mice were in good general health. Pf21bΔ4/Δ4 expressed 60% less PHF21B than WT mice. Male and female mice showed similar changes in behavior and their pooled data was used for data analysis. PHF21b deficiency resulted in highly specific social memory deficits (increased social novelty on the 3-camera social test (P <0.01); no shortened interaction time during habituation tests on the 5-trial social memory test, and the difference in outcome was significantly smaller (P < Importantly, these animals showed no other cognitive, emotional, or memory differences. PHF21B deficiency resulted in thinner cortices (P <0.001) with fewer astrocytes (P < 0.0001) and reduced neurogenesis (DCX+ cells, P < 0.001). Pph21bΔ4/Δ4 hippocampi had decreased synaptic protein expression (less PSD95 + clusters/unit area, P < 0.001; lower PSD95 + large dots, P < 0.001). 0.01), decreased glutamatergic neurotransmission (decreased I/O ratio, P <0.001; altered LTP) and levels of GluN2B (P <0.05) and Grin2b (P <0.01).RNAseq showed that PHF21B modulates the expression of neurotransmitter genes Studies with histonep p peptides showed that PHF21B regulates transcription via H3K9ac, H3K9Me2 and CREB (cAMP response element binding protein) and interacts with H3K36me3.

Conclusions:Our results show that PHF21B regulates social memory and that reduced PHF21B function causes impaired long-term hippocampal potentiation. There are fewer groups of AMPAR subunits that express GLUR1 in the hippocampal tissues of Pf21bΔ4/Δ4 mice, resulting in decreased glutamatergic neurotransmission. We show that PHF21B is a critical upstream regulator of genes related to synaptic plasticity and acts as an epigenetic reader. Furthermore, we characterized a potentially novel interaction of PHF21B with trimethylated histone H3 lysine 36 (H3K36me3), a histone modification associated with transcriptional activation and the CREB transcription factor. Having identified a novel role for PHF21B as a regulator of social memory and analyzing the underlying neurobiology at structural and functional levels, we now propose that PHF21B may be a new candidate as a translational therapeutic target for neurobehavioral disorders.

Key words:Social and behavioral deficits, epigenetics, neuroepigenetic editing, glutamatergic transmission, AMPA glutamate receptors

Disclosure:Nothing to disclose.

Lukas Weber*, Heena R. Divecha, Matthew N. Tran, Sang Ho Kwon, Abby Spangler, Kelsey D. Montgomery, Madhavi Tippani, Rahul Bharadwaj, Joel E. Kleinman, Stephanie C. Page, Thomas M. Hyde, Leonardo Collado- Torres, Kristen R. Maynard, Keri Martinowich, Stephanie C. Hicks

Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA

Background:The locus coeruleus (LC) is a small bilateral nucleus located in the dorsal pons of the brainstem and serves as the primary site in the brain for production of the neuromodulator norepinephrine (NE). NE-producing neurons in the LC project widely throughout the central nervous system and play critical roles in arousal and mood, as well as in several components of cognition, including attention, learning, and memory. Consistent with its prominent role in a variety of central physiological and behavioral functions, the LC-NE system is strongly implicated in a number of neurological and neuropsychiatric disorders. Importantly, LC-NE neurons are very sensitive to degeneration in both Alzheimer's disease and Parkinson's disease. However, despite its prominent involvement in several critical brain functions, the small size of the nucleus and its location deep in the brainstem made full cellular, molecular, and physiological characterization relatively difficult.

Methods:Here, we used the 10x Genomics Visium spatial gene expression platform to acquire spatially resolved transcriptome (SRT) data along with histological images to characterize the spatial gene expression landscape of the LC and surrounding region (N = 5 male adult neurotypical donors , 23,387 spatial locations, 8 acquisition areas) and the Chromium Single Cell Gene Expression (snRNA-seq) single-core RNA sequencing platform to capture the transcriptome profile of single nuclei from LC-NE neurons and other neuronal cell populations and non-neuronal (N = 3 neurotypical male adult donors, 19,927 cell nuclei). Spatial regions in the SRT data containing LC neurons were annotated based on histological images and validated by confirming expression of NE neuron marker genes (TH, SLC6A2, DBH) and used for further downstream analyses, including differential expression analysis to identify genes associated with LC. and for comparison with previously identified CL-associated genes in rodents. LC-NE neurons and other cell populations in snRNA-seq data were identified by unsupervised clustering and validated by confirming the expression of known marker genes and used for analyses, including integration with SRT measurements and testing for genetic risk associations.

Results:We identified highly associated (false detection rate, FDR < 10^-3, absolute fold shift, FC > 3) and statistically significant (FDR < 0.05, absolute FC > 2) sets of genes that characterize the transcriptome profiles of human LC regions SRT samples containing known NE neuron marker genes (TH, SLC6A2, DBH) and other genes. A subset of CL-associated genes previously identified in rodents using alternative technology platforms were highly expressed in human samples. We identified a population of LC-NE neurons with unique nuclear resolution and, additionally, we identified a population of 5-hydroxytryptamine (5-HT, serotonin) neurons that had not been previously characterized at the molecular level in human brain samples. We mapped the spatial distribution of single-core populations by integrating SRT and snRNA-seq data and examined the association of genomic risk for Alzheimer's and Parkinson's disease and attention deficit hyperactivity disorder in single-core populations.

Conclusions:We generate a spatially resolved single-core gene expression atlas of the LC and surrounding region in the neurotypical adult human brain and provide a publicly available data resource containing spatially-resolved single-core data in R/ and an accessible format. from the web. bioconductor formats. This resource, which contains the complete transcriptome profile of LC-NE neurons and other cell populations within the LC region, will contribute to the understanding of neurodegenerative and other diseases, which is particularly relevant as the maintenance of neuronal density of LC-NE neurons NE is unifying cognitive decline prevents aging. 🇧🇷

Key words:Locus coeruleus, norepinephrine, spatial transcriptomics, single-core RNA sequencing, postmortem human brain tissue

Disclosure:Nothing to disclose.

Alexandria Athanason, Marcis Scroger, Noah Paperny, Andrea Liss, Florence Varodayan*

Binghamton University, Binghamton, New York, USA

Background:Norepinephrine (or norepinephrine; NE) is an important brain stress system that tightly controls cognitive and affective behavior. During periods of arousal, stress, and alcohol exposure and withdrawal, NE is released from the locus coeruleus (LC) into the medial prefrontal cortex (mPFC), where it binds to α1, α2, and β adrenergic receptors to modulate function. In particular, the prelimbic (PL) subregion of the mPFC plays critical roles in sustained attention, decision making, working and episodic memory, and coping with perceived stressful events. Unfortunately, most of these studies have focused on males. This is particularly surprising since the LC is sexually dimorphic; Females have a higher CL than males, and their CL does not sensitize them to repeated stress or alcohol exposure. Therefore, here we investigate possible sex differences in baseline mPFC noradrenergic signaling in male and female mice.

Methods:All experiments were performed with male and female C57BL/6J mice (n=10–18 per sex for each experiment). We used high performance liquid chromatography to measure baseline mPFC NE levels. Gene expression of α1 and β-adrenergic receptors was also characterized by real-time polymerase chain reaction. To assess noradrenergic function, we performed ex vivo patch-clamp electrophysiological recordings on layers 2/3 and 5 PL neurons. Finally, behavioral pharmacology experiments are currently investigating the impact of noradrenergic signaling on anxiety-like and cognitive behavior (Barnes maze, elevated plus maze, etc.). Final values ​​were tested for independent significance using 1-sample t-tests and analyzed using unpaired t-tests or one-way ANOVA with post-hoc analysis, as appropriate, using Prism software (GraphPad, San Diego, CA).

Results:There were no significant gender differences in noradrenergic signaling in the mPFC at baseline. However, there were crucial gender differences in their modulation of PL glutamatergic synapses, with NE increasing glutamate release in layers 2/3 and 5 in men, but only in layer 5 in women (all p<0.05). Behavioral studies are ongoing.

Conclusions:Therefore, we identify here important gender differences in noradrenergic influence on mPFC function that may need to be addressed in ongoing efforts to develop noradrenergic therapies to treat neuropsychiatric disorders such as alcohol use disorders and post-traumatic stress disorder. occurs under conditions of increased cognitive load (eg, stress or alcohol withdrawal) plays a role.

Key words:Norepinephrine, sex differences, mPFC

Disclosure:Nothing to disclose.

Alexander McGirr*, Donovan Ashby

Hotchkiss Brain Institute, University of Calgary, Calgary, Canada

Background:Depressive, traumatic, and other stress-related disorders are associated with widespread changes in the functional connectivity of the brain network. As it is unclear what functional connectivity changes occur during acute stress, it is not clear how they are related to the emergence of large-scale persistent network organization.

Methods:Using Thy 1-jRGECO1a transgenic mice, we repeatedly examined mesoscale cortical calcium activity in the dorsal neocortex during quiet wakefulness under different experimental conditions. Initially, the animals were photographed in a caged state, after which the animals were subjected to acute shock paw stress, a chronic variable stress protocol, acute to chronic shock paw stress, and treatment with the ant prototype antidepressant ketamine. fast. We focused on slow cortical activity (0.3-4 Hz) and cortical theta-alpha activity (4-15 Hz) to characterize functional connectivity.

Results:Compared to the home cage, acute foot shock loading induced widespread increases in cortical functional connectivity over the 4-15 Hz time range in both functional modules (t(31)=-4.66, p<0.001) and between functional modules (t (31) ) = −4.51, p < 0.001) before returning to control at 24 hours. Chronic stress induced a selective increase in functional connectivity between modules in the 0.3-4 Hz band (t(14)=-2.81, p<0.05), which was reversed after treatment with the antidepressant ketamine fast. Changes in functional connectivity induced by acute stress in the 4 to 15 Hz band were closely related to changes in functional connectivity after chronic stress and the reversal pattern of functional connectivity by subanesthetic ketamine.

Conclusions:Stress induces changes in functional connectivity, and these have specific effects that transcend spatiotemporal aspects of connectivity to link acute, chronic, and treatment effects. The mechanisms by which acute stress connectivity changes become embedded in a lower temporal band over time have yet to be determined.

Key words:Functional connectivity, acute stress, chronic stress

Disclosure:Provisional Patent: Patent (Own)

Gabriela Lopez*, Louis Van Camp, Talia Lerner

Feinberg School of Medicine, Northwestern University, Chicago, Chicago, Illinois, EUA

Background:Behavioral adaptations to aversive stimuli are essential for survival. The mesoaccumbal nuclear circuit, which includes dopaminergic neurons in the ventral tegmental area (VTA) that project to the nucleus of the nucleus accumbens (cNAc) and their projection targets within the cNAc, has been extensively studied for its role in motivation, signaling associations , and goal - directed segmentation . Maladaptive behavioral changes in this cycle are associated with psychiatric disorders such as chronic pain, addiction and depression. Although the central mesoaccumbal circuitry has most commonly been implicated in reward processing, its role in aversive processing and in various aversion scenarios remains unclear. Previous studies have extensively examined dopamine release in response to unavoidable aversive stimuli, finding conflicting results. While it is important to understand direct responses to aversive stimuli, it may be more ethologically relevant to study how an animal behaves when given the opportunity to avoid an aversive stimulus, which can be accomplished with instrumental tasks. Furthermore, many previous studies have examined dopamine release and cNAc neuron activity separately, making it difficult to determine how dopamine cNAc affects the local dynamics of the cNAc circuit. I used Pavlovian and instrumental behavioral paradigms in conjunction with multicolor fiber photometry to identify how variations in the dynamics of mesoaccumbal nucleus circuitry can predict differences in aversive processing.

Methods:To study aversive processing in the central mesoaccumbal circuit, I used two shock-paired behavioral tasks: active avoidance, an instrumental behavior that allows mice to avoid shock, and avoidance shock. I used fiber photometry to record dopamine release in cNAcs expressing a fluorescent dopamine sensor (pAAV9-CAV-dLight1.3b). To record the activity of striatal projection neurons (SPNs) that express either the D1 dopamine receptor (D1R) or the D2 dopamine receptor (D2R), I also injected a virus carrying a Cre-dependent fluorescent calcium sensor (pAAV1-CAG- FLEX-NES-jRCaMP1b). in the cNAc of D1-Cre and A2A-Cre mice, respectively. Next, fiber optic implants were placed over the injection site and neural activity was recorded while the mice moved freely. During the active avoidance task, which used a dual-chamber chamber, mice received light and sound signals before an electric shock was administered to the paws in the chamber they were in, and the mouse had 5 seconds to move to run to inside the chamber. the opposite chamber prevents electrocution. After 5 s, a 0.4 mA shock was initiated and lasted for 25 s or until the mouse moved to the opposite chamber. There were two behavioral scenarios in this task: 1) Avoiding Shock, where the mouse moved to the opposite camera before the onset of shock (<5 s), and 2) Escaped Shock, where the mouse moved to the opposite camera after the shock discharges in motion from the chamber opposite the shock. Shock initiated (>5 s). Mice were tested on this task for 7 days, 30 trials per day. Finally, the mice were subjected to an inevitable shock task, in which a 5-second sound and light signal predicted a 5-second 0.4 mA shock that they could not avoid or escape. Mice were tested on this task for 1 session consisting of 10 trials.

Results:After 7 days of active avoidance testing, mice learned to avoid ≥80% of shocks. Dopamine release from cNAc increased during avoidance and escape events and at the time of firing cessation. The magnitude and duration of these increases changed as the animals learned the avoidance task. In contrast, dopamine release was reduced in response to shock and predictive signs of shock. This dynamic varied in magnitude depending on whether the mouse was avoiding the impact or fleeing. At SPNs D1 and D2, I observed increases in activity followed by sustained decreases in response to avoidance and escape events. SPNs D1 and D2 also showed increased activity in response to shock and shock prediction signals. SPN D1 and D2 often showed similar activity patterns, rather than opposite activities that would be predicted by their different dopamine responses. During the inevitable shock session, dynamics of dopamine release and SPN activity differed in magnitude and duration in response to shocks and predictive shock signals compared to active avoidance tests and within inevitable tests in a given session .

Conclusions:My data illustrate how cNAc dopamine release dynamics and D1 and D2 SPN activity differ in response to different aspects of Pavlovian and instrumental aversive learning. These data also reinforce the importance of using more complex and ethologically relevant behaviors to better understand how central mesoacumbal circuits are involved in neural and behavioral adaptations to aversive stimuli. I am currently studying how the activity of this circuit is affected after nerve injury as a chronic pain model to understand how pain can modulate aversive processing, which may contribute to opioid addiction and depression. Understanding basic processes important for survival, such as B. aversive learning, will allow us to better understand what can go wrong under conditions where aversive processing is dysregulated, such as. B. in chronic pain, addiction and depression.

Key words:Dopamine, fiber photometry, mesolimbic circuits, active avoidance, nucleus accumbens

Disclosure:Nothing to disclose.

Jonathan Vogelgsang*, Kiely French, Anna Lally, Kerry Ressler, Sabina Berretta

Harvard Medical School McLean Hospital, Belmont, Massachusetts, Estados Unidos

Background:Suicide is one of the biggest concerns, but it is also described as extremely distressing for patients in psychiatry with all different psychiatric illnesses. Emotional dysregulation, such as depression, anxiety, and impulsivity, is one of the most important clinical features associated with suicidal behavior. However, no biomarkers clearly associated with suicide attempts have been identified to date and no common brain abnormalities have been described. As stress and its associated factors and hormones are one of the most important risk factors for mental health, we focused on corticotropin-releasing hormone (CRH), the corresponding receptor (CRH1R) and the receptor activating peptide, pituitary adenylate cyclase (PAC1R). ), focused). ) to identify common molecular patterns in suicide in different psychiatric disorders. As all these markers have been associated with emotional dysregulation, we postulate that changes in CRH, CRH1R or PAC1R expression in the amygdala are involved in suicidal behavior.

Methods:Human post-mortem brain protein lysates from the central nucleus of the amygdala of 150 brain donors including controls, patients with major depressive disorder (MDD) and post-traumatic stress disorder (PTSD) were analyzed. Of these 150 donors, 19 donors died by suicide, while 99 died of natural or accidental causes, and 32 were classified as "undetermined". 52% of donors were women. Donors of four different races were included: Caucasian, Asian, Hispanic and African American. Western blot analysis was performed using antibodies raised against CRH, CRH1R and PAC1R. Demographic information such as age, gender, postmortem interval (PMI), and clinical information about medications, medical history, or substance abuse were included in the analysis using multiple linear regression models and elastic network analysis.

Results:Using a regression model that includes diagnosis, suicide, and gender, we found that donors diagnosed with MDD had lower levels of CRH (p=0.014) in the central amygdala. Donors who died by suicide had significantly higher levels of CRH compared to donors who died from natural or accidental causes (p=0.024). Gender did not affect CRH levels in the central amygdala. No associations were observed between primary diagnosis, suicide or gender and PAC1R or CRH1R levels. We also performed a net elastic regression analysis to include and control for all available covariates (n = 58) and use imputations (m = 1000) to account for missing values. We calculated a pseudo p-value as a proxy for significant associations between a covariate and protein measurements. Death by suicide (p < 0.000) and childhood trauma (p = 0.019) were associated with elevated levels of CRH, while a primary diagnosis of MDD (p < 0.000), asthma (p = 0.019) and history of military service (p = 0.019) were (p<0.000). = 0.069 ) lead to a decrease in CRH levels in the central amygdala. Smoking, BMI, hypothyroidism (all p <0.000) and primary diagnosis of MDD (p =0.008) were strongly associated with reduced levels of PAC1R in the central amygdala, while PMI (p <0.000) and use of antipsychotic medications (p = 0.008) = 0.063) lead to an increase in PAC1R levels.

Conclusions:These results indicate that CRH may be a key component in suicidal behavior. This study proposes to further investigate the role of CRH and its related signaling pathways for use as biomarkers, but also to try to modify these circuits to treat patients with suicidal thoughts or attempts.

Key words:Suicide risk factor, CRH, MDD, PTSD

Disclosure:Nothing to disclose.

Nicholas Murphy*, Marijn Lijffijt, Sidra Iqbal, Dania Armaneh, Nithya Ramakrishnan, Brittany O'Brien, Amanda Tamman, Lynnette Averill, Sanjay Mathew, Alan Swann

Baylor College of Medicine, Houston, Texas, EUA

Background:Suicide is the leading cause of trauma-related deaths in the United States, surpassing car accidents and homicides. Although often associated with depression, there is increasing evidence that suicide attempt (SA) is the result of transdiagnostic mechanisms. Delineating potential mechanisms is a critical challenge because many suicides are first attempts and suicidal ideation and impulsivity can fluctuate unpredictably prior to an attempt. Addressing these challenges requires 1) defining a transdiagnostic behavioral model for suicidal behavior; 2) Identify indicators of potentially suicidal behavior that do not require a prior attempt. In this investigation, we used patients who were at high risk of retrying based on their proximity to a previous medically serious AS (MSSA). Compared with people with no history of AS, people with MSSA have an increased risk of all-cause mortality up to 10 years after AS. This appears to be related to increased arousal and behavioral sensitization (BS), predisposing to impulsive behavior and a decreased tendency toward self-preservation. Thus, we examined self-reported behavioral measures of arousal, impulsivity, and potential sensitization in stabilized MSSA subjects compared to diagnostic controls. We focus on connections between long-term (sensitization) and short-term (impulsivity, symptoms, arousal) regulation of action.

Methods:We recruited 28 transdiagnostic outpatients at high risk for AS, defined as MSSA in the past year (high risk, HR) and 23 age- and symptom-matched outpatients with no history of MSSA (low risk, LR). MINI-based psychiatric diagnoses; The severity of affective, anxiety and psychotic symptoms was measured using the SADS-C questionnaire (Schedule for Affective Disorders and Schizophrenia – Change), developed to measure these symptoms simultaneously. Fifty patients reported symptoms consistent with a major depressive episode, anxiety symptoms were present in 45%, bipolar 35%, PTSD 41%, psychotic disorders 13%, BPD 4%, OCD 3.9%. All patients completed clinical and behavioral assessments; 21 HR and 11 LR patients completed combined clinical, behavioral, and neurophysiological tasks. Clinical and behavioral analysis focused on 1) clinical symptoms, 2) aggressive behavior, 3) impulsivity, 4) sensitizing behavior. Risk group comparisons used independent-sample t-tests and Cohen's D effect sizes. Correlations with Beck's SSI-W were determined in all subjects to assess associations with risk factors and suicidal ideation. Only HR subjects had a history of suicide attempts, but we addressed the frequency and specificity of the SI allowing it in both groups.

Results:Groups were assigned based on symptom severity (SADS-C) and subjective self-reported symptoms (Internal State Scale (ISS)). Behavioral analysis revealed a longer history of aggressive behavior (p = 0.004, d = 0.87) and provoked aggressive behavior (PSAP, p = 0.02, d = 1.29), but no current aggressive behavior (MOAS) . Trait (Barratt Impulsivity Scale, UPPS) and condition (Immediate Memory Task (IMT)) did not differ significantly between groups in subdomains. However, Cohen's d effect sizes showed trends towards correct IMT detections (p = 0.059, d = 0.5; impulsivity state). History of abuse was significantly higher for physical abuse in RA patients (p=0.04, d=0.6) with a tendency to sexual abuse (p=0.055, d=0.53). CAPS-5 scores did not differ between groups in all domains. Cumulative lifetime exposure was highest for HR (p = 0.04, d = 0.67). HR patients also showed a stronger history of alcohol use disorders (Addiction Severity Index) than LR patients (p = 0.01, d = 0.69).

Beck's worst suicidal tendencies (SSI-W) correlated significantly with a broad pattern of clinical and behavioral scores. SSI-W differed significantly between HR and LR, but varied widely with significant overlap between groups. Symptoms (total SADS-C r=0.56, depression r=0.54, anxiety r=0.48), ISS (depression r=0.45, perceived threat r=0.43), aggression (PSAP r= 0.48), BIS (attention, r = 0.5 5 total r = 0.47), UPPS (lack of persistence r = 0.43), IMT (reaction time to make mistakes r = 0.48), CTQ (emotional abuse r = 0.46) and CAPS-5 (arousal r = 0.41) correlated with SSI -m

Conclusions:We examined behavioral markers of arousal and BS as indices of suicide risk using patients with MSSA in HR for recurrent AS. Our results suggest that a lifelong history of aggression, PSAP-induced aggressive responses, childhood trauma, and alcohol use are potential behavioral markers of high suicidal risk. Overall, measures related to responsiveness were more closely associated with HR, while impulsivity was more closely associated with SSI-W scores. This suggests that a sensitization-like process may predispose to HR; Overt suicidal behavior may require dysregulation of combined long-term (HR; sensitization) and immediate (SI, impulsivity) measures.

Key words:Suicide risk factors, suicide attempt, suicide mechanisms

Disclosure:Nothing to disclose.

Sheldon Preskorn*

University of Kansas, Wichita, Kansas, USA

Background:Over the past 20 years, the number of Americans who have died by suicide (currently one in 62) has increased year after year, despite public awareness of the problem and repeated attempts by several American surgeons to address it through public health approaches. . However, these have been piecemeal rather than a sustained and integrated approach.

The problem with these approaches is a biopsychosocial phenomenon with different components, including different drivers and protective factors in different individuals who die (or not) by suicide. This issue is of direct concern to many, if not most, members of the American College of Neuropsychopharmacology (ACNP) and the ACNP, who can be an important voice in advocating for a comprehensive approach to this problem.

Methods:Methods included: personal knowledge, targeted literature reviews, and conversations with people in organizations such as the NIMH Suicide Section. War on Cancer material is drawn from personal experience complemented by a literature review focused on the history of its establishment and development into a coherent organization with centralized tissue and treatment databases, cancer centers at academic medical centers in most locations. state and community cancer centers with two-way collaborative interactions, including tissue collection for biological studies, data collection from multiple clinical protocols that are run, analyzed, and then refined through a new protocol in an iterative process.

Additional literature searches focused on suicide risk factors and the medico-legal death detection system in the United States.

Results:A comprehensive consideration of the results is not possible for reasons of space, but they can be presented in more detail in the poster. The following is a top-level summary:

The War on Cancer provided a blueprint for developing a similar initiative to combat suicide in a meaningful way and demonstrated the incredible ability of such a framework to make astounding advances in the understanding and effective treatment of various types of cancer. One criticism might be that cancer allows pathological tissue to be removed and analyzed, but so does suicide using blood and, if necessary, even brain tissue.

It is important to emphasize that there are two distinct populations that commit suicide or make multiple suicide attempts. Most people who commit suicide do so on the first attempt, and about 95% of people who commit suicide do so on the third attempt. There are three psychiatric diagnoses that account for the majority of suicides. Three different psychiatric diagnoses that are well represented in the high-risk population for multiple suicide attempts. Due to space limitations, these dates will not appear here, but on the poster.

Suffice it to say: the genes in these two populations can be very different due to different underlying diagnoses, but the bottom line is that piecemeal studies involving multiple suicide attempts can create more confusion than clarity. This can be addressed in the database being established as part of this initiative and will be of great importance when analyzing genetic risk of suicide.

Briefly, the biopsychosocial understanding of suicide includes, by way of example, but not limited to, the following:

Biological data: 1) individual's DNA and epigenetic alterations; 2) messenger RNA, reflecting the state of the individual at the time of suicidal death; 4) markers of inflammatory processes and stress response at the systemic level and in the brain, particularly in the hypothalamic-pituitary axis; 6) Analysis of whole brain samples (when possible) and brain slices in high value regions where analysis of whole brain samples is not possible. These samples are analyzed to determine whether the brain circuits in these regions were damaged by concussion damage versus minor chemical damage from sound waves or chemical exposure); 7) measures of cognitive and emotional processing, if available; 8) alternative measures of impulsivity (eg, CSF serotonin and/or monoamine oxidase A (MAO-A) activity levels; 9) age and gender; 11) Comorbidities and substance abuse and/or dependence.

Psychological data: 1) The person's religious and/or philosophical beliefs, if they can be proved with reasonable certainty. For example, some religions forbid suicide while other religions exalt suicide through martyrdom; 2) the individual's sense of locus of control (ie, primarily internally or externally directed); 3) adverse childhood experiences; 4) psychiatric diagnosis(s); 5) Number of previous suicide attempts.

Social data:

How the individual functions within the nuclear family and subsequent social networks, including the individual's role within society as measured by educational attainment, marriage, and ability to function and advance in chosen occupation.

All of the above information and more as indicated by the results will be incorporated into the database and statistical models will be built to determine the highest risk combination(s), bearing in mind that there are multiple routes to accomplishing what can be suicide, which requires different predictive profiles and treatment interventions.

Conclusions:This overview provides an important pathway to understanding and being able to meaningfully deal with people at high risk of suicide. The ACNP organization and its members play a crucial role in making this idea a reality.

Key words:Suicide, Suicide Risk Factors, Database

Disclosure:Nothing to disclose.

Evan White*, Ricardo Wilhelm, Nicole Baughman, Breanna McNaughton, Rayus Kuplicki, Jennifer L. Stewart, Martin Paulus, Robin Aupperle

Laureate Institute for Brain Research, Tulsa, Oklahoma, EUA

Background:Native American (AI) communities face increased exposure to mental health risk factors due to historical and current socio-political and environmental challenges (eg, historical loss, discrimination, disenfranchisement). While this has resulted in disproportionate rates of mental illness in AI populations, there is also evidence of high levels of positive mental health in AIs. A growing body of literature shows that traditional cultural factors (eg, spirituality) can protect against mental or physical health problems. This is consistent with research conducted in the broader population, showing that religiosity is associated with a lower prevalence of deaths from despair. Furthermore, our recent work has shown that when disproportionate risk factors (eg, sociodemographic factors, exposure to trauma) are accounted for, a heterogeneous group of AIs had equivalent rates of substance use disorders (SUD) and lower rates. STB) Relating to compatible non-Hispanic white partners. Furthermore, our work showed that in the KI sample, brain activation during an inhibitory control task differed between subjects with and without STS from subjects without STS, as well as between subjects with SDS and subjects without STS. This research used a neuroscientific systems framework to examine potential cognitive and neural processes that mediate the protective effects of cultural factors in AI people. Specifically, the current study examined the potential modulation of the relationship between STS and multimodal neural markers of inhibitory control by culturally relevant protective factors (i.e., spirituality) and risk factors (i.e., thoughts of historical loss) in a sample of individuals with AI. It was hypothesized that 1) AI spirituality would reduce the impact of STB on inhibitory control and 2) that thought of historical loss would exacerbate the same relationship.

Methods:Participants were selected from an initial cohort of 60 people who identified themselves as patients with AI in the Tulsa-1000 (T1000) study and agreed to participate in a follow-up session to assess culturally relevant risk and protective factors. The T1000 study was a naturalistic longitudinal study that included assessments of mental health and substance use using the International Neuropsychiatric Mini Interview, as well as multimodal neuronal markers of inhibitory control using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) simultaneously. during a stop sign task (SST). Participants (total n = 37; no STS = 17) were included in the analysis if they completed the MINI interview and had high-quality fMRI and EEG data for SST. Neural correlates of inhibitory control included percent signal change contrast during the strong versus light stop sign test in the dorsolateral prefrontal cortex (dlPFC) and the event-related P300 potential. The Historical Loss Scale (HLS) was used to measure self-reported thought of historical loss and the Native American Spirituality Scale (NASS) was used to quantify self-reported spirituality.

Results:Linear mixed effects models (LME) were used to study the interaction of STB and NASS at dlPFC, PSC and P300 amplitudes separately. LMEs were also used to study the interaction of STB and HLS on both neural outcomes. For spirituality, the hypothesis was supported by dlPFC, where the results showed significant main effects of NASS (F= 5.144, p= 0.026) and STB (F= 12.76, p< 0.001) on dlPFC; this was put into perspective by a significant STB*NASS interaction in dlPFC (F = 13.54, p < 0.001). The results also supported the P300 hypothesis, which demonstrated a significant STB*NASS interaction (F = 4.41, p = 0.03). For historical losses, the reasoning results also supported the hypotheses. The dlPFC results showed a significant main effect of STB (F=10.65, p=0.002) qualified by a significant STB*HLS interaction (F=9.47, p=0.003). Finally, the P300 results showed a minor main effect of HLS (F = 3.23, p = 0.07) qualified by an STB*HLS interaction (F = 5.56, p = 0.02).

Conclusions:These preliminary results show that in a heterogeneous sample of adults with UA, (1) spirituality may weaken the relationship between STS and inhibitory control disorder, and (2) this relationship may be exacerbated by thoughts of historical loss. These results extend our previous work and show that inhibitory control can be an important mechanism for understanding mental health risk and protective factors for AI populations. Furthermore, the findings support a growing body of research suggesting that traditional cultural engagement can serve as a protective factor for AI communities. The current analysis is limited to an empirical cross-sectional design, a relatively small sample, and does not consider comorbidities (physical or mental health) or other mental health issues or substance use. This analysis suggests that inhibitory control may be an important neural risk mechanism and specific protective factors for AI mental health. Future work is needed to describe the anticipated and potential causal direction of these effects.

Key words:Suicide, Native Americans, protection factor, fMRI, event-related potentials

Disclosure:Nothing to disclose.

Joshua Kogan*, Ayesha Vermani, Memminger Park, Alfredo Fontanini

State University of New York an der Stony Brook School of Medicine, Stony Brook, Nova York, EUA

Background:To adapt and survive, animals must learn to distinguish between overlapping stimuli that predict different outcomes. This phenomenon, known as perceptual learning (PL), has been well described in the visual, auditory, somatosensory and olfactory systems. In particular, improved performance on LP tasks is associated with plasticity of sensory representations and decision-related neural signals. However, few studies have addressed the LP in the gustatory system. The primary sensory region for taste, known as the gustatory insular cortex (GC), encodes sensory and decision-related information, but how these representations might change with LP remains unknown. Furthermore, as part of the greater insular cortex, the GC is involved in many processes, including the homeostatic regulation of food intake and eating disorders. Therefore, the present study fills important gaps in the literature, improving our understanding of PL in the gustatory system and increasing knowledge of neural coding in a region involved in many important taste-related functions and pathologies.

Methods:The experiments are based on a new LP gustatory paradigm based on a two-alternative forced choice task. Mice first learn a distinction between sucrose (100mM) and NaCl (100mM), where presentation of sucrose in one central peak is associated with a reward in one side peak and NaCl with a reward in the other. They are then trained to distinguish between pairs of increasingly similar mixtures: 75/25 vs 25/75, 65/35 vs 35/65, and 60/40 vs 40/60 (% sucrose/% NaCl). If the animals make a mistake, they receive a punishment and no reward. Before and after training, mice are tested with a variety of mixtures to construct psychometric curves. To assess GC plasticity, cluster activity is monitored using two-photon calcium imaging. Single-neuron and population analyzes are used to identify changes in sensory and decision-related neural responses that occur in the LP.

Results:After learning, performance increased for all mixture pairs, indicating improved discrimination (n=6 mice, two-way ANOVA, learning effect p<0.001). Previous work from our lab on a similar behavioral task has shown that GC neurons encode sensory and decision-related information at different temporal epochs. Specifically, sensory information is encoded in the epoch just after the taste test, and decision-related information is encoded in the delay epoch immediately before the choice. Analysis of all registered neurons (pre-learning: 2337 neurons; post-learning: 2658 neurons) showed an increase in the proportion of neurons with delayed response (pre - 19%, post - 24% Χ2 test, p < 0.001) , but no significant change in the population responding to sampling. In the lag-but-non-sample period, after learning, the responder neurons became more selective for the next choice, and the magnitude of the difference in activity between the types of lag trials was greater. These results suggest that LP flavor may be primarily associated with improvements in decision coding. To test whether this is true at the population level, we used logistic regression to decode population selection of recorded neurons and similarly found an improvement in decoding performance after learning.

Conclusions:These results show that improved behavioral performance on a flavor LP task is associated with improved decision-related coding in GC. We confirmed this result using analyzes of neuronal activity at individual and population neuron levels. Taken together, these experiments further elucidate the GC plasticity associated with PL and provide new insights into neural processing in taste cortical islet circuits.

Key words:Insular cortex, taste, two-photon calcium imaging, mice, perceptual decision-making

Disclosure:Nothing to disclose.

Tanya Wallace*, Filomene Morrison, Philip Gerrard, Larry Ereshefsky, Michael Ballard, Joel Posener, Katherine Tracy, Jane Tiller

Neumora Therapeutics, Brisbane, California, USA

Background:The arginine vasopressin (AVP) neuropeptide system is involved in the regulation of complex social behaviors and emotional states in all species. In the brain, the vasopressin 1a receptor (V1a) is the predominant receptor subtype and has been implicated in mediating fear and threat processing. As these emotional processing deficits are present in many brain disorders, modulation of the AVP system by the V1a receptor offers a viable approach to treating these disorders. NMRA-511 has been extensively characterized in in vitro and in vivo systems and is a potent small molecule antagonist at the V1a receptor with selectivity for V1b, V2, and closely related oxytocin receptors (OTRs), as well as a variety of non-off receptors. . goal. , ion channels and transporters, and is brain penetrable and orally bioavailable in all species. Current studies were designed to evaluate the potential of NMRA-511 to modulate anxiety-related behaviors in marmosets (Callithrix jacchus) in the face of a human intruder using the Human Threat Test (HTT). In HTT, marmosets recognize the presence of a human observer as a threat and exhibit characteristic behavioral attitudes that are biochemically accompanied by elevated plasma cortisol concentrations. Furthermore, using a translational pharmacoelectroencephalography (phEEG) approach, the effects of NMRA-511 on relative potency in the spectral frequency bands in both marmosets under physiological and threat conditions were evaluated and extended to a human control population. 🇧🇷 Conditions as an exploratory measure in a phase 1 single/multiple ascending study.

Methods:Adult common marmosets (n=8) treated with NMRA-511 (0-30 mg/kg, PO) or the positive control chlordiazepoxide (CDP; 2 mg/kg, SC) were used for HTT. In a separate cohort of common marmosets (n = 6), EEG electrodes were implanted over the frontal and parietal cortices and electromyography electrodes were attached to the neck muscles. A single dose of NMRA-511 (10 mg/kg, po) or vehicle was evaluated in the marmoset phEEG study. Animals were treated according to a blinded randomized crossover design with a washout period of at least three days between treatments. Data were analyzed using RM-ANOVA (p<0.05). In the healthy control study, NMRA-511 (5, 10, 15 mg dose) or placebo was administered orally once (n=6:2; NMRA-511: placebo) and a one-system EEG was performed on 10/20 of 19 channels made. Recorded 6.5 hours. Mixed models centered on Tmax for repeated measures served as the primary analysis (p < 0.1).

Results:In the common marmoset, orally administered NMRA-511 (10 and 30 mg/kg) significantly reduced anxiety-related behaviors, as measured by a decrease in the number of threat-evoked postures observed in the HTT, without impairing locomotor activity , nor does it cause sedation. The results of the phEEG study in the common marmoset showed significant alterations specifically in the theta (4-8 Hz) and alpha (8-12 Hz) bands in physiological conditions, which worsened even more in the threatened condition. Non-significant trends were also observed in the beta band (12-30 Hz). The phEEG studies were extended to a healthy human control population and, in line with the hypotheses, the analyzes focused on Tmax showed significant increases in theta conditions (eyes open [EO] and eyes closed [EC]) and alpha (EO ) versus baseline mean line. Frontal region of the 15 mg cohort (n=6) on Day 1 compared to placebo (n=11). In addition, non-significant trends of moderate to large effect sizes were observed, indicating an increase in beta at the 15 mg dose. At the 10 mg dose (n=24), a significant increase in beta (EO and EC conditions) was observed with a moderately large and non-significant increase in theta (EO) near Tmax. Single and multiple ascending doses of NMRA-511 were safe and well tolerated in healthy participants in this study.

Conclusions:Oral administration of the V1a antagonist NMRA-511 produced anxiolytic activity without sedation in the marmoset threat assay. The same dose of NMRA-511 (10 mg/kg) that reduced anxiety in the common marmoset showed greater relative potency in the alpha and theta spectral bands with trends in the beta band in this species. Furthermore, NMRA-511 was tested in a healthy control population using phEEG as a translatable biomarker and showed similar changes in alpha and theta potency and beta band trends as in the common marmoset. These studies support the usefulness of phEEG as a translational tool connecting preclinical and human populations; and the ongoing investigation of NMRA-511 in the treatment of brain diseases.

Key words:Vasopressin-1a receptor antagonist, EEG biomarkers, anxiety, translational neuroscience

Disclosure:Therapeutic Neutral: Employees (Own), Therapeutic Neutral: Shares/Equity (Own)

Carla Pallavicini*, Lorena Llobenes, Federico Cavanna, Natali Gumiy, Maria Costa, Nicolas Bruno, Stephanie Muller, Laura Alethia De La Fuente, Paul Gilbert, Enzo Tagliazuchhi

Laboratory of Computational Cognitive Neuroscience, University of Buenos Aires, Caba, Argentina

Background:Classic psychedelics like psilocybin, N-N-dimethyltryptamine (DMT), lysergic acid diethylamide (LSD) and mescaline are known to induce profound and transient changes in consciousness. Psychedelic research has shed light on the neurophysiology of these altered states of consciousness, as well as their potential to treat various mental health disorders and promote ongoing well-being. On the other hand, the increased focus on meditation in cognitive neuroscience has led to a cross-cultural classification of standard meditation styles, validated by functional and structural neuroanatomical data. Compassion Imagery is a form of guided meditation that focuses on building a compassionate image of yourself and others to work on and develop. This practice has been linked to psychological benefits and an overall increase in markers of well-being; One of our main goals was to understand whether these benefits might be facilitated by the sense of satisfaction catalyzed by psilocybin mushrooms.

Methods:After a thorough evaluation, particularly focused on participant safety, 105 healthy volunteers were measured in this experiment. We designed an ambitious setup to cover as many dimensions of the experience and its impact as possible. Participants were divided into 4 groups: low-dose versus high-dose psilocybin and compassion versus control meditation. Physiological and activity data were collected with Fitbits 1 week before and after the day of the ceremony. In addition, fMRI scans, blood and saliva samples were collected 1-3 days before and after. A week before the ceremony, participants answered a wide range of scales and questionnaires, including personality traits, well-being and anxiety. These actions are repeated a week, 1, 3 and 6 months after the ceremony. From the day of the ceremony, we conducted individual interviews, responses to psychometric scales and EEG recordings. Volunteers then received the meditation practice suited to their group, followed by an individual interview and proceeded to their ceremony with a facilitator. We do not interact with participants during their experience. After the ceremony, participants completed a series of questionnaires to assess their experience and we concluded the event with EEG recordings, saliva samples, individual interviews and group sessions. Follow-up measures consisted of the scales and questionnaires mentioned above, as well as blood and saliva collection, which was performed 2 months after the ceremony.

Results:Preliminary results show that participants in the compassion groups performed significantly better on interoceptive constructs such as body listening and trust, as indicated by the MAIA scale (p < 0.05), and also reported having a subjective experience with greater influence of images elementary (p < 0.05). 🇧🇷 Only for the compassion group was there a difference in the subjective construct of change in meaning between high and low dose. Reported incidents of anxiety and difficult experiences occurred only in the high-dose groups and were of low incidence (<5% of participants). The interviews differed in detail between the high and low dose groups, and the EEG data also tended to differ between these groups.

Follow-up is ongoing, but we expect that the differences will become more pronounced over time and that new evidence will be found of how this combination of practices is reflected in markers of subjective well-being.

Conclusions:We were able to do a large number of measurements on a large number of participants in a combined study of psychedelia and meditation. This experience is innovative for this type of research in Latin America. We found these ceremonies to be safe for participants and the combination with meditative practices contributed to the low number of observed difficult experiences. Ceremonial psilocybin use may positively impact self-reported measures of mental well-being, mood, prosocial behavior, emotion regulation, and cognitive ability. Psychological priming with compassionate imagery practices can be a useful tool to increase the positive impact of subjective experiences, and our results show a trend in this direction.

Key words:Psilocybin, Meditation, Mental Wellness, EEG, Functional Magnetic Resonance Imaging (fMRI)

Disclosure:Nothing to disclose.

Margaret Davis*, Olivia Wilson, Ashley Wagner, Nabeel Nabulsi, David Matuskey

Yale University School of Medicine, Waterbury, Connecticut, USA

Background:Borderline Personality Disorder (BPD) is a severe psychiatric disorder associated with high morbidity and mortality and increased risk of suicide. Despite this, treatments capable of influencing the overall severity of symptoms and reducing the risk of suicide in BPD are limited. Promisingly, recent evidence has linked the kappa opioid receptor (KOR) to both BPD and suicidal behavior. In particular, autopsy studies have shown an association between KOR and suicide-related death, and animal and human studies have shown that KOR antagonists can have antidepressant, anxiolytic, and even antisuicidal effects. To date, however, associations between KOR, BPD, and suicidal behavior have not been studied directly. The aim of this study was to investigate the relationship between KOR availability, BPD and suicidal behavior in vivo using [11 C]EKAP PET.

Methods:Individuals with BPD (N =8, 4 with previous suicide attempt (SA), 4 without (NSA)) and healthy adults (HA; N=8) matched for age and sex (6 women and 2 men in each group )., and stories about smoking were recruited from the community. All participants underwent 1 MRI and 1 [11 C]EKAP PET scan and a battery of psychiatric and cognitive assessments. The radiopharmaceutical was injected in bolus and the individuals were scanned for 120 minutes. The volume of distribution (VT: the ratio of activity in tissue to that in blood corrected for metabolites) was calculated using the arterial input function. Primary analyzes focused on a circuit of 6 frontal and limbic brain regions relevant to the pathophysiology of BPD and suicidal behavior: dorsolateral prefrontal cortex (dlPFC); orbitofrontal cortex (OFC); ventromedial prefrontal cortex (vmPFC); anterior cingulate cortex (ACC); amygdala; hippocampus.

Results:ANOVA analyzes showed significant differences between groups in KOR availability (VT; p = 0.009, d = 1.85, 27% lower). In particular, differences were more pronounced in people with BPD who reported a history of AS. In particular, subjects with BPD who reported a history of AS had significantly lower KOR availability compared to BPD-NSA (p<0.001; d=1.93; 24% difference) and HA (p<0.001). 🇧🇷 d=2.24; 35% difference). Furthermore, frontolimbic KOR availability in BPD was negatively correlated with endophenotypic correlates of suicide risk in BPD, including difficulty in emotion regulation (r=-0.83), impulsivity (r=-0.80), and depressed mood ( r=-0). , 82). 🇧🇷

Conclusions:Preliminary results support a relationship between KOR, BPD and suicidal behavior in BPD. People with BPD had lower availability of frontolimbic KOR with concordant relative AH. Furthermore, BPD subjects with a history of AS had lower frontolimbic KOR availability compared to BPD-NSA and HA, suggesting a possible role for KOR as a suicide risk marker in BPD. Of clinical importance, KOR availability was negatively correlated with endophenotypic correlates of suicidal behavior in BPD, including difficulty with emotion regulation, impulsivity, and depressed mood, variables that have been shown to predict future AS as well as suicide mortality. Together, these results provide the first direct evidence of a possible role for KOR in the pathophysiology of BPD and suicidal behavior. Further evaluation of KOR targets is needed for the treatment of suicidal behavior in BPD.

Key words:Borderline personality disorder, suicide attempt, kappa opioid receptor, PET imaging study

Disclosure:Nothing to disclose.

Macarena Aloi, William Poblete, John Oldham, Michelle Patrick, David Nielsen, Thomas Kosten, Ramiro Salas*

Baylor College of Medicine, Houston, Texas, EUA

Background:Patients with borderline personality disorder (BPD) suffer from emotional and interpersonal instability and a high risk of suicide. microRNA-124-3p (miR-124) was identified as likely to be associated with BPD in a genome-wide association study.

Methods:Using TargetScan and Allen Atlas datasets, we identified brain regions where co-expression of genes likely to be modulated by miR-124 is highest and compared morphometry in these brain regions in hospitalized BPD patients (N = 111) with controls correspondents for psychiatric comorbidities (N = 111) at the Menninger Clinic in Houston, Texas. We then correlated measures of personality, intensity of suicidal ideation, and recovery from suicidal ideation with volumetrics.

Results:MiR-124 gene targets were significantly co-expressed in the left globus pallidus (GP), which was lower in BPD than psychiatric controls. In BPD, but not in controls, lower GP volume was negatively correlated with tolerability and with recovery from suicidal ideation after treatment. In BPD, but not in controls, the GP was lower in older patients than in younger ones.

Conclusions:In BPD, GP volume can be reduced by regulating miR-124 and repressing its target genes. Importantly, we identified that PG reduction can serve as a potential biomarker for recovery from suicidal ideation in BPD.

Key words:Borderline personality disorder, human epigenetics/microRNA, globus pallidus, morphometry, human brain imaging

Disclosure:Nothing to disclose.

Songjun Li*, Pauline Gabrieli, Moeko Suzuki, Omer Zeliger, Jack Demaree, Renee Cauchon, Nicole Occidental, Ziv Williams

Massachusetts General Hospital, Boston, Massachusetts, USA

Background:Compassionate behavior, or the ability to help those in need, is the cornerstone of prosocial interaction in mammals and humans. To benefit others, it is necessary for people not only to perceive others' inner states or emotions, but also to take appropriate action. For example, one should acknowledge another's suffering and take specific steps to alleviate their discomfort. However, it has been difficult to understand how mammalian neurons accurately link specific social information to such complex adaptive behavior.

Methods:We recorded the activity of individual neurons in the dorsal anterior cingulate cortex (dACC) and anterior insula (AI), two brain regions involved in prosocial behavior, while mice directly controlled the experience of a close conspecific in real time. This new task made it possible to separate the animal's own actions from the identity and experiences of the other. Furthermore, we use chemogenetic tools to inhibit or stimulate the dACC-AI circuitry to modulate these behaviors.

Results:We found that wild male mice consistently chose to reduce the aversive experiences of familiar but not unfamiliar partners, actions not observed when visual and olfactory cues were blocked. KI cells preferentially encode task-related information, including partners' social identity and specific experience, whereas ACC cells preferentially encode information about helping their partners. While information about the experiences of others can be deciphered primarily from KI activity, information about the animal's prosocial actions can be deciphered primarily from dACC activity. Chemigenic excitation of IA-to-dACC projectors, but not dACC-to-IA projections, increased compassionate behavior, whereas inhibition of dACC-to-IA and IA-to-dACC projectors increased compassionate behavior toward partners diminished confidence.

Conclusions:Our data suggest that mice exhibited consistent sympathetic behavior toward family members where there is information sharing within insular prefrontal circuits. In particular, the AI ​​appears to convey certain social information to the dACC, while the dACC directs compassionate decisions based on the AI's information. Taken together, these results identify a putative insular-prefrontal circuit that controls compassionate behavior and a mechanism that may allow insular neurons to direct specific social actions through prefrontal control.

Key words:Social and behavioral deficits, empathy, decision making, mice, in vivo single device electrophysiology

Disclosure:Nothing to disclose.

Ruixiang Wang*, Zeru Peterson, Nagalakshmi Balasubramanian, Kanza Khan, Gabrielle Bierlein-De La Rosa, Thomas Nickl-Jockschat, Catherine Marcinkiewcz

University of Iowa, Iowa City, Iowa, USA

Background:Deficits in social functioning are a common feature of several mental disorders, including schizophrenia and autism spectrum disorders. However, the neural mechanisms underlying these deficits remain unclear due to the dynamic and complex nature of social behavior. Combining 3D imaging with immunological labeling (iDISCO), chemogenetics and functional magnetic resonance imaging (fMRI) methods, the present study aimed to map the altered neural network associated with social deficits in a mouse model.

Methods:Male C57BL/6J mice were treated with ketamine (3 mg/kg, i.p.) or vehicle (0.9% saline) for 10 days. Twenty-four hours after the last treatment, they were given a three-chamber sociability test or an equivalent two-chamber empty test. Their brains were then all immunostained with a c-fos antibody, washed with dibenzyl ether and photographed under a light sheet microscope. As a marked reduction in c-fos activation in the lateral septum (LS) was observed after chronic exposure to ketamine, we tested whether the decrease in activity in the LS was necessary and sufficient for social deficits by manipulating the chemogenetics of SL neurons. Furthermore, to investigate the functional connectivity emanating from the LS that regulates social behavior, we performed fMRI chemogenetic mapping of the LS neuron network.

Results:Chronic exposure to ketamine resulted in a significant reduction in social interaction (p<0.001), which was associated with an attenuated induction of c-fos in the LS (p<0.05), shown in the iDISC images. Therefore, we transduce naïve C57BL/6J mice with a Gq-coupled DREADD (hM3Dq-mCherry) into LS and then treat them with chronic ketamine. 24 hours after the last ketamine administration, clozapine N-oxide (CNO; 3 mg/kg, i.p.) mediated activation of Gq-DREADD in SL has been shown to rescue social isolation induced by chronic exposure to ketamine. 🇧🇷

To investigate whether inhibition of previously activated LS neurons during social interaction was sufficient to induce social deficits, we inserted a Cre-inducible Gi-coupled DREADD (DIO-hM4Di-mCherry) into the LS of microinjected fos-iCreER mice. After a social interaction session, these mice received 4-OH tamoxifen (10 mg/kg, i.p.) to induce Cre-mediated recombination and DREADD expression in active neuronal populations. Four weeks later, we performed the sociability test 45 minutes after a CNO injection. Inhibition of LS neurons by Gi-DREADD has been shown to result in reduced social interaction (p<0.001).

In eGFP-L10A mice microinjected with the hSyn-Cre virus into the SL, we observed strong eGFP expression in the hippocampus, which consequently represents an important projection area of ​​SL neurons. Therefore, we examined this circuit with fMRI. Fos-iCreER mice were transduced with a Cre-inducible Gq-coupled DREADD (DIO-hM3Dq-mCherry) in LS. They were then subjected to a social interaction session and injected with 4-OH tamoxifen. Four weeks after CNO administration, an fMRI was performed. There was a trend towards a decrease in functional connectivity between the SL and the hippocampal formation (p < 0.09).

Conclusions:As a valid mouse model for studying social deficits, chronic exposure to ketamine leads to hypoactivation of LS neurons, which is necessary to induce social isolation. Furthermore, inhibition of LS neurons activated in social interaction is sufficient for the development of social deficits. Furthermore, it was previously discovered that most LS neurons are GABAergic and therefore inhibitory in nature. Therefore, activation of LS neurons leads to a tendency to reduce connectivity with the hippocampus, an important projection area of ​​LS neurons.

Key words:Social deficits, subchronic ketamine model, lateral septum, iDISCO mapping, fMRI

Disclosure:Nothing to disclose.

Robert Mealer*, Richard Cummings, Jordan Smoller

Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, EUA

Background:Schizophrenia is a severe and highly heritable neuropsychiatric disorder. Recent studies have shed light on the complex genetic architecture of the disease, identifying over 270 common variants and 10 rare variants that cause significant changes in risk. However, given the polygenic inheritance pattern and clinical heterogeneity of schizophrenia, treatment development remains a significant challenge. One pathway with converging evidence for a role in the pathogenesis of schizophrenia is impaired glycosylation, the enzymatic binding of carbohydrates to proteins and lipids to regulate their function.

Methods:To provide a broad framework for understanding the relationship between schizophrenia and glycosylation, we will review the results of several recent, well-substantiated, peer-reviewed studies. The main objectives are: 1) to explore publicly available schizophrenia GWAS data and exome sequencing data for glycosylation enzymes and glycosylation-regulated proteins (glycoproteins); 2) Describe post-mortem studies of schizophrenia that examined brain glycoproteins; 3) Summarize animal models of schizophrenia risk genes involved in glycosylation.

Results:In line with the GWAS findings, the list of glycosylation enzymes unequivocally associated with schizophrenia continues to grow, with nearly a dozen prioritized genes involved in different domains of protein glycosylation. Of the rare coding variants, it is known that the protein products of the 3 genes directly involved in neurotransmission (GRIN2A, CACNA1G and GRIA3) are regulated by glycosylation. Post-mortem studies have identified alterations in the levels of glycoproteins and their transcripts in different glycosylation pathways, although these findings may be due to the environment in which one lives with schizophrenia. Finally, mouse models of genetic risk for schizophrenia, including our work with the common variant SLC39A8-A391T, demonstrate alterations in brain glycosylation in glycoproteins that are genetically and functionally involved in the pathogenesis of schizophrenia, including cell adhesion molecules and neurotransmitter receptors.

Conclusions:Several lines of evidence support a role for altered protein glycosylation in the pathogenesis of schizophrenia. As inborn disorders caused by severe mutations in many of the same genes can be effectively treated by targeted supplementation of enzyme precursors and cofactors, the glycosylation pathway may represent a new opportunity for therapeutic development in schizophrenia. Furthermore, we hope this information will help researchers better understand and address protein glycosylation in their studies of the pathogenesis of schizophrenia.

Key words:Schizophrenia (SCZ), genetics, glycosylation

Disclosure:Nothing to disclose.

Melanie Grubisha*, Nicholas Lehman, Ryan Salisbury, Susan Erickson, Gregg Homanics, Matthew MacDonald, Robert Sweet

University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Background:The onset of gray matter reduction during adolescence, along with postmortem findings of smaller dendrites, has been consistently demonstrated in schizophrenia (Sz). Once formed, dendrites are largely stable structures due to competitive growth and signs of regression. Understanding the pathways involved in this dynamic homeostasis is key to designing interventions aimed at dendritic regression in Sz. We have recently shown that OMGp, a Nogo receptor 1 (NGR1) ligand, activates a signaling pathway that alters this balance and leads to dendritic regression. This pathway requires active domain of KAL9. Activation of a KAL9 gain-of-function mutation (KAL9-PT) resulted in dendritic regression in adolescence, coinciding with the time of the normal developmental increase in pGMO expression and the onset of clinical symptoms in SZ. We hypothesize that activation of OMGp/NGR1/KAL9 leads to changes in phosphorylation of mediators downstream of the dendritic structure, some of which are Sz risk genes.

Methods:We used OMGp stimulation in dissociated cortical culture followed by phospho enrichment and mass spectrometry to identify the course of downstream signaling events using phosphoproteomics. Crispr/Cas9 was used to create a floxed OMGp mouse for developmental studies of OMGp KO in cortical dendritic architecture.

Results:Phosphorylation is a post-translational modification capable of regulating the function of a protein, activating or inactivating it, depending on the site of phosphorylation. Proteins with significantly greater phosphorylation after pGMO treatment included Trio and Cacna1g, both of which have excess loss-of-function mutations in SZ that are genome-wide significant. Loxp sites were successfully inserted flanking the OMGp gene without altering OMGp expression levels prior to Cre recombination. Dendritic architecture studies in OMGp-KO mice are ongoing.

Conclusions:We identified an overlap between pGMOp signaling in adolescence and genetic risk for Sz (ie, Trio and Cacna1g). Using mouse models, we will next determine whether targeting these mediators in vivo during the normative increase in pOMG activity in adolescence can be used to prevent or reverse dendritic regression. These results offer a new opportunity to develop new targeted therapies.

Key words:Dendrites, schizophrenia (SCZ), youth

Disclosure:Nothing to disclose.

Madeline Scott*, Wei Zong, Kyle Ketchesin, Marianne Seney, Bokai Zhu, George Tseng, Colleen McClung

University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA

Background:Schizophrenia (SS) is a chronic neuropsychiatric disorder associated with cognitive dysfunction and disrupted circadian behavior. Consistent with circadian rhythm dysfunction, studies have shown abnormal peripheral gene expression of circadian clock genes and changes in rhythmic expression of hormones in people with CS. However, the characterization of molecular rhythm patterns in the human brain is just beginning. Our laboratory recently compared a specific set of diurnal rhythmic transcripts in individuals with SZ in a cohort with no history of psychiatric illness (non-psychiatric; NP) using rhythmic analysis of RNA sequencing data (RNA-seq) from the observed dorsolateral prefrontal cortex . (DLPFC), a region associated with executive dysfunction and strongly implicated in SZ. Pathway analysis showed that genes that acquired a 24-hour rhythm in SC were associated with mitochondrial