2021 Fellows' Scientific Training Day
NIMH Intramural Research Programs
September 24, 2021 Anxiety-related striatal connectivity in adolescence and adulthood
E. Weiss, C. Gaillard, B. Benson, D. Pine, and M. Ernst
Introduction
Adolescence is a period marked by a steep increase in the incidence of anxiety. Research suggests that the striatum plays a role in in attention, learning, and motivation, which all show perturbations in anxiety disorders. Given the importance of development and the relative paucity of clinical developmental neuroimaging studies in anxiety, we exploited a large sample of adults and adolescents characterized as either healthy or clinically anxious. Our goal was to examine differences of anxiety-related striatal connectivity deficits between adolescence and adults. We used resting state fMRI data, which provide the basic level of communication of striatal regions with key functional regions.
Method
Adolescents (44 patients, 63 healthy, age range: 8-18 years) and adults (36 patients, 88 healthy, age range: 18-44 years) completed a resting state scan. All participants were assessed for psychiatric morbidity via KSADS for adolescents and SCID-I for adults. Participants completed questionnaires including Behavioral Inhibition and Activation Scale (BIS/BAS scale), Fear of Negative Evaluation (FNE), and State-Trait Anxiety Inventory (STAI). A General Linear Model (GLM) analysis was run in AFNI with Age and Diagnosis as between-subject factors controlling for scanner, sex, and IQ. Spearman correlation analyses explored brain-behavior associations.
Results
For this presentation, we focus on the ventral caudate because of its role in motivation, emotion, and cognition and we refer to this connectivity as "iFC". The Age by Diagnosis interaction was significant on the iFC between the ventral caudate (VC) and dorsolateral prefrontal cortex (dlPFC).
There was a significantly different pattern in adolescents (t(223) =-2.89, p =0.004) and adults (t(223) =3.41, p =0.002) when comparing anxiety patients to healthy volunteers. For adolescents, the iFC was significantly lower in patients (M= 0.076, SE= 0.020) than in healthy controls (M =0.146, SE =0.017). The adults showed the inverse pattern: the iFC was significantly higher in patients (M =0.154, SE =0.021) than in healthy controls (M =0.067, SE =0.014).
When parsing out the two-way interaction by Diagnosis, iFC was significantly higher in anxious adults compared to anxious children (t(223) =2.65, p =0.009), while it was significantly lower in healthy adults compared to healthy children (t(223) =-3.84, p < 0.001).
In adults, the iFC was positively correlated with BIS (rs =0.24, p =0.01), FNE (rs =0.20, p =0.02), and STAI-State (rs = 0.29, p < 0.001). In adolescents, the iFC was negatively correlated with BIS (rs = - 0.23, p =0.02). Additionally, the strength of these associations differed significantly (BDI: z =3.52, p < 0.001; FNE: z = 2.46, p =0.01) between adults and adolescents.
Discussion
Collectively, the reduced connectivity strength in anxious compared to healthy adolescents might represent a delayed maturation of brain regions involved in cognitive control and attentional regulation that govern goal-oriented behaviors. Additionally, the stronger connectivity observed in anxious compared to healthy adults might reflect a compensatory mechanism to alleviate dysfunctional cognitive-emotional processing. Future research should further explore such potential compensatory mechanism that comes on line with maturation, and seek ways to strengthen its efficiency. Acute vs constitutive effects of PACAP gene knockout on behavior, physiology, and the transcriptome
D. Bakalar, S. C. SWEAT , G. L. DROSSEL , S. Z. JIANG , B. S. SAMAL , N. STROTH , W. XU , L. ZHANG , H. ZHANG , L. E. EIDEN
Effects of gene loss in neuropeptide knockout animals are often interpreted as indicating that the peptide and its receptor(s) are required for the physiological or behavioral responses elicited in wild-type mice at the time of experimental examination. These interpretations presume that peptide/peptide receptor gene deletion affects only the expression of the peptide/receptor itself, and therefore impacts physiological events only at the time at which the experiment is conducted. Here, we show that there is a cohort of genes whose basal expression is affected by constitutive knock-out of the Adcyap1 gene, coding for the neuropeptide PACAP, in C57Bl6/N mice (constitutively PACAP-Regulated Genes, or cPRGs). We show a separate group of genes whose expression in response to physiological challenge, in adults, is altered or impaired in the absence of PACAP expression (acutely PACAP-Regulated Genes, or aPRGs). We also identify a behavioral consequence of Adcyap1 gene loss (repetitive jumping) which does not phenocopy in PACAP receptor (PAC1) knockout mice and does not occur upon tissue-specific postnatal knockout of Adcyap1, suggesting a developmental role of PACAP mediated by something other than its canonical receptor . We are currently using whole-brain clearing in combination with immunostaining for the immediate early gene c-fos to identify the brain locus or loci activated during repetitive jumping, and a conditional whole-brain knockout of Adcyap1 to identify the critical period for PACAP acting to prevent the development of repetitive jumping. Distinguishing constitutive and acute transcriptomic effects of neuropeptide deficiency on physiological function and behavior in mice reveals alternative mechanisms of action, and changing functions of neuropeptides, throughout the lifespan. Assessing the Early Impact of the COVID-19 Pandemic on families with Children with Motor Impairments: Access to Therapies and Well-being
S. Francis, E.N. Sutter, DPT*, L.S. Francis, MS, D.H. Lench, PhD, S.T. Nemanich, PhD, L.E. Krach, MD, T. Sukal-Moulton, PhD, DPT, B.T. Gillick, PhD, MSPT, PT
Objectives: On March 11, 2020 the World Health Organization declared COVID-19 a global pandemic. Given this historical occurrence, we took the opportunity to investigate the impact of a pandemic event on families with children with motor impairments. Our study investigated the impact of the early "phase" of the pandemic and initial U.S. lockdown on access to rehabilitation therapies and the subsequent impact to the physical and mental well-being of children with motor impairment and their caregivers (Sutter et al, 2021).
Design: Caregivers of children younger than 18 years old with childhood-onset motor impairment (primarily cerebral palsy) completed an anonymous survey between May 5 and July 13, 2020. This time frame included the early "phase" of the pandemic and the initial associated lockdown in the U.S.
Results: The survey was completed by 102 participants in three Midwest-based national databases and registries. Before the pandemic, 92 of 102 children (90%) were receiving one or more therapies; at the time surveyed, 55 children (54%) were receiving any therapies (P < 0.001). More than 40% of the sample reported increased child stress, decreased physical activity, and/or decline in mobility/movement. Participants who reported a decrease in number of therapies at the time surveyed more frequently reported a decline in child's mobility (P = 0.001) and increased caregiver stress (P= 0.004). Caregiver stress demonstrated a moderate positive correlation with caregiver burden (rho = 0.508, P <.001) and child stress (rho = 0.444, P <.001). Additionally, five qualitative themes were identified from open-ended question responses related to therapy access and well-being.
Conclusions: As assessed during the early phase and initial lockdown of the COVID-19 pandemic, access to pediatric rehabilitation therapies was disrupted. Within our survey group, disrupted access was associated with changes in child and caregiver physical and mental health. Child and caregiver feedback are important contributors to the optimization of service delivery, including telehealth modalities, during this pandemic and other future access challenges.
* - denotes primary author of Sutter et al, 2021 Reconfiguration of Functional Brain Networks During an Ecologically-Valid Fear Induction Task in Healthy and Anxious Youth
J. Galbraith, G. Ringlein, J. Linke, D. Pine, R. Abend
Background
Pathological anxiety is characterized by excessive anticipatory fears of potential threat and typically emerges in later childhood. Clarifying the neurobiological mechanisms generating threat-anticipatory fears in youth could inform early diagnosis and intervention efforts. Adolescence is a critical period for brain maturation, involving reorganization of localized and network-level connections. Basic neuroscience studies reveal changes in distributed brain regions during threat anticipation, underscoring the need for a network-based approach.
Recently, a graph-theoretical approach has been utilized in brain connectomics. This method assumes that the brain is comprised of subnetworks, known as modules, comprised of brain regions (nodes) and their connections (edges). Prior work focusing on efficiency has suggested that a healthy brain maintains a critical balance between integration and segregation to maximize processing and communication, while a faulty balance may underlie psychological disorders. However, few studies have examined how networks reconfigure following presentation of emotional stimuli, typically during rest. Importantly, no study examines reconfiguration during the anticipation of threat.
Due to practical and ethical concerns, many neuroimaging studies are restricted to resting state or tasks with static, non-potent stimuli, producing low reliability in inducing neural responses and limited generalizability. Our group has begun to address this shortcoming by utilizing a naturalistic movie to assess emotional responding while inducing robust anticipatory-fear.
In this study, by using a short, animated movie to ecologically induce fear in conjunction with application of graph theory on functional imaging data, we hope to better understand if and how anxiety impacts processing efficiency during anticipation at the circuitry level, aiming to identify novel therapeutic targets.
Methods
48 subjects aged 9-17 (F/M=30/18, age M(SD)=13.77(2.42), Anxious/Healthy=20/28) underwent a 9-minute resting state scan, followed by a 7-minute animated film intended to induce anticipation through threat ambiguity . Neuroimaging data were preprocessed with FMRIPREP. We used a 116 node parcellation scheme (100 cortical parcels, 16 subcortical regions) to extract timecourses during rest and the movie. We calculated functional connectivity as Pearson correlations. Graph metrics of interest were the modularity index (Q), with higher Q signifying more segregated information processing, and local and global efficiency, describing parallel information processing capacity among neighboring nodes or the whole brain. Brain network metrics were compared with paired t-tests using permutation testing and controlling for the number of tests. We collected self-reported anxiety severity using the Screen for Child Anxiety Related Disorders (SCARED-C,-P), and Skin Conductance Response (SCR) as a physiological measure of fear response.
Research Questions
1. Does brain functional network modularity change during induced threat anticipation?
2. Does the local efficiency change during induced threat anticipation in healthy and anxious youth? 3. Is this network modularity during each condition correlated with anxiety severity or physiological fear response?
Hypotheses
Based on prior work, I expect the modularity to increase during threat anticipation, compared to rest. Further, I hypothesize that the local efficiency of these modules will increase during threat anticipation, and that these metrics will be negatively correlated with anxiety severity. Pandemic Related Distress in the LGBTQ Population
A. Emich
The COVID-19 pandemic has led to increased psychological distress for many, as evidenced by heightened levels of depression, anxiety, and stress during the pandemic. One group that may be particularly vulnerable to these effects is the lesbian, gay, bisexual, transgender, and questioning (LGBTQ) population. Compared to heterosexual and cisgender people, sexual minorities are more likely to experience depression, anxiety, and suicidality (Ploderl & Tremblay, 2015). Members of the LGBTQ population also tend to have lower incomes, and they are more likely to work in the service industry, which puts them at higher risk of losing their jobs during the pandemic (Whittington, Hadfield, & Calderon, 2020). Furthermore, stay-at-home orders may prevent LGBTQ people from accessing important community resources that help maintain mental health, such as support groups. In light of these vulnerabilities, the current study seeks to assess whether LGBTQ identity predicts greater general distress and pandemic-related distress during the COVID-19 pandemic. Participants in the U.S. (N=3432) completed an online questionnaire battery May 2020-March 2021. Questionnaires assessed anxiety, depressive symptoms, general distress, pandemic-specific distress, psychiatric diagnoses, and demographics. Pandemic-specific distress was measured using several items which assessed worry about COVID in general, stress from maintaining social distancing, worry about infection (self and others), and worry that the pandemic would impact their mental health. We expect that those identifying as LGBTQ, compared to those who do not, will experience greater general psychological distress and greater pandemic-specific distress. These results would support increased efforts to treat mental health issues arising in the LGBTQ population specifically during the pandemic. However, preliminary results suggest that although those identifying as LGBTQ experience greater general distress during the pandemic compared to controls, they do not exhibit greater pandemic-specific distress. Future research should examine why greater general distress in this group does not extend to greater pandemic-specific distress.
Controlling brain state with EEG-neurofeedback
H. Gura & Feuer, Lysianne Beynel, Zeynab Rezaee, Tom Radman, Bruce Luber, Sarah H. Lisanby
Noninvasive brain stimulation such as transcranial magnetic stimulation (TMS) has been found to be only moderately effective in treating psychiatric disorders (Slotema et al. 2010). Besides the stimulation parameters used, subject-dependent factors could also be a potential explanation for this. Silvanto et al. 2008 found that TMS effects depend on the immediate brain state during stimulation. Controlling brain state while applying TMS therefore could reduce inherent variability in TMS effects and enhance its efficacy (Luber et al. 2017). EEG neurofeedback is a potential tool for controlling cortical activity and changing the power of targeted EEG bands (Rogala, et al. 2016). In this study, we tested whether brain activity could be controlled by using EEG-NF during a happy memory recall task. Based on previous work, we hypothesized that performing EEG-NF would induce left-right frontal alpha asymmetry (FAA). If so, our next step will be to test whether this NF-controlled state could help reduce the variability in TMS-induced EEG responses.
Twelve healthy volunteers between 18 and 65 years old, participated in this 3-day study. During the first visit, participants generated 7-10 positive memories. The second day was an EEG-NF practice session during which FAA signals were obtained via a 64-channel EEG cap placed according to the 10-20 system. The FAA of ongoing signals from the frontal electrodes of interest (F3 and F4) were computed in real-time and presented as a vertically moving bar on a computer monitor in front of the participants. Participants were instructed to maximize the height of the bar (i.e., increase the asymmetry) by focusing on the positive memories previously recalled. On the third day, participants received single-pulse TMS during EEG-NF or while watching a fixation cross (data in preparation).
To test whether EEG-NF induced FAA, analyses were performed offline. Data were downsampled and filtered, and then artifacts were rejecting by removing bad channels and running individual component analyses (ICAs) from which components associated with artifact were removed from the data. Discrete Fourier transform analyses were performed to extract alpha power (8-12 Hz) in the EEG of the F3 and F4 electrodes. FAA was assessed as a contract using the formula: FAA = ((p(F3)-p(F4))/P(F3)+p(F4)). A one-sample t-test was conducted to compare the mean FAA value to our null hypothesis of zero. No significant difference was found (FAA mean = -0.35, SD = 0.70; t(11)= -1.6; p >0.05). This suggests that EEG-NF based on positive memory recall did not induce the expected asymmetry.
The lack of a reliable FAA, even at the group level, does not encourage us to use this specific EEG-NF methodology in future work. The lack of asymmetry could be a result of the small sample size (n = 12). However, considering the success of past work in producing FAA, a more likely explanation is that the positive memory task used was ineffective. We plan to continue investigating methods of neurofeedback (EEG real-time fMRI neurofeedback) to control brain state and ultimately evaluate if neurofeedback can reduce TMS-induced intra- and inter-individual variability. The Genetic Underpinnings of Pubertal Timing in 7q11.23 Copy-Number-Variation: Age at Menarche, Pituitary Volume, and the Relation of Predicted STAG3L2 Expression to Gray Matter Volume
A. E Gouvea, Shau-Ming Wei, Michael D. Gregory, Tiffany Nash, Katherine M. Cole, Madeline R. Hamborg, J. Shane Kippenhan, Philip D. Kohn, Daniel P. Eisenberg, Bhaskar Kolachana, Carolyn B. Mervis, Peter J. Schmidt, and Karen F. Berman
INTRODUCTION: Children with Williams Syndrome (WS), a neurodevelopmental disorder caused by hemideletion (i.e., one remaining copy) of ~25 genes at chromosomal locus 7q11.23, enter puberty early, whereas individuals with 7q11.23 duplication syndrome ([Dup7]; with three copies of these same genes) have delayed puberty. We hypothesized that differential gene dosages underlying these copy number variations (CNVs) impact age at menarche (AAM). A previous GWAS study (~370,000 women) identified 389 signals that contribute to AAM, including the "stromal antigen 3-like 2 gene" (STAG3L2; rs2267812, p=1.69e-17), which resides in the low-copy-repeat region flanking the WS 7q11.23 locus. Here, we (1) examined how 7q11.23 CNVs affect AAM and STAG3L2 expression; (2) looked for an association between 7q11.23 CNV and pituitary volume since pituitary morphology in children with early puberty differs from controls; and (3) tested for a relation between imputed cortical expression of STAG3L2 and brain architecture in healthy volunteer adult women (HV). METHODS: Study 1: 19 girls with 7q11.23 CNVs (10 WS, nine Dup7) and 42 typically-developing girls (TD) reported AAM. For the 42 TD girls, polygenic scores (PGSs) for AAM were calculated based on reported GWAS summary statistics and correlated with AAM. STAG3L2 transcription in lymphocytes was computed for 76 children (23 WS, 13 Dup7, 40 TD) with RNASeq, and was tested for stepwise between-group differences with regression. Study 2: Investigators blinded to diagnostic group determined pituitary volume of 100 individuals (32 WS, 17 Dup7, 51 TD) by manual segmentation on T1-weighted 3T ME-MPRAGE scans. Group difference in pituitary volumes across 7q11.23 CNVs was assessed with linear regression. Study 3: In 145 HV, genetic data and structural MRIs were collected, and PGSs predicting cortical-expression of STAG3L2 were estimated using GTEx postmortem cis-eQTL data as weights for each SNP and then correlated with gray-matter volume (GMV) for each voxel (p<0.005). RESULTS: Study 1: AAM differed across CNV groups: greater gene dosage was associated with older AAM (WS=10.8+10yrs; TD=12.6+1.2yrs; Dup7=15.8+2.7yrs, p=6.15e-3). Further, PGS for AAM tended to correlate with AAM in TDs (p=0.06), and RNASeq data showed that STAG3L2 expression decreased with increasing CNV (WS>TD>Dup7, p=0.036). Study 2: Pituitary size was associated with 7q11.23 CNV: individuals with WS had the smallest pituitaries, whereas individuals with Dup7 had the largest (p=0.002). Study 3: In HV, imputed cortical expression of STAG3L2 was associated with increased gray-matter-volume (GMV) in medial PFC and insula, but with decreased GMV in dorsolateral PFC and inferior parietal lobule. DISCUSSION: AAM, pituitary volume, and STAG3L2 expression are moderated by 7q11.23 CNVs. Contrary to the expectations with hemideletion, STAG3L2 expression was increased in WS, suggesting the presence of a regulatory element in the 7q11.23 region. The reported link between STAG3 loss-of-function mutations and delayed puberty is consistent with findings of early puberty in WS (increased STAG3L2 expression) and delayed puberty in Dup7 (decreased expression). Our findings indicate that pituitary size is also genetically mediated and may be associated with the effects of the 7q11.23 CNVs on pubertal timing. Finally, GTEx-estimated STAG3L2 brain-expression is associated with cortical architecture in regions important for neurodevelopment. Predicting changes in mood and anxiety during the COVID-19 pandemic in a transdiagnostic sample of youth
A. Jeong, S. P. Haller, C. Archer, A. Jaffe, A. Harrewijn, R. Naim, J. O. Linke, J. Stoddard, M. A. Brotman
Background: Few studies have employed prospective longitudinal designs that include clinical or neurocognitive assessments prior to the COVID-19 pandemic onset to examine how variability in profiles may influence stress response. Here, we leverage existing pre-pandemic clinical and imaging data to model change in anxiety and mood following the COVID-19 pandemic in a transdiagnostic pediatric sample. The aim of the current study was two-fold. First, we examine associations between pandemic-related stress and increases in dimensions of developmental affective psychopathology. Second, we investigate whether attention towards threat and associated whole brain activation patterns predict change in anxiety and/or COVID-19-related worries during the pandemic.
Methods: A transdiagnostic sample of 81 youth ages 8-18 (M = 13.84 years, SD = 2.65; 40.7% female), who were enriched for psychopathology (Attention Deficit/Hyperactivity Disorder, Disruptive Mood Dysregulation Disorder, Anxiety Disorders) and typically developing children completed longitudinal clinical follow-up during months 6-12 of the COVID-19 pandemic including measures of anxiety, irritability, depression and ADHD, as well as assessment of COVID-related worries and stress (i.e., change in employment, social support, access to resources). Forty-six youth also completed a threat processing fMRI task prior to the onset of COVID-19. Clinical outcomes were assessed using child- and parent-report forms of well validated questionnaires. Within two years pre-pandemic, neurobiological correlates of threat-related attentional processes were assessed using a dot-probe task. Paired t-tests assessed changes in clinical scores pre-mid pandemic, mediation models examined COVID-related stress and worries as mediators of change in symptoms. Whole-brain models examined relationships between pre-pandemic activation to neutral and angry faces and mid-pandemic anxiety as well as pandemic-related worries. Results were thresholded at voxelwise p=.005, whole-brain cluster-corrected to p<0.05 (k=51).
Results: Child-reported anxiety and depression, and parent-reported anxiety significantly increased during the pandemic (all ps<.05), while symptoms of irritability and ADHD remained stable. Change in parent-reported anxiety was partially mediated by COVID stress and worries (all ps<.05), while change in child reported anxiety and depression was partially mediated by COVID worries only (all ps<.05). Elevated activation to neutral faces in several clusters including the bilateral striatum, left insula, anterior cingulate cortex, right inferior and left middle frontal gyrus prior to the pandemic predicted increases in parent-reported anxiety during the pandemic (all F(1.95,81.86)>14.44, p<.001), but not change in child-rated anxiety or pandemic worries.
Discussion: The present work expands existing knowledge on the mediating role of psychological stress on symptoms of anxiety and depression in adolescence. It also provides preliminary evidence that enhanced brain activity in response to neutral (potentially also more ambiguous faces) may renders youth more susceptible to the effects of anxiety-related psychological stress. Persistent Brain Network Changes Following Unfairness Predict Irritability: Implications for Our Understanding of Youth Mental Health Disparities
B. Brown, Christian Botz-Zapp, Amanda Chue, Reut Naim, Katharina Kircanski, Melissa A. Brotman, Ellen Leibenluft, & Julia O. Linke. Emotion and Development Branch, National Institute of Mental Health, Bethesda, MD
Background: In youth, irritability is a common and impairing transdiagnostic symptom. Irritable youth are particularly susceptible to environmental conditions that can be overtly unfair and perpetuate unequal chances of goal attainment. Research relates youth irritability to difficulties in regulating frustration in reaction to these conditions. This ultimately impairs their relationship with family and peers and academic performance. A recent study highlights aberrant recovery of neural networks from frustration following rigged feedback as a mechanism and potential treatment target for irritability. Here, we aim to replicate this finding using a different task that induces frustration through extreme difficulty, representing a more subtle operationalization of unfairness.
Methods: Fifty youth participated in this study (mean age=14.5, 24 females, 62% White, 12% multiple racial backgrounds, 8% Black, 18% declined information). Forty-two participants were diagnosed with at least one mental disorders (Disruptive Mood Dysregulation Disorder: [DMDD] n=15; Attention-Deficit/Hyperactivity Disorder: n=21, Oppositional Defiant Disorder [ODD]: n=8, anxiety disorders: n=17). FMRI data were acquired before (pre-task resting-state), during, and after (post-task resting-state) a frustrating, modified stop-signal task to examine brain network reconfigurations in response to and during recovery from frustration. Specifically, we were interested in replicating two prior findings: (1) the emergence of the fronto-temporal-limbic (FTL) subnetwork following frustration, and (2) the prediction of individual differences in irritability from FTL network efficiency, a graph-theoretical measure for parallel information processing, using a train/test/held-out procedure.
Results: During the task, we observed a significant increase in frustration ratings (F(1,49)=3.89, p=.001, n2=.460). Consistent with our hypotheses, the FTL emerged during post-task rest. Remarkably, all brain regions constituting the FTL in this study were part of the FTL in the prior report. In our train/test sub-sample (n=38), we could predict parent-rated irritability from the global efficiency of the post-task FTL (ß=-.47) and the global efficiency of an anterior default mode-temporal-limbic network that contains all FTL nodes during pre-task resting state (ß=.31) and in response to frustration during the task (ß=-.45), as well as diagnosis of DMDD (ß=.41) or ODD (ß=.39). Notably, this regression model allowed us to predict irritability in the previously unseen held-out subset (r=.63, p=.027, r^2=.40, RMSE=0.91).
Conclusions: We show that frustration induced through implicitly unfair conditions (i.e, task difficulty as opposed to rigged feedback) evokes changes in brain network configuration, including the emergence of an FTL subnetwork that persists after the task suggesting aberrant recovery from frustration as a mechanism of irritability. These changes are clinically meaningful as they allow us to predict individual differences in irritability, a common reason why youth are referred to clinical care. Future studies should investigate the recovery of brain networks following frustration as a function of the exposure to unfairness. Such future work could test the hypothesis that, particularly in marginalized youth, exposure to unfair environments might lead to increased irritability, a key symptom of depression and predictor of suicidality, thereby advancing our understanding of youth's mental health disparities.
Dynamic visual feature binding of face and body when perceiving emotional expression
M. Sargeant, Kunjan Rana, Jessica Taubert, Leslie Ungerleider & Elisha Merriam
While both face and body expression are involved in the perception of emotion, their interaction is not fully understood. We investigated how face and body expression are integrated to influence emotional judgments. How do face and body expressions interact to influence the perception of emotion? What is the temporal evolution of this integration? To answer these questions, we conducted a behavioral experiment in which participants evaluated the emotional expression of images created by joining faces and bodies. Face and body images were either emotionally congruent, with matching expressions (e.g., fearful body, fearful face), or emotionally incongruent, with unmatched expressions (e.g., fearful body, angry face). Each trial began when participants placed their mouse cursor at a fixed point at the bottom of the screen. The face and body composite image was then presented at fixation. Participants indicated their emotion expression judgment for that face/body combination by moving the mouse to one of the two targets. The trajectory of the mouse was recorded and used to infer the expression judgment over the course of the trial. Our results show that there is a preference for facial expression when identifying emotion on incongruent trials, consistent with previous findings (Solanas et al., 2018; Van de Riet & de Gelder, 2008). Moreover, the deflection of the mouse trace relative to a straight-line trajectory revealed biases in early weighting for both faces and bodies that differed from the eventual judgment on that trial. Our results reveal the utility of using dynamic mouse position for inferring emotional judgments and demonstrate that face and body expressions are dynamically weighted when participants evaluate emotional expressions. Differential effects of hippocampal, rhinal and orbitofrontal lesions on recognition memory in rhesus monkeys
B. Hines, G.P. FOMANI, A. LUZ-RICCA, M.C. SMITH, M.A.G. ELDRIDGE
There is evidence suggesting that the orbitofrontal cortex, hippocampus, and rhinal (perihinal + entorhinal) cortex may contribute to the recognition of visual stimuli. Pharmacological, cooling and ablation studies have established a critical role for perirhinal cortex in recognition memory tasks. Neurophysiological recordings have found neural correlates for recency and familiarity memory within perirhinal cortex, entorhinal cortex, and orbitofrontal cortex. There is disagreement in the literature about the role of the hippocampus in recognition memory.
We tested five rhinal-lesioned monkeys (perirhinal + entorhinal), two hippocampal-lesioned monkeys, four monkeys with rhinal-orbitofrontal cortex cross-lesions, and three controls on a serial recognition task that did not require simultaneous comparisons between stimuli. In each trial the monkey had to indicate whether the stimulus displayed was presented for a first or second time within the session by releasing a lever in one of two intervals: either immediately after the stimulus appeared (first interval) or later when a small central target changed from red to green (second interval). Stimuli were repeated once within the session, with the interval being 0-128 stimuli. The stimulus set consisted of 6000 images of animals in natural scenes. No stimulus was reused within a 30-day period.
Performance was analyzed using signal detection theory. Control monkeys reliably differentiated between the first and second presentations of a stimulus at all but the longest intervals, 64 and 128 intervening stimuli. HPC-lesioned monkeys performed at the level of controls across all intervals. The performance of the bilateral rhinal lesioned monkeys and that of the Rh-OFC cross-lesioned monkeys was impaired relative to controls at the group level. However, performance was highly variable within the latter two groups; at least one monkey from each condition performed as well as the control group.
We conclude that the hippocampus is not required for recognition memory in the format tested here and discuss variations in lesion extent that might explain the variability observed in the bilateral rhinal and rhinal x OFC cross-lesioned groups.
Expression of a virally-transduced estrogen receptor- fragment fusion protein in rhesus monkey brain using [18F]FES as a PET reporter probe
P. Wadhwa, P. Z. Fregonara, J.S. Liow, M.A.G. Eldridge, B. Li, X. Yan, W. Lerchner, M. Michaelides, S.S. Zoghbi, B.J. Richmond, R.B. Innis
Introduction: Positron emission tomography (PET) reporter gene systems have contributed to progress in cell/gene therapy, and have improved our understanding of the molecular pathology of neurological diseases by providing an in vivo molecular imaging tool. PET reporter genes can be incorporated into systems that are constitutively active (always 'on') or inducible (switched 'on' or 'off') and comprise of: (1) a PET reporter gene which is linked to a therapeutic gene of interest, packaged within a viral vector that can transduce the targeted neural cell population and (2) a complementary PET reporter probe that can image the expression of the reporter proteins within the transduced cells. This PET study is designed to assess whether [18F]FES can be used as a PET reporter probe to image an estrogen receptor-alpha (ER-a) fragment expressed from a fusion construct comprising Channelrhodospin2 and the ER-a ligand binding domain (ChRERa) in the rhesus monkey brain.
Methods: Lentivirus expressing ChRERa under the control of a human synapsin promoter (Lenti-ChRERa) and Adeno-associated virus expressing ChRERa under the control of a human synapsin promoter (AAV-ChRERa) were injected intracerebrally within the right and left anterior caudate, respectively, of two rhesus monkeys. [18F]FES baseline and blocked PET scans were performed before the viral transduction and baseline PET scan was performed after the viral transduction in both rhesus monkeys, with measurement of the arterial input function. Specific binding was measured as the difference between the baseline scan and that blocked by estradiol (0.1 mg/kg). Volume of distribution (Vt) was calculated using Logan graphical analysis with full arterial blood input function.
Results: Prior to viral transduction, [18F]FES uptake in the brain was similar between baseline and estradiol-blocked scans, showing that ER are not significantly expressed in the normal brain. High (and blockable) uptake was seen only in the hypophysis (a region known to have high ER density). Viral transduction induced a focal tracer uptake at the Lenti-ChRERa injection site in both rhesus monkeys (with an estimated increase of 70% in plasma-free fraction corrected Vt as compared to the baseline), but not at the AAV-ChRERa injection site.
Conclusions: The rhesus monkey brain has no significant baseline expression of ER, thus [18F]FES is a promising tracer to be used as a PET reporter probe. Intracerebral injection of Lenti-ChRERa successfully induced a detectable focal uptake of [18F]FES. Alpha 2-adrenergic mechanism in stress induced decision-making
C. Turner, Vladimir Visockis, Yogita Chudasama
The a2A-adrenergic receptor is closely associated with stress. In fact, systemic administration of yohimbine, an a2A receptor antagonist increases stress in rats and humans as measured through autonomic physiological responses (Johnston and File, 1989. Pharmacol Biochem. Behav. 32:151-156). In rats, it also leads to impulsive decision-making (e.g., Sun et al. 2010, Biol. Psychiat. 67:649-656). Moreover, the stress response is associated with significant increases in noradrenaline (NA) in the hippocampus (Tanaka et al. 1982. Pharmacol. Biochem. Behav. 16:315-319), and dopamine (DA) in the prefrontal cortex (Thierry et al. 1976. Nature. 263:242-244), which might stimulate the cortex to drive risky behaviors contributing to pathological tendencies towards gambling, substance abuse, and other high-risk behaviors. Here, we explored this possibility by combining a pharmacological stressor, FG7142 with adrenergic agonists and antagonists. We first trained rats on an operant touchscreen decision-making task in which rats chose between two visual stimuli. Responses to the 'safe' stimulus always resulted in the delivery of a certain reward (50 microliters sucrose). Responses to the 'risky' stimulus resulted in the delivery of an uncertain reward (10 microliters 75% of the time, and 170 microliters 25% of the time). The left and right positions of the visual stimuli were determined pseudorandomly. When given a systemic 4 mg dose of FG7142, the rats shifted their baseline strategies by increasing their choice of the safe stimulus and hence the certain reward. In addition, these animals showed long response latencies indicating a slow or deliberated response. In contrast, the co-administration of FG7142 and yohimbine made the rats riskier since these animals not only preferred the option that delivered the uncertain reward but also increased the speed of responding. In comparison, the combination of FG7142 and guanfacine, an a2A receptor agonist, had little impact on the animals' behavior. These data indicate that stress together with acute activation of the noradrenergic system may worsen or trigger risky behaviors observed in both clinical and non-clinical populations. Further studies will examine the combined effects of stress and dopamine stimulation on risky decision-making. Interactions between amygdala and cortex during face presentation at fixation and in the periphery
K. Rana, M. SARGEANT, J. TAUBERT, L. G. UNGERLEIDER, E. P. MERRIAM
Face processing is considered a function relegated to central vision. Supporting this notion are the behavioral observations that human participants tend to fixate on faces. On the other hand, it has also been shown that emotional faces are easily detected in the periphery, and the amygdala is engaged during the presentation of these peripheral faces. These findings suggest that some information about faces can be extracted from the periphery. Our goal was to investigate the functional communication between the amygdala and cortex while manipulating the screen location of faces, relative to fixation. To accomplish this, we measured brain activity using magnetoencephalography scanning during a task in which three images (size: 6 degrees across) were simultaneously presented to the observer, one image at fixation, flanked by two images 8 deg to the left and to the right of fixation. The images could either be a triplet of an object, face, and scene, or one of the aforementioned categories along with two noise images. The noise images were generated by phase-scrambling the images from the other categories. Decoding spectrotemporal activity revealed a bias for centrally-presented stimuli in the temporal lobes, which is consistent with the known central bias of the ventral visual pathway. In the amygdala, however, it was possible to decode between all stimulus locations with theta-band activity, supporting findings that it can discriminate peripherally presented faces. We used the weighted phase lag index measure to track the functional communication in the theta band between the amygdala and the cortex. We found significant theta-band connectivity between the amygdala and prefrontal cortex from 400 ms to 900 ms after stimulus onset. Our results show a delayed engagement between amygdala and prefrontal cortex in the theta band. This suggests a role of amygdala-prefrontal cortex communication in the conscious awareness of visual stimuli with greater socio-emotional meaning. The moderating role of ADHD symptoms on deficits in proactive control in youth with irritability
S. Shaughnessy, Jessica Bezek, Daniel S. Pine, Melissa A. Brotman, Ellen Leibenluft, Katharina Kircanski, Elise M. Cardinale
Irritability, or increased proneness to anger relative to peers, is highly associated with functional impairment in youth and commonly comorbid with Attention Deficit/Hyperactivity Disorder (ADHD) symptoms. Cognitive control, the ability to modulate attention in the pursuit of goal-directed behavior, is broadly implicated in the development of pediatric psychopathology. While much is known regarding the cognitive control deficits underlying ADHD symptoms, the role of cognitive control deficits in irritability, both with and without comorbid ADHD, remains unknown. No studies have dissociated associations between irritability and proactive (e.g. preparatory) versus reactive (e.g. stimulus-driven) control strategies. The current study presents novel work addressing this question. We examined the independent and interactive effects of irritability and ADHD symptoms on proactive and reactive control across a transdiagnostic sample of youth with varying levels of clinical irritability (Disruptive Mood Dysregulation Disorder [including individuals with sub-threshold symptoms] = 21, ADHD = 17, Healthy Controls = 38). 76 youth ages 8 to 18 ( M= 13.47, SD= 2.54; 50% female) completed the AX-Continuous Performance Task (AX-CPT), a well-validated paradigm for the evaluation of proactive versus reactive control strategies. In AX-CPT participants are instructed to identify a special ("A-X") letter pair. Responses to the A-X letter pairing occur frequently and thus can be compared to responses to other trial types (i.e., trials where the letter A is not followed by a letter X) to assess the degree to which the A-cue influences a participant to proactively plan for the subsequent letter. The tendency to rely on proactive, rather than reactive, control strategies was measured using two measures from signal detection theory: d' prime and A-cue bias. Higher d' prime and A-cue bias scores indicates a more planful strategy or greater reliance on proactive control. Irritability symptoms were measured with the parent-report Affective Reactivity Index (ARI) and ADHD symptoms were measured with the parent-report Conners Comprehensive Behavior Ratings Scale (CBRS). We conducted two independent multiple regression analyses predicting d' prime and A-Cue bias from irritability symptoms, ADHD symptoms, and the interaction between the two. All models included age as a covariate. Results revealed a significant interaction between irritability and ADHD symptoms on both d' prime (b = -0.21, SE = 0.08, t = -2.72, p = 0.008) and A-cue bias (b =-0.04, SE = 0.02, t = -2.35, p = 0.023); higher levels of irritability symptoms were associated with less proactive control, but only at high levels of ADHD symptoms (d' prime CBRS Scores > 37.79; A-cue CBRS Scores > 39.73). These findings present preliminary support that deficits in proactive control are associated with pediatric irritability in the context of high levels of comorbid ADHD symptoms. This may be particularly relevant for mechanistic treatment development for severe irritability and comorbid ADHD, as proactive control deficits may be a target for future therapeutic interventions. Pilot Study of a Future Thinking Task in Patients with Suicidal Ideation or a Suicide Attempt History
D. Campbell, Elizabeth Ballard, Jessica Gilbert, Carlos Zarate Jr.
Background: Previous research suggests that hopelessness may be a better predictor of suicidal behavior than depression itself (Beck et al., 1973). Hopelessness can be comprised of multiple constructs including a lack of positive thinking about the future and increased negative thinking about the future, both of which can be measured by a Future Thinking Task (FTT) (Macleod et al., 1993). During the FTT, participants are asked to think about events that may occur in the future over two time periods: the following week and the following 5-10 years. Studies have shown that suicidal patients show reduced positive future thinking when compared to healthy controls, while showing no difference in negative future thinking. (Macleod et al., 1998; Macleod et al., 2010). Alternatively, a recent study showed that both the absence of positive future thinking and the presence of negative future thinking predict later suicidal ideation better than hopelessness alone, but that the absence of positive future thinking is a stronger predictor (Rosario-Williams et al., 2021). It is important to replicate these findings across patients with varying levels of suicide risk and to examine if there are neural correlates of future thinking associated with risk for suicide. The current poster outlines a study design to conduct Macleod's future thinking task in our patient population and add an imaging portion to this task to measure neural correlates.
Methods: Patients and healthy volunteers across a continuum of suicide risk completed the FTT as part of their participation in the Neurobiology of Suicide Protocol (15-M-0188) at the NIMH. Participants were given a minute for each time period to list possible positive or negative events, resulting in four total categories (1wk-pos, 1wk-neg, yr-pos, yr-neg). After this task, participants rated each event's duration, similarity to events they've experienced in the past, vividness when imagined in their mind, likelihood, and emotional valence on a scale from 1-5. In the future, we will select three events from each of the four categories (twelve events total) to utilize in the magnetoencephalography (MEG) neuroimaging portion of this task. MEG data will be collected using a 275-channel CTF Omega system, and participants will be cued on the specific events that they listed during the behavioral task. Participants will be asked to imagine each event for two minutes, so the imaging task will take approximately 30 minutes.
Results: From a pilot of 4 individuals, participants were able to list between three and six possible events for each category (1wk-pos, 1wk-neg, yr-pos, yr-neg). Participants had no trouble completing the ratings for each event. On average, participants rated positive events as more vivid than negative events. Participants also rated negative events as lasting longer in duration on average than positive events.
Conclusions: This is a feasible and promising area of study to examine the use of future thinking as a predictor of suicidal behavior and to image biomarkers of suicide risk. Future directions include continuing the behavioral pilot and starting the imaging task in a sample of participants at risk for suicide. The effects of ketamine on arousal during resting state and task fMRI
V. Kotoula
Changes in vigilance and arousal can interfere with the study of intrinsic and task-evoked characteristics of brain function (Falahpour et al., 2018). These changes are particularly prevalent during the passive and uncontrolled resting-state, resulting in fMRI signal variability (Chang et al., 2016). In the present study, we examine the effects of ketamine on arousal during resting state and two fMRI tasks. We hypothesize that ketamine, compared to placebo would alter the arousal levels of depressed volunteers and that this would correlate with resting state activation and task fMRI performance. Arousal was assessed in 35 healthy controls and 24 depressed patients who took part in a double-blind, placebo-controlled study. Participants were scanned at baseline and 14 days after the ketamine and placebo infusions. Spatial correlations between the arousal template (Chang et al., 2016) and the fMRI signal were calculated at each time point in order to produce an arousal timeseries, for each subject and for each scanning session. These timeseries were compared between the two groups and drug conditions. Arousal did not differ at baseline between the healthy controls and depressed patients. Additionally, 14 days after its administration ketamine did not produce any significant changes in arousal. These results indicate that ketamine, when fully metabolized, does not significantly influence arousal levels during fMRI. Further investigation is however, needed in order to assess whether arousal levels would correlate with task performance in the two groups and whether ketamine, would influence arousal at different timepoints after its administration.
Spatial encoding of mPFC neurons
X. Ma, Z. Li
The ability to acquire and process information about the surroundings is crucial for animals to survive. The neural mechanisms underlying spatial encoding have been studied extensively. Much of this work has focused on the role of the hippocampus in representing spatial location during navigation behavior. Recently, evidence have emphasized a role for other neural structures, such as the prefrontal cortex (PFC), during spatial related behaviors. However, the properties of spatial encoding by mPFC neurons are largely unclear. In this project, we tackled this question by addressing what specific spatial information is encoded by mPFC neurons, and if spatial information is encoded by individual or populations of mPFC neurons. We trained mice to perform a T-maze delayed non-match-to-place (DNMTP) task and recorded single units in the mPFC during the task. We constructed a firing rate map along the mouse's trajectory in the maze and calculated spatial information content per spike (SIC) for each mPFC neuron. The firing rate map shows that some mPFC neurons fire at selective locations in the maze. SIC is higher when animals are running towards the reward port than when animals are running back to the task starting point after receiving rewards. In addition, we were able to use the firing patterns of recorded mPFC neurons to decode the mouse's spatial location, with the highest precision for running towards rewards than for running after receiving rewards. These results suggest that the animal's spatial location is represented by mPFC neuron firing patterns at both individual and population levels. Neural firing in the DNMTP task is potentially affected by working memory and reward other than spatial location. To tease out the potential effects of working memory and reward on spatial encoding of mPFC neurons, we recorded from the same mice during a passive alternation (PA) task, which is rewarded but not dependent on working memory and during free running in the T-maze without being rewarded or engaging working memory. mPFC neurons carried less SIC in the PA task than in the DNMTP task, and less SIC during free running than in PA task. Moreover, the decoding error of the animal spatial location was larger in the PA task than in the DNMTP task, and larger in the free running than in the PA task. These findings indicate that both working memory and reward enhance the spatial encoding of mPFC neurons. In summary, mPFC neurons encode spatial location at both individual and population levels. This spatial encoding is dependent on behavior state, and it is enhanced by engagement of working memory and reward seeking. Valence processing in the mouse auditory cortex
J. Johnson, Z, Li
The auditory cortex is the primary site of sound processing within the brain, however the processing of non-auditory information within this region is being increasingly discovered. Learning to associate stimuli emotional or motivational valence is a critical skill in survival, and disturbances in these associations are found in a range of diseases such as PTSD or schizophrenia. While alterations to tone frequency processing have been seen to be affected by associations with rewarding or aversive stimuli, it is unclear how these factors intersect at the neuronal level, and whether neurons within the auditory cortex have innate, conditional or long-term valence responsiveness independent of sound. Longitudinal two-photon calcium imaging was used to assay neurons in the auditory cortex during the conditioning, recall and pair switching of pure tones with both rewarding and aversive stimuli. Following conditioning, a subset of neurons in the auditory cortex were shown to respond to valence coded stimuli when either rewarding or aversive stimuli were presented alone, these neurons were composed of cells with and without tone responses. These valence responsive cells were predominantly active when either rewarding or aversive stimuli were presented but could also show responses to both valences. Once the initial conditioning pairs were reversed, subsets of neurons could undergo a switching of their stimuli response to the opposing valence, as well as gaining a new or losing the initial conditioned response. The valence responsive cells appear to form ensembles with tone responsive cells and potentially indicate a local mechanism to influence emotionally linked auditory information within the auditory cortex. A functional network perspective of fear extinction recall in anxiety disorders
I. Spaulding, Andrea L. Gold, Daniel S. Pine, Rany Abend
Background: Extinction recall (ER), or one's ability to recall extinction memory of a previously conditioned and extinguished threat, is hypothesized to constitute a key pathological mechanism in anxiety disorders as well as a target mechanism in exposure treatment. Greater understanding of the neural pathways that underlie ER could improve diagnosis and treatment outcomes. Furthermore, the conserved nature of ER circuitry offers opportunities for integrating insight from animal work on ER and clinical research on anxiety. Prior work from our group (Gold et al., 2020, American Journal of Psychiatry) has begun to examine anxiety-related perturbations in this circuitry related specifically to amygdala function but has not investigated potential differences in connectivity between other relevant regions. The current study extends this work by using a network approach to examine links between functional ER circuitry, as derived from animal work, and anxiety symptoms in anxious youth and adults.
Methods: 200 youths and adults (range: 8-50 years; 118 females) underwent a threat conditioning and extinction paradigm. Of those, 92 met criteria for anxiety disorders; 108 had no psychiatric diagnoses. Approximately three weeks later, they completed an fMRI scan on ER of the previously conditioned and extinguished threat, where they viewed morphed facial stimuli that varied in likeness to the actual threat. Functional connectivity data were preprocessed to correct for motion, coregistered to structural images, normalized to common space, smoothed, and denoised to account for confounding effects in BOLD signal. We conducted Generalized Psycho-Physiological Interaction models using our own atlas of regions encompassing the fear network to assess region-to-region connectivity. Second-level, network-based analyses tested whether connectivity in this circuitry during extinguished threat and safety covaried with anxiety levels (State-Trait Anxiety Inventory), age, and sex.
Results: Networks emerged linking anxiety and functional connectivity during processing of safety cues (F(4, 195)=4.37, pFDR=0.02). Within one network, amygdala-dorsolateral prefrontal cortex connectivity negatively correlated with levels of anxiety, while midline thalamus-dorsomedial prefrontal cortex connectivity positively correlated with levels of anxiety. In response to ambiguous threat cues (50% safety cue, 50% threat cue morph), we found significant networks linking levels of reported anxiety and functional connectivity (F (4, 195)=4.48, pFDR=0.02). Hypothalamus-amygdala connectivity positively correlated with levels of anxiety, while thalamus-bed nucleus of the stria terminalis connectivity negatively correlated with levels of anxiety. All findings remained significant after controlling for age and sex. There were no significant associations between anxiety and functional connectivity to the extinguished threat cue.
Conclusion: Alterations in connectivity in fear-related networks during ER in individuals with higher levels of anxiety may suggest an impairment in successful fear regulation to ambiguous cues, and perhaps even in the ability to identify safety cues. Future analyses will incorporate physiological response data from the threat conditioning task as a covariate in connectivity analyses to consider how initial threat responses may later impact ER. In addition, future work will examine ER as a potential biomarker for response to treatment in youth with anxiety, where participants complete ER before and after cognitive behavioral therapy. Investigating the mental representation of observed grasp movements through similarity judgements
L. Ettensohn, K. Woodard, L. G. Ungerleider, C. I. Baker, M. Vaziri Pashkam
Hand grasp movements constitute a large portion of human's everyday activities. In addition to preforming hand grasp movements ourselves, we regularly observe others grasping objects and can judge these grasps by their similarity. What are the core features relevant for similarity judgements of observed grasp movements? Do people's similarity judgements of grasp movements match objective grasp similarities based on kinematics of the movement? To answer these questions, we first conducted a hand grasp movement experiment. We placed 16 sensors on each participants' (n=14, 8=female) hand and measured their movements in the 3 dimensions as they grasped a set of 58 naturalistic 3D printed objects (e.g. spoon, teapot, teddy bear). Using these kinematic data, we calculated the similarity between grasp movements and constructed a similarity matrix based on objective measurements. Next, we used the kinematic data to create point-light videos to serve as stimuli in our second experiment. Our second experiment was an odd-one-out similarity judgement task. Participants on Amazon Mechanical Turk (n=350) identified the most distinct grasp among triplets of the grasp videos (130 data points were collected for each pair). These judgements were used to construct a subjective similarity matrix. Both the objective and subjective similarity matrices had high reliabilities (r2 > 0.7). Surprisingly, the correlation of these two matrices was ~0.37: significantly above zero (p < 0.001) but also significantly below the noise ceiling (p < 0.001). These results demonstrate that humans rely on systematic features when judging the similarity grasp movements, but these subjective judgements do not mirror the objective similarity of grasp kinematics. These results suggest that distinct neural representations may support action observation and action execution. Lateral intraparietal sulcus power and rates of temporal discounting are related in the alpha, beta, and gamma frequencies in patients with suicidal history.
G. Anderson, Dede K. Greenstein, Courtney R. Burton, Jessica R. Gilbert, Elizabeth D. Ballard, Carlos A. Zarate Jr.
Background: Impulsivity, reward processing, and psychopathology can be understood using temporal discounting, a neuroeconomics metric that quantifies the decline in the current value of a reward in relation to the delay of its receipt. Patients experiencing suicidal ideation (SI) have been shown to value a lower current reward over a higher delayed reward (i.e., increased temporal discounting), compared to healthy control participants (HCs). Additionally, previous studies have demonstrated that activity within the lateral intraparietal sulcus (LIP) is associated with individual-specific rates of temporal discounting, while activity within the anterior insula is associated with SI. We hypothesized that temporal discounting rate would be associated with LIP activity for all participants and that anterior insula activity would be reduced in patients with SI history versus HCs. We also hypothesized that higher discounting rates would correspond to higher levels of depression, anhedonia, and impulsivity.
Methods: In this ongoing study, we examined electrophysiological correlates of temporal discounting in patients with a recent suicide attempt (i.e., within two weeks; AS, n=8), patients with a history of suicide attempt but no attempt or ideation within the last year (HS, n=20), and HCs (n=19). Prior to scanning, participants completed the 27-item Monetary Choice Questionnaire (MCQ), Montgomery-Asberg Depression Rating Scale (MADRS), Snaith-Hamilton Pleasure Scale (SHAPS), and Barratt Impulsiveness Scale (BIS). An overall k value was calculated from the MCQ, with higher k values indicating higher discounting rates. Up to one week later, eight minutes of eyes-closed, resting state magnetoencephalography (MEG) was collected. Synthetic aperture magnetometry was used to project power in five canonical frequency bands - theta (4-8 Hz), alpha (9-14 Hz), beta (15-29 Hz), gamma (30-58 Hz), and high gamma (62-118 Hz) - using a realistic head model on a 5-mm grid over the entire rest period. Analysis of variance was used to evaluate group (AS, HS, HC) and discounting rate (k) effects within each frequency band. Pearson correlational analyses were used to assess the relationships between k and MADRS, SHAPS, and BIS total scores.
Results: There were no effects of group on power across frequencies. However, there was an effect of discounting rate, such that participants demonstrating a higher k value showed reduced alpha, beta, and gamma power in LIP (p=.15; p=.20; p=.20); reduced alpha and beta power in frontal regions (p=.20; p=.15); and reduced high gamma power in visual-processing regions of the occipital and temporal lobes (p=.20; p =.20). K and BIS scores were positively related (R=.199, p=.04). While k was not related to MADRS or SHAPS scores, SHAPS was related to MADRS and BIS (r=.741, p=.00; r=.285, p=.004).
Conclusions: MEG findings align with, and expand on, previous studies, implicating intraparietal regions in temporal discounting for both patients with SI history and HCs. Results from clinical measures support previous findings that k can be used as a behavioral measure of impulsivity. Future work will explore the temporal dynamics of frequency-specific changes in LIP and group differences in clinical outcomes. Analysis of Ligand-receptor Communication in single nucleus RNA-seq of the Cerebral Cortex
D. Kim, Pavan Auluck, Stefano Marenco
Single nucleus RNA-sequencing (snRNAseq) data have elucidated cellular heterogeneity in human brain tissue, including the cerebral cortex; however, our understanding of how cell types communicate with each other is still limited. It may be possible to discover cell-to-cell communication (CCC) using ligand and receptor gene expression data from snRNAseq using CellChat, a recently developed program that utilizes network centrality and pattern recognition to extract intercellular communication for single cell RNA-sequencing data. In this study, we modify CellChat to investigate synaptic CCC in postmortem dorso-lateral prefrontal cortex (DLPFC) and subgenual anterior cingulate (sgACC). snRNAseq was performed on samples from the DLPFC and sgACC from eight non-psychiatric donors (age = 44.8 +/- 11.2 years) using the 10X Genomics platform. 47 cell subpopulations were detected: 20 excitatory, 22 inhibitory neuronal sub-clusters, astroglia, microglia, oligodendrocytes, oligodendrocyte precursor cells, and endothelial cell types. The new database curated in this study filtered the CellChat database to only include ligand and receptor genes that are found in the synapse according to Synaptic Gene Ontologies and Annotations Consortium (synGO). The database newly incorporates ligands and receptors involved with classic neurotransmitters (GABA, glutamate, dopamine, acetylcholine, serotonin, and norepinephrine) and accounts for multi-subunit receptor complexes as currently known in the literature. Among the 47 cell types, CellChat detected 112 significant ligand-receptor pairs, which were further categorized into 6 signaling pathways. Additionally, it identified incoming and outgoing communication patterns for each cell type. While most communications seemed to be non-specific, this study revealed a number of specific inputs to cell types of interest. For example, von Economo neurons (VEN) received specific GABA signaling through the GABRA6-GABRB3-GABRG2 receptor complex mostly from LAMP5 and PVALB inhibitory cell types. VEN also received specific signaling from layer VI excitatory neuronal cell types of the FEZF2 marker via the SEMA3 pathway. Curation of a robust ligand-receptor database and analysis of snRNAseq data using such programs as CellChat may provide insight on connectivity between brain cell subpopulations. With a more comprehensive understanding of ligand-receptor interactions in the human brain, we may be able to characterize differences in CCC between cortical regions or between clinical groups. Modeling behavioral avoidance in anxious youths using a novel conflict paradigm
P. Newsome, Sonia G. Ruiz, Daniel S. Pine, Rany Abend
Background: Approach-avoidance conflict (AAC)-the internal dissonance generated when a decision may elicit positive or negative consequences-is characterized by directly conflicting motivational systems (i.e., reward and punishment). Anxious individuals tend to resolve this conflict by sacrificing retrieval of a reward to avoid a threatening stimulus (i.e., passive avoidance). A majority of anxiety research has focused on either threat or reward responses independently, but less is known about the processes underlying conflict between these competing motivations, and their relation to anxiety. Importantly, most of the existing research examining passive avoidance utilizes non-human samples. Our study aims to quantify AAC as a function of potential reward and punishment magnitudes and identify anxiety differences in approach and avoid motivations and the resolution of the AAC.
Methods: We are currently piloting a novel computer-based approach-avoidance task to investigate AAC processing in healthy and anxious youths (N=11, Mage= 14.17 years, SDage= 2.81 years, 5 females). The task included varying magnitudes of reward and punishment which were accessed by opening a door. As each door was presented, participants' distance from the door was recorded to index avoidance behavior. We used a linear mixed-effects model to quantify the effect of approach and avoid motivations on avoidance. Additionally, we assessed split-half reliability of approach and avoid motivation indices.
Results: Analyses on preliminary data revealed that potential reward magnitude has a significant positive effect on approach behavior, t(1456)=7.20, p<0.001, and punishment magnitude has a significant negative effect on approach behavior (i.e., greater avoidance), t(1456)=-11.11, p<0.001, indicating task validity in assessing motivated behavior. Correlations of these indices between task runs were significant (rr=0.78, pr
=0.01, rp=0.72, pp=0.03, rrp=0.76, prp=0.02), indicating its reliability.
Discussion: Our findings support that approach, avoidance, and conflict resolution behaviors are motivated in part as a function of reward and punishment magnitudes. Preliminary results suggest that our new task can reliably and validly quantify these motivations. In future analyses, we will integrate skin conductance response (SCR) and eye tracking data to explore how AAC processing interacts with peripheral physiology and visuospatial attention bias in anxious and healthy youths. Ultimately, refining our understanding of the underlying features of dysfunctional AAC processing may aid the development of improved interventions for individuals with anxiety and other affective psychopathology. PKA Phosphorylation of Melanopsin Extends the Signaling Range of M1 ipRGCs
A. Nobleman, Randy A. Grant, R. Lane Brown, Phyllis R. Robinson, Samer Hattar
~~Melanopsin expressing retinal ganglion cells (RGCs) are intrinsically photosensitive and therefore are known as ipRGCs. Melanopsin and ipRGCs are major drivers of non-image forming visual behaviors such as circadian photoentrainment and the pupillary light reflex in mammals. ipRGCs as a population have recently been shown to signal over a wide range of light intensities from very dim to bright light. The majority of individual ipRGCs respond maximally to 480nm light of distinct intensities and then are silenced in a process known as depolarization block. Individual ipRGCs reaching block at distinct intensities allows the population as a whole to respond across such a wide range of light intensities. How individual ipRGCs within the population modulate their signaling to regulate depolarization block is of key importance to understanding how ipRGCs respond across changes in the light environment to regulate non-image forming behaviors. I hypothesize that PKA phosphorylation of melanopsin which has been shown to attenuate melanopsin signaling in vitro, is a mechanism that regulates depolarization block of ipRGCs at distinct light intensities. ipRGCs with greater PKA phosphorylation of melanopsin will show attenuated signaling but will reach depolarization block less quickly and thus be capable of responding to higher light intensities. To test this, I have examined the impact of a loss of PKA phosphorylation on melanopsin mediated behaviors including masking as well as assessing the physiological impact of dopamine-dependent activation of PKA on ipRGC signaling in vivo. Results suggest that a loss of PKA-dependent phosphorylation of melanopsin impairs masking behavior in mice exposed to bright light during the dark phase across multiple light intensities. Additionally single cell recordings demonstrate that dopamine produces an increase in cell spiking for a subset of ipRGCs. Taken together these results suggest PKA phosphorylation of melanopsin plays a role in regulating ipRGC signaling over a range of light intensities. Recurrence Quantification Analysis for the Differentiation of Actigraphy Patterns in Major Depressive Disorder in Response to Ketamine
C. Punturieri, J. W. Evans, C. A. Zarate Jr.
Irregularities in circadian rhythms have been widely reported in individuals with Major Depressive Disorder (MDD). Actigraphy metrics can be used to evaluate variations in 24-hour patterns of motor activity. Previous work has centered around nonparametric variables assuming constant periodicity. Recurrence Quantification Analysis (RQA) is a type of complexity analysis which quantifies recurring patterns in time series data. RQA differentiates between noise (i.e., sudden bursts of activity) and repeated patterns of activity (i.e., varying periodicity). Complexity analyses used in conjunction with existing measures may supplement our understanding of activity pattern differences in those with and without MDD. A more fine-grained grasp of changes in activity patterns over treatment course may be particularly beneficial in understanding the effects of rapid-acting antidepressants like ketamine, wherein response is quicker but less sustained than with traditional antidepressants. We compared several nonparametric and complexity measures of actigraphy data in the context of a clinical trial of ketamine.
Thirty-two depressed subjects ("MD"; 18 female, mean age: 36.5 years+-10.7) and 15 healthy controls ("HC"; 9 female, mean age: 36.6 years+-10.7) wore an Actiwatch (AW64; Philips, Amsterdam, the Netherlands) for 28 days during a randomized crossover study. Subjects received two infusions over a 40-minute period, two weeks apart, of either 0.5mg/kg intravenous infusion of ketamine or saline. Following masking, pyActigraphy (https://github.com/ghammad/pyActigraphy) was used to compute nonparametric variables. Recurrence plots, generated from RQA, were calculated using TOCSY (tocsy.pik-potsdam.de). Quantitative metrics describing the diagonal and vertical line structures of the plot, representing the stationarity and length of activity, were then evaluated. Linear mixed effects models were used to examine the relationship between actigraphy variables and fixed effects of age, sex, and the interaction of drug (saline or ketamine) by diagnosis (MDD or HC).
Twelve individuals (seven MDs, five HCs) were excluded due to cluttering in the recurrence plots or insufficient data quality. A final sample of 25 MDs and 10 HCs were included in the analysis. We found a slight effect of gender on laminarity (t(24)=-2.115,p=0.05), a measure of frequency of extended activity. In addition, we found effects of age and determinism (t(24)=-2.909,p=0.01), laminarity (t(24)=-2.417,p=0.02), vertical average (t(24)=-2.997,p=0.01), diagonal entropy (t(24)=-2.469,p=0.02) and vertical entropy (t (24)=-3.232,p=0.004). These findings suggest older subjects have less consistent (i.e., fewer repeated patterns of activity) and less persistent activity patterns (i.e., less frequent periods of extended activity). No other variables were associated with treatment response, diagnosis, or drug condition.
This preliminary work builds on a recent study which examined the ability of complexity and nonparametric variables to differentiate between depressed and non-depressed individuals. The observed relationship of several complexity variables and age highlights the ability of RQA to parse apart expected age-related trends. We did not find a relationship between diagnosis or treatment and any actigraphy variables, which may be due to dilution of the rapid effects of ketamine from averaging over the study duration. RQA of actigraphy data may ultimately help facilitate the non-invasive understanding of treatment response in depression. Dissociating irritability and rigidity in youth: A pilot study
L. Nguyen, Ellie Xu, Stephen J. Gotts, Katharina Kircanski, Philip Shaw, Melissa A. Brotman, Daniel S. Pine, Ellen Leibenluft, Julia O. Linke
Background. In youth, irritability, defined as increased proneness to anger, is an impairing yet common symptom that predicts suicidality and later life psychopathology. Irritability often co-occurs with cognitive rigidity, defined as the impaired ability to adapt attention and behavior to changing environmental demands. Exaggerated responses to frustration might be a shared mechanism between both symptoms. Here, we employ an experimental approach to investigate how irritability and rigidity are reflected in behavioral and neural responses to a frustration induction task and the recovery from frustration.
Methods. We obtained self and observer ratings of irritability (Affective Reactivity Index) and rigidity (Detail and Flexibility Questionnaire) from a preliminary sample of 20 youth (Mage=13, 50% Female, White=9, Latino/Hispanic=1, Black/African American=5, Multiple Races=4, Unknown=1) that met criteria for either attention-deficit/hyperactivity disorder (n=6), an anxiety disorder (n=3), disruptive mood dysregulation disorder (n=4), or participated as healthy volunteers (n=7). All participants underwent functional magnetic resonance imaging, which comprised a resting-state scan that served as baseline followed by a frustration-induction task and a second resting-state scan to capture recovery from frustration. As frustration elicits responses in distributed brain regions, we used a graph-theoretical approach and focused on changes in the functional segregation of brain networks from baseline to task and baseline to post-task rest. We focused on two key topological network metrics: (1) global efficiency, which indicates the brain's capacity for parallel information processing, and (2) mean local efficiency, which represents the average efficiency of information transfer between neighboring regions. In case of significant shifts between conditions in any of these metrics, we investigated whether the global efficiency of condition-specific networks was driving the effect.
Results. Irritability and rigidity were strongly correlated (rS~.58-.65, ps<.009). Irritability was positively associated with the task-induced increase in sadness (F(1,17)~6.3-8.3, ps<.022) and rigidity related positively to the task-induced increase in frustration (F(1,16)=4.47, df = 16, p=.050). Youth- (rS=-.25, p=.049) and parent-rated irritability (rS=-.37, p=.002) and parent-rated rigidity (rS=-.46, p=.043) were associated with changes in mean local efficiency, but not global efficiency of brain networks from pre- to post-task resting state, and not from pre-task rest to task. Secondary analyses showed that irritability and rigidity were associated with distinct post-task specific modules. Youth-rated irritability was associated with lower efficiency of the fronto-temporal-limbic module (rS=-.22; p=.043), parent-rated irritability related to higher efficiency of the ventral fronto-subcortical module (rS=.37; p=.003), and parent-rated rigidity related to higher efficiency of the fronto-parietal-salience module (rS=.39; p=.045).
Conclusion. Our findings suggest exaggerated emotional responses and perturbed recovery of neural networks following frustration as mechanisms of both irritability and rigidity while highlighting differential effects on mood (i.e., irritability: increase in sadness, rigidity: increase in frustration) and associations with distinct neural networks. Our results also link parent- and youth ratings to different neural networks underscoring the need for further analyses of informant discrepancies. Future studies in larger samples should replicate these results and further characterize the interactions between irritability and rigidity.
Parsing Inattention, Hyperactivity, and Irritability: A Comparison of two Latent Variable Models
B. Scheinberg, Ellie Xu, Shannon Shaughnessy, Katharina Kircanski, Melissa A. Brotman, Ellen Leibenluft, Julia O. Linke
Background. Irritability, defined as an increased proneness to anger, is highly prevalent in the context of attention-deficit/ hyperactivity disorder (ADHD) and has been proposed to represent a core feature or subtype of ADHD. However, dissociating irritability from core ADHD symptoms (i.e., inattention, hyperactivity) remains challenging. Here, we evaluate the utility of a bifactor approach to parse unique and shared variance between irritability, inattention, and hyperactivity.
Methods. We obtained parent-report Conners Comprehensive Behavior Ratings Scale (CBRS) for ADHD symptoms and the parent- and youth-report Affective Reactivity Index (ARI) for irritability symptoms from 525 youth (Mage= 12.5 years, 45% female; 12% Irritable [IRR; clinically impairing irritability as indexed by a diagnosis of disruptive mood dysregulation disorder [DMDD] or subthreshold DMDD symptoms], 32% clinically impairing irritability comorbid with ADHD [IRR+ADHD], 21% ADHD without clinical irritability, and 35% healthy volunteers [HV]). In MPlus, we first conducted an exploratory factor analysis on the CBRS that identified three latent factors, which broadly mapped onto the anticipated latent dimensions: inattentiveness, hyperactivity, and irritability. We then selected the top 6 items from each factor as input for a confirmatory factor analysis (CFA), which included the three specific latent factors and a bifactor analysis which comprised an additional shared factor. We compared fit indexes of the CFA and bifactor models and tested associations with the ARI and differences between diagnostic groups.
Results. Both the first- and second-order model fit the data well (CFA/bifactor: CFI= 0.994/0.994, RMSE=.073/.067, CI=.066-.080/.060-.074, all p<0.001). All three CFA-factors correlated with parent- (all p <.001) but not youth-report ARI (all p>.07). The bifactor irritability latent factor was associated with parent-(p <.001) and youth-report ARI (p=.01); the shared factor correlated with parent-report ARI (p<.001), but the inattention and hyperactivity factors were uncorrelated with the ARIs (all p>.10). The latent inattention (CFA: HV=IRR Discussion. Our findings suggest the utility of a bifactor approach in parsing the three highly comorbid symptom dimensions of inattention, irritability, and hyperactivity given the specificity of associations between latent factor scores from the bifactor model and additional irritability measures. Further, the bifactor solution emphasized the relevance of the shared factor over the hyperactivity-specific factor in discriminating between HV, clinically relevant irritability, and ADHD. Future studies investigating the validity of both models testing their value for the identification of neurobiological mechanisms, or the prediction of treatment response, are needed. Graded hippocampal activity during naturalistic recall is observable after multi-echo, but not single-echo, fMRI preprocessing A. Agron, Adrian W. Gilmore, Estefanía I. González-Araya, Stephen J. Gotts, & Alex Martin Recent years have seen a trend in cognitive neuroscience studies to shift towards more naturalistic, and less artificial, experimental paradigms. Our lab recently implemented an overt recall paradigm in an fMRI environment to understand real world autobiographical retrieval processes. In-scanner speech has historically been avoided due to data quality concerns that accompany head motion. The task involved 40 human participants overtly recalling recent and remote autobiographical events for periods of ~2 minutes and was intended to test competing theories of hippocampal involvement in remote recall. Data were processed using multi-echo ICA (ME-ICA), an advanced fMRI denoising technique. Benefits of acquiring multiple echoes include reducing thermal noise, identifying nuisance signal components, and improving the overall quality of BOLD data, which would make it intuitively sensible to pair with a study involving in-scanner speech. However, acquiring multiple echoes incurs a cost to the temporal and spatial resolution of the acquired BOLD data and increases the overall complexity of data analysis. Therefore, the goal of the current analysis was to determine if ME-ICA's theoretical benefits might lead to a practical difference in the overall results of the experiment by re-examining our multi-echo dataset (Gilmore et al., 2021) and comparing the results to a "traditional" single-echo analysis of the same data. Both processing streams utilized the same initial preprocessing steps (despiking, slice-time correction, and rigid-body motion correction) and both were rescaled, detrended, and analyzed using the same modeling parameters. Three results are notable. First, the overall signal quality was significantly improved following ME-ICA denoising. Second, as a result of this improved denoising, ME-ICA denoising revealed temporally graded activity in right lateral parietal and left frontal regions that was not detected by the single-echo analysis. Third, region of interest analyses focusing on hippocampal subregions produced qualitatively different results patterns between the two analysis approaches. Whereas no significant differences in hippocampal activity were observed as a function of event recency in the single-echo analysis, a temporally graded pattern (recent > remote) was observed in posterior hippocampal regions in the ME-ICA processed data. Compared to the ME-ICA data, single-echo results rarely differed from baseline activity in the hippocampus bilaterally, which would make it difficult in general to associate observed activity with the experimental manipulation. Thus, whereas the outcome of the single-echo analysis did not clearly support any specific model of hippocampal function, ME-ICA results supported predictions of the Standard Model of Consolidation and a time-limited hippocampal involvement (e.g., Zola-Morgan & Squire, 1990). The comparison demonstrated that ME-ICA proved critical to our analyses. These data provide a practical example of the benefits multi-echo acquisitions and ME-ICA might offer to naturalistic paradigms and emphasize that effects may emerge in ways that are subtle yet important for informing theoretical debate. Using Ecological Momentary Assessment to Examine Associations among Anxiety Symptoms, Irritability Symptoms, and Perception of Social Interactions with Peers during Adolescence M. Meyer, A. R. Smith, R. Naim, K. Kircanski, D. S. Pine, E. Leibenluft, M. A. Brotman, E. M. Cardinale Introduction: Adolescence is a sensitive period for refining social skills and developing peer relationships. Fostering adaptive social relationships during this period of life is associated with psychological well-being and positive socio-emotional development in adulthood. Unfortunately, anxiety and irritability commonly increase and co-occur during adolescence; psychopathological symptoms may impede the development of social skills necessary for adaptive peer relations. In line with this notion, both youth with clinical anxiety and youth with chronic irritability report problems with their peers (e.g., increased negative emotions; Smith, A.R., 2019). While social problems have been well-documented in youth with anxiety (e.g., cognitive biases, avoidance), little research exists examining social experiences of youth with irritability or co-occurring irritability and anxiety symptoms. We aim to explore associations between shared versus unique features of irritability and anxiety with adolescent’s perception of their interactions with peers, using Ecological Momentary Assessment (EMA). EMA enables researchers to assess participants’ moods and social experiences in real-time, providing greater context to self-reported experiences and in an ecologically-valid manner. Method: We sampled 245 youth (M age=12.70, SD=2.68, 51.4% female) with primary diagnoses of an anxiety disorder (n=115), attention deficit hyperactivity disorder (n=25), disruptive mood dysregulation disorder or subthreshold symptoms (n=46), and healthy volunteers (n=59). For seven consecutive days, three times each day (morning, afternoon, evening), participants responded to smartphone-administered EMA. Participants were asked to rate the quality of recent peer interactions on a 4-point Likert Scale (“very positive” to “very negative”), with the option to report “I haven’t had any interactions with other kids since the last beep.” Only participants who completed 1/3 of the prompts will be used in analyses. Anxiety and irritability symptoms were assessed through the parent- and self-report versions of the Screen for Child Anxiety Related Emotional Disorders (SCARED; Birmaher et al., 1997) and Affective Reactivity Index (ARI; Stringaris et al., 2012), respectively. The shared and unique variances of anxiety and irritability were estimated using a bifactor latent variable approach. Confirmatory factor analyses confirmed good fit (CFI=0.970, TLI=0.962, RMSEA=0.070, CI90=[0.061-0.079]) of an established model (Cardinale et al., 2019). Planned Analyses: To characterize associations among anxiety, irritability, and perception of peer interactions, we will run separate Multilevel Models (MLM) in R (lme). We will examine associations between shared and unique variances of anxiety and irritability as estimated by the bifactor model, with EMA measures of (1) time spent with peers and (2) quality of recent peer interactions (i.e., negative or positive). By understanding how psychopathological symptoms relate to perception of social experiences, we may be able to better inform prevention and intervention programs to help youth with impairing anxiety and irritability create and maintain adaptive social relationships. Neural Basis of Resting State Functional Connectivity S. Shahsavarani, David N Thibodeaux, Chinwendu J Nwokeabia, Weihao Xu, Fatema Lodgher, Daniel Handwerker, Javier Gonzalez-Castillo, Peter Bandettini, Elizabeth MC Hillman Introduction: The neurons in the brain are constantly interacting, even in the absence of any sensory input, behavioral output, or cognitive task. Studying the structure of this intrinsic activity and its effect on behavior and cognition has been the target of significant research efforts. Resting state dynamic functional connectivity (rs-dFC) analysis using functional magnetic resonance imaging (fMRI) data has been widely used to indirectly characterize the spatiotemporal properties of spontaneous activity by measuring blood oxygenation level dependent signals as a proxy for neural activity. Despite the prevalence of fMRI rs-dFC, there are non-trivial gaps in our understanding of how this measure relates to intrinsic neural activity. In this study, we aimed to address one of such gaps that is to characterize the neural correlates of fMRI rs-dFC. To do so, we investigated the brain-wide spontaneous time-varying functional connectivity (FC) patterns using both neural calcium and hemodynamic. Further we examined the relationship between spontaneous FC fluctuations and behavioral/physiological variables in awake, behaving mice. Method: Simultaneous neuronal and hemodynamic signals were recorded longitudinally in five thinned-skull adult Thy1- jRGECO1a mice using Wide Field Optical Mapping (WFOM). The mice were allowed to freely move on a rotating wheel while their heads were fixed. To measure changes in behavior and physiological arousal, variables such as locomotion, whisking, and pupil diameter were extracted from simultaneous video monitoring of the mouse. Applying pairwise Pearson's correlation on all temporal segments overlapping with each behavior of interest, we identified five distinct FC maps, both neural and hemodynamic, related to behavior and arousal including sustained locomotion, locomotion offset, high arousal right after locomotion offset, low arousal during sustained rest, and locomotion onset. Next, to predict the temporal evolution of behavioral states during the experimental sessions, we modeled every FC frame as a linear combination of these representative FC brain states using non-negative least squares. Results: Our results show that FC patterns, both neural and hemodynamic, can be robustly predicted. That is, the distribution of the state coefficients estimated by the model were in accordance with mice's behavior. Further, during 'rest' we observed systematic shifts between two FC brain states, again both neural and hemodynamic, which could be linked to changes in the mouse's arousal. Analysis of the cortical representation of the FC networks reveals that a key feature of shifts in arousal is a change in spontaneous activity of anterolateral brain regions that become significantly less synchronized with other brain regions during the low arousal state. Conclusion: Using both neural and hemodynamic data, these results provide strong evidence that patterns seen in fMRI rs-dFC have a neural basis, and fluctuations in neural FCs can be detected in hemodynamic data. This work adds to our understanding of how to interpret real-time spontaneous activity in the awake, behaving brain. Design and Synthesis of Radioligands for Selective Imaging and Quantification of Phosphodiesterase 4D in Brain with Positron Emission Tomography M. Jiang, S. Telu, V. W. Pike Phosphodiesterase-4 (PDE4) enzymes catalyze the hydrolysis of the second messenger, cAMP. Studies have suggested that PDE4 inhibition might have positive therapeutic effects in neuropsychiatric disorders. However, rolipram, an early PDE4 inhibitor, that entered evaluation for treatment of major depression was withdrawn as a candidate drug due to dose-limiting side-effects. Novel allosteric inhibitors with PDE4D subtype selectivity have since been developed and they have exhibited enhanced effects in memory and recognition with improved tolerability in mouse model studies.1 Through recognition of a single amino acid difference on a key regulatory domain UCR2, a PDE4D allosteric inhibitor binds with UCR2 and closes the PDE4D catalytic site for cAMP hydrolysis. One PDE4D inhibitor, BPN14770, has recently been evaluated for the treatment of Fragile X Syndrome in phase II clinical trials. Ability to image and quantify brain PDE4D with positron emission tomography (PET) would benefit further drug discovery and investigation of neuropsychiatric disorders. Our group has aimed to develop radioligands for PET imaging of brain PDE4D for these purposes. Our preceding work explored several chemical series and selected four leads with alkoxypyridinyl cores.2 Several ligands were successfully labeled with cyclotron-produced carbon-11 (t1/2 = 20. 4 min) and evaluated with PET in monkey. Two of the radioligands gave sizable PDE4D-specific PET signal in primate brain. However, accumulation of radiometabolites in brain was found in subsequent PET experiments in human rendering the radioligands unsuitable for quantifying PDE4D. Hence, we have pursued further structural modifications to retain high affinity and selectivity to PDE4D, while also reducing the possibilities for problematic radiometabolites by changing vulnerable groups to bioisosteres. Herein, we reported the syntheses of 27 new PDE4D inhibitors that have now been assayed in vitro for potency and selectivity of PDE4D inhibition. Through this systematic structure-activity study, 7 high-affinity hits were found and 3 are deemed worthy of radiolabeling. The most potent inhibitor was successfully labeled with carbon-11. These radioligands will be evaluated in monkey with PET imaging in near future. References 1. M.E. Gurney et al, J. Med Chem, 2019, 62, 4884. 2. Y. Wakabayashi, et al ACS Chem Neurosci, 2020, 11, 1311. [11C]MC1 has adequate sensitivity to measure low density cyclooxygenase 2 (COX-2) in healthy human brain X. Yan Introduction: Cyclooxygenase enzymes (COXs) are important targets for neuroinflammation. COX-1 is constitutively present at such high density in brain and periphery that it can be measured with PET using a COX-1 selective radioligand. In contrast, COX-2 is present at low density in healthy tissue but can be markedly upregulated by inflammation. [11C]MC1 is a selective and high affinity radioligand for COX-2. This radioligand has been shown to detect COX-2 elevation in nonhuman primates after intracerebral injection of lipopolysaccharides (LPS) and in patients with rheumatoid arthritis at the symptomatic joints. The purpose of this study was to determine whether COX-2 can be measured by [11C]MC1 in healthy human brain. Methods: Ten healthy participants were injected with [11C]MC1 (730 +/- 48 MBq). Each subject received two brain PET scans for 120 minutes, 2 hours apart - a baseline scan in the morning followed by a blockade scan with celecoxib (600 mg p.o.), a preferential COX-2 inhibitor. Both scans were performed with concurrent arterial sampling. Binding to the enzyme was calculated as total distribution volume corrected for free parent fraction in plasma (VT/fp) using a two-tissue compartment model (2TCM). Receptor occupancy was determined using the Lassen plot. Results: After injection of [11C]MC1, the concentration of brain radioactivity peaked at 4.0 SUV at ~2.8 minutes and declined to 16% of the peak at 120 minutes. The brain time-activity curve was reasonably well-fitted by a 2TCM. VT's were stable after 40 minutes (i.e., reaching within 10% of terminal values at 120 min). However, the measured values of VT after 60 minutes were higher than the fitted values, which might reflect accumulation of small amount of radiometabolites in brain. Specific uptake (VS) was only about 20% of total uptake. Based on the Lassen plot, celecoxib occupied 72% of available COX-2 in the brain. Regions with the highest specific binding were occipital cortex, insula, and prefrontal cortex. Brain distribution of specific binding correlated well with regional mRNA transcripts of the COX-2 gene obtained from the Allen Brain Atlas. Conclusions: The uptake of [11C]MC1 in healthy human brain reflects specific binding to COX-2 based on blockade by celecoxib and based on the correlation between regional VT values and the gene transcript. Our results demonstrate that [11C]MC1 has adequate sensitivity in most healthy subjects to measure the low density of constitutively expressed COX-2. We are now exploring whether [11C]MC1 can measure the upregulation of COX-2 in disorders with neuroinflammation. Thalamic nuclei respond to light pulses in circadian-dependent manner M. Thurman, C Beier, S Hattar Light information is conveyed from the retina to retinorecipient brain regions via two parallel pathways, the image- and non-image-forming visual pathways. A novel discovery has shown that a portion of the ventral lateral geniculate nucleus (vLGN) receives sole innervation from the non-image-forming pathway, similar to the suprachiasmatic nucleus (SCN), the brain's pacemaker. Here, I investigate if the vLGN, and neighboring intergeniculate leaflet (IGL), play a role in pacemaker functions, specifically if they modulate the ability of mice to synchronize their endogenous clocks to the solar day. Previously, only the SCN was thought to respond to light in a circadian-dependent manner, however, my research has found that the vLGN and IGL respond to light in a circadian-dependent manner and that Enkephalin+ cells, which are postsynaptic to the non-image-forming pathway, are responsive to circadian-rhythm-modulating light pulses while Osteopontin+ and Nos1+ cell types are not. In conclusion, the vLGN and IGL show functional responses that are reminiscent of the SCN and therefore these nuclei may modulate circadian photoentrainment. Deficit and Distress Symptom Profiles in Schizophrenia are Influenced by Season of Birth: A Replication I. Silverman, Karen F. Berman, Dwight Dickinson Background Environmental conditions of gestation and early post-natal life have lifelong influences on development and health outcomes. Season of birth (SOB) is a proxy for some of these conditions (e.g., affecting light exposure, activity levels, prevalent allergens/pathogens, etc.). Earlier work has linked spring/summer birth with deficit schizophrenia (Messias et al., 2004). We previously linked spring birth with a PANSS deficit profile (elevated negative and reduced distress symptoms) in a discovery sample of 451 people with schizophrenia. We retested this finding in an independent, 306-person replication sample. Methods As before, we derived PANSS-based composites for negative and distress symptoms. Calendar quarters denoted SOB. GLM univariate and repeated measures analyses, adjusted for age, sex, race and total symptoms, tested for variation in negative and distress symptom patterns, across seasons of birth, in discovery (n=451), replication (n=306) and combined (n=757) samples. Results Results for the replication sample mirrored discovery sample findings (within-subjects, repeated measure analysis of negative/distress patterns: F[3,301]=4.27; p=0.006; ES=.041). In all samples, people born during the second calendar quarter showed the deficit profile while fourth quarter births showed the opposite pattern. Across samples, birth season effects were driven by participants of European ancestry (e.g., replication sample: F[3,214]=7.86; p=5.3E-05; ES=.099). We found a parallel seasonal pattern for cognitive ability in controls, with second quarter births showing lower cognitive ability relative to the other quarters (F[3,1467]=3.68; p=0.01; ES=.008). Conclusion Birth season exerts a limited but significant influence on schizophrenia symptom patterns, as well as on cognitive ability in controls, with spring births (second calendar quarter) experiencing the most disadvantageous outcomes. Naturalistic food categories are driven by subjective estimates rather than objective measures of food qualities M. Carrington, Jason Avery, Alexander Liu, Alex Martin Food-related scientific studies often categorize foods using objective criteria, such as known levels of fat and sugar content (e.g. high-fat, high-sugar foods; low-fat, low-sugar foods), and use these categorizations for further analyses. While they frequently make intuitive sense, it is unclear whether they agree with the ways in which we typically group foods. Do these objective categories correspond to our subjective sense? To address this question, we used an "odd-one-out" triplet task (Hebart et al., 2020), a task which allows us to use participants' qualitative judgments to generate a quantitative measure of the similarity of various objects. In our study, 487 participants on Amazon Mechanical Turk performed this task on 36 food images previously grouped in 4 categories based on levels of fat and sugar (Simmons et al., 2013). We used the data from this task to generate a similarity matrix of these 36 foods. We collected additional data from an online Food and Drug Administration (FDA) database on objective levels of fat, calorie, and sugar content for each food. Through another Amazon Mechanical Turk study, we acquired subjective ratings on how "processed" each food was (100 participants). Overall, subjective ratings of food processing accounted for a greater proportion of the variance of the similarity matrix (r2 = 0.44) than fat content and sugar content combined (r2 = 0.23). Principal Components Analysis (PCA) of the similarity matrix indicated that the first component was most highly related to participants' judgements of how processed the foods were (r = 0.95, p < 0.001, r2 = 0.91), while the second component was most related to sugar content (r = -0.71, p < 0.001, r2 = 0.52). K-means clustering analysis revealed five emergent food groupings along these PC axes: sweets, fats, starches, fruits, and vegetables. Our results suggest that naturalistic categorizations of food are driven mostly by subjective assessments of food qualities, rather than objective food properties, and that these differences should be considered and explored when developing methods for scientific food studies. Avery et al (2021) previously established that it is possible to use fMRI to decode the inferred taste of food pictures within cortical taste-responsive regions. Future studies might explore whether a similar decoding approach could be used to identify the neural substrates associated with the emergent food categories that we identified. Manifold Learning Techniques and fMRI data I. Fernandez, J. Gonzalez-Castillo, K. Lam, D. Handwerker, F. Pereia, P. Bandettini INTRODUCTION Exploratory analyses of brain functional connectivity dynamics during the resting state are challenging because they require researchers to characterize the temporal evolution of high dimensional data while also lacking information about the mental processes that took place as data was being acquired. In the past, we have demonstrated that meaningful low dimensional representations of the temporal dynamics of fMRI functional connectivity (FC) that accompany multi-task scans can be generated with manifold learning techniques. In fact, methods such as Laplacian Eigenmaps and t-SNE can generate interpretable 3D trajectories with clear delineation of scan segments associated with each externally imposed mental state (e.g., task). Importantly, because of the unsupervised nature of these methods, they are amenable to resting state. In the past we have explored this possibility with some level of success, yet additional research is needed to understand how model hyper parameters (e.g., graph generation method, distance metric, etc) can affect the interpretability of the lower dimensional representation generated. Additionally, it is also important to estimate what is the dimensionality of the lower space where the data resides. Here we explore these two important questions. METHODS Datasets: Multi-task data (4 tasks per scan), individual HCP task-based data, and sleep data (A. Arzi & T. Bekinschtein, MRC CBU) are used in these analyses. Pre-processing: multi-task and sleep data was pre-processed with AFNI. For HCP data we relied on the minimally pre-processed version of the data. For analyses that required parcellations, we relied on the Schaefer 2018 atlas. Embedding: We used the scikit-learn implementation of the Laplacian Eigenmaps algorithm to generate 3D representations using different distance metrics (e.g., correlation, Euclidean, cosine) and a range of k-values for the k-nearest neighbor graph generation step. Dimensionality estimation: We used the scikit-dimensions Python library that computes the intrinsic dimension to estimate the dimensionality of the different datasets. Embedding Quality Evaluation: We relied on the scikit-learn implementation of the silhouette index to evaluate the interpretability of the different embedding. RESULTS 1. Hyperparameters can significantly affect the interpretability of resulting embedding. 2. Optimal k depends on the expected duration of the mental states. 3. Data seems to reside in much smaller dimensional space (<100) than its original representation (>1000 for activity, >10,000 for connectivity). 4. Dimensionality varies by data type (e.g., multi-task vs. rest or sleep) CONCLUSION Our work demonstrate that manifold learning techniques can help explore the systems level dynamics of the human brain, yet interpretable embedding may require cautious selection of model hyper parameters. Also, our results suggest that the data indeed resides in a much lower space than the original acquisition space. With these techniques we are one step closer at being able to interpret resting state data with better certainty and clarity. Anatomical tracing with viral vectors delivered with a custom microinjector array in rhesus monkey brain N. Miyazaki, Bing Li, Mark AG Eldridge, Barry J Richmond Many applications of genetically encoded molecular tools - chemogenetics, optogenetics, fluorescent indicators - depend on the precise delivery of viral constructs to target brain regions. Well-described stereotaxic injection methods and a wide variety of transgenic lines have enhanced applications of genetically encoded molecular tools in rodent models. Stereotaxic and hand-held injection methods have been used to infuse viral constructs in the nonhuman primate brain, but often result in sparse or patchy expression. Here, we describe a custom multichannel microfluidic array, used to efficiently infuse FuGE-syn::GFP into area TEO and FuGE-syn::RFP into area TE. Post-operative MRI imaging with manganese contrast and histological analysis confirmed dense viral expression in area TEO. These results provide further evidence that the multichannel microinjector array is a valuable method for the application of genetic tools in the non-human primate. Chemogenetic reversible silencing of rhesus monkey primary visual cortex M. Smith, , Mark Eldridge, Walter Lerchner, Mariko McDougall & Barry Richmond Chemogenetic silencing can be used to selectively and temporarily silence neurons in a target region, making it a flexible and potent tool for neuroscience research. Ivermectin gated chloride channels are one such chemogenetic tool. They have been shown to produce neuronal silencing and behavioral modulation in mice. This study tested the effectiveness of ivermectin-gated neuronal inhibition in the primary visual cortex (V1) cortex of awake behaving nonhuman primates. A modified ivermectin-activated chloride channel was unilaterally expressed in the V1 cortex of one monkey using a mixture of two viruses, AAV2-syn::GluCl2a-YFP and AAV2-syn::GluCl2b-YFP, These lead to expression of the alpha and beta units, respectively, of a glutamate-gated chloride channel. To get virus coverage of the desired region of V1, the viruses were injected at 0.5 µL per second in a 3x3 grid of one hemisphere; in the contralateral hemisphere, a permanent scotoma was created via aspiration removal. The locations in the visual field that corresponded to the placement of the viral construct and scotoma were determined using a visual detection task. Gabor patches of a range of frequencies (16, 8, 4, 2, 1, 0.5, 0.25 and 0.125 cycles/degree) and contrasts (1, 0.64, 0.32, 0.16, 0.08, 0.04, 0.02, 0.01, 0.005) were presented in the regions of the visual field corresponding to the following areas of V1: viral location, the scotoma location and two control locations, symmetrical across the horizontal meridian to the two former regions, respectively. Contrast sensitivity curves were derived from data collected following saline injection and following ivermectin injection. After vehicle injections, contrast sensitivity was intact at the two control sites and the viral site, whereas sensitivity was significantly lower at the scotoma site. Ivermectin injections significantly reduced sensitivity at the viral site but had no significant effect on the other three sites. This preliminary data suggests that the ivermectin-gated chemogenetic system might be a useful method to add the system neuroscientist's molecular toolbox. Local cortical network plasticity amplifies neural responses as animals learn to use novel activity patterns H. Douglas*, Bradley Akitake*, Paul LaFosse, Ciana Deveau, Anna Li, Lauren Ryan, Sam Duffy, Zhishang Zhou, and Mark Histed. * denotes equal contribution To control behavior, neural circuits in the brain must perform a variety of computations, transforming activity that arrives to neurons or networks of neurons into output activity. In sensorimotor tasks, neurons in some brain regions represent aspects of the sensory world, encoding sensory information in neural activity. In order to implement decisions and guide motor actions in such tasks, neural circuits must perform transformations of these activity patterns. In order to understand the neural circuits that implement the computations behind simple perceptual tasks, we created an artificial pattern of activity in a sensory region, primary visual cortex (V1), and trained animals to detect that induced cortical activity. Such activity bypasses the usual sensory inputs into the cortex, and allows study of local processing within V1 and also processing that occurs downstream from it. We stimulated optogenetically while imaging single-neuron responses (AAV-GCaMP8s; AAV- soma-targeted ChrimsonR) during the behavior. We used psychophysical methods to monitor animals' performance while using imaging to track neural responses. We found that animals showed large improvements in performance (perceptual sensitivity) as they gained experience with these artificial stimuli over days to weeks. We then asked what neural changes might support this behavioral learning. On one hand, local circuits in V1 might amplify the inputs we applied optogenetically, or on the other hand, visual cortical responses might remain constant, while the key learning-related changes occur in decision-making circuits downstream of V1. Using two-photon imaging of GCaMP responses while animals performed the task, we found that learning was accompanied by nearly a doubling of the responses of opto-targeted neurons in V1 (221 +/- 59% change in dF/F, mean +/- SD, at 0.06 mW, 5 sessions, N = 2 animals). This neural amplification did not occur in control animals that were optogenetically stimulated outside the behavioral context. Increased sensitivity of the cortical network to optogenetic stimulation resulted in faster reaction times (median -15.4 ms/session, IQR = 18.6, over 7 sessions, N = 9, p < 0.01). This work provides clear evidence that adult cortical recurrent circuitry can change to amplify input. The results suggest that this amplification is triggered by learning and repeated practice with novel activity patterns. Further, the data imply that recurrent connections in cortical circuitry can function to amplify certain salient patterns of input. In ongoing work, we are investigating the local neural circuit changes that produce this amplification, using both theoretical models and cell-specific holographic stimulation to determine what kinds of connectivity or other circuit changes might underlie these effects. Conditional Pupil Size Changes in Marmosets During Active Viewing of Visual Stimuli S. Nti Pupil size change is a physiological response mediated by both intrinsic and extrinsic factors such as arousal and the amount of light, respectively. Changes in pupil size provide relevant information on understanding the fundamental aspects of social interactions, such as responding appropriately to facial expressions, emotions, and the intentions of others. In this study, we investigated whether socially relevant stimuli would elicit larger changes in pupil size than non-social stimuli. We measured pupil size in marmoset monkeys while they were looking at visual stimuli with varying degree of social relevance in two different viewing conditions. In the first condition, a static image of faces and other objects appeared briefly for one second, followed by four seconds of a blank screen. In the second condition, 20-second videos of different contents were played continuously for 2 minutes. Results from the static image condition indicate that pupil dilated more for both human and marmoset face images than for images of other objects. Our future goal is to determine possible relationship between changes in pupil size and neural activity level. The video condition will provide a unique opportunity to look at pupil constriction and dilation in a more naturalistic setting. Linking gametologue expression to sex differences in gene expression and disease A. DeCasien, Kathryn Tsai, Adam Thomas, Siyuan Liu, Armin Raznahan Males and females differ in the prevalence, presentation, and progression of many psychiatric, neurodevelopmental, and neurodegenerative conditions. For example, depression, anxiety and Alzheimer's disease are more prevalent in natal females, whereas attention deficit hyperactivity disorder, autism spectrum disorders, schizophrenia, and Parkinson's disease occur more often in natal males. Given that sex differences in disease susceptibility are likely to (in part) reflect sex differences in neuroanatomy and brain gene expression throughout development, understanding the patterns and drivers of normative brain sex differences may illuminate the underpinnings of sex-biased conditions. It is well established that neurodevelopmental sex differences are largely produced by sex chromosomes, either indirectly via sex hormones (due to SRY driven testis differentiation) or directly via sex-biased expression of genes on the sex chromosomes and of genes whose transcription is influenced by these genes. Of particular interest are the gametologues: genes that have conspicuously retained functional copies on both the X and Y despite having ceased recombination over evolutionary time. Gametologs are only simultaneously expressed in individuals with Y chromosomes and are likely to vary (across pairs) in terms of X-Y functional equivalence - making them especially relevant for the biology of sex-differences. Recent work has demonstrated that gametologue pairs exhibit variable levels of co-expression (between the X and Y copies) and that these patterns are, to some extent, tissue specific. However, we currently lack an understanding of: 1) how patterns of co-expression between X and Y gametologues compare to their patterns of co-expression with other genes across the genome (i.e., 'coupled co-expression' patterns); 2) the mechanisms that drive co-expression versus coupled co-expression; or 3) the functional impacts of differential co-expression with X versus Y gametologues. To address these gaps, we used a large, published human gene expression dataset (GTEx V8) to characterize patterns of co-expression and coupled co-expression for each gametologue pair in >30 tissues. Given that high levels of co-expression may reflect shared regulatory mechanisms between the X and Y copies, we linked levels of promoter sequence similarity to levels of co-expression across gametologue pairs. In addition, given that high levels of coupled co-expression may reflect similar downstream effects of the proteins produced by the X and Y copies, we linked levels of isoform similarity to levels of coupled co-expression across gametologue pairs. Finally, we provide functional annotation of genes that exhibit differential co-expression with the X versus Y gametologues, linking them to specific biological processes, sex-biased diseases, and patterns of sex-biased gene expression. This work improves our understanding of how sex chromosomes influence the human transcriptome more broadly and how these mechanisms may contribute to sex differences in disease. The Relationship between Negative Life Events and Irritability in Youth: A longitudinal study C. Archer, Tatiana Meza-Cervera, Melissa A. Brotman, Katharina Kircanski, Daniel S. Pine, Ellen Leibenluft, & Julia O. Linke Background: Irritability, defined as an increased proneness to anger, is the most common reason for psychiatric consultation in youth; across diagnostic categories irritability is associated with more severe courses (e.g., suicidality) and negative outcomes (e.g., adult psychopathology, low academic attainment). Despite this clinical relevance, irritability is vastly understudied. In particular, the role of environmental variables such as life stress is poorly understood. Here, we investigate the relationship between life events and irritability as a function of syndromal context, and test life events as predictors of the course of irritability. Methods: 540 youth (mean age= 12.89 years, n=283 females, 68% white, 15% Black or African American) that met criteria for at least one mental disorder (anxiety disorders [ANX]: n=134; attention-deficit/hyperactivity disorder [ADHD]: n=101; disruptive mood dysregulation disorder [DMDD]: n=73) or participated as healthy volunteers (HV, n=345) completed the Life Events Checklist and rated irritability with the Affective Reactivity Index repeatedly. We examined relationships between the effect of life events and irritability with Spearman correlation coefficients, which we compared across diagnostic categories. Linear mixed effect models were used to predict the course of irritability from the effect of negative life events in a subset of our sample (n=290). Results: Youth-rated effects of negative life events were positively associated to baseline youth- (rs = .25, p < .001) and parent-rated irritability (rs = .23, p < .001). The course of youth and parent-rated irritability was best modeled as a linear function of time with participants as a random effect. Adding the effect of negative life events as a fixed effect (ARI-Y: = .06, p < .001 ARI-P: = .08, p = .001) improved our model (ARI-Y: 2(1) = 11.4, p < .001; ARI-P: 2(1) = 8.99, p = .001). When we considered the syndromal context, the association between negative life events and youth and parent-rated irritability at baseline was greater in healthy volunteers (ARI-Y: rs = .26, p < .001; ARI-P: rs = .26, p < .001) than individuals with DMDD (ARI-Y: rs = -.04, p = .74; z = 2.33, p = .01; ARI-P: rs = .10, p = .42; z = 1.26, p = .10); there was a trend in the same direction for the other diagnostic groups. Further, the effect of negative life events predicted the longitudinal course of youth and parent-rated irritability in healthy volunteers (ARI-Y: =.04, p < .01; ARI-P: = .05, p < .01), but not in individuals with DMDD (ARI-Y: = .02, p > .05; ARI-P: = .08, p > .05). Discussion: Our findings indicate a positive association between negative life events and irritability, and that youth who experience more negative life events show increased irritability over time. However, our results might only be generalizable to healthy volunteers. In DMDD, where irritability is the hallmark symptom, negative life events appear to have no effect. Future research should aim to replicate this finding, which could indicate differential mechanisms of irritability in affective compared to trauma-related disorders. Nightly sleep influences next-day irritability in a transdiagnostic pediatric sample: An ecological momentary assessment study J. Meigs, A. Chue, R. Naim, A.R. Smith, K. Dombek, S. Shaughnessy, C. Botz-Zapp, H. Grassie, J. Brooks, D.S. Pine, E. Leibenluft, M.A. Brotman, K. Kircanski Irritability is a common and impairing symptom in pediatric psychopathology. Researchers have associated impaired sleep with irritability in the context of specific diagnoses; however, this association has not been examined transdiagnostically, including disruptive mood dysregulation disorder (DMDD) characterized by severe and impairing irritability. Using ecological momentary assessment (EMA) in parent-child dyads, we explored associations between irritability symptoms and total sleep time (TST). 60 youth (M youth age=12.3 years, SD=2.3; 72% male) with varying levels of irritability and including youth with DMDD, and their parents, completed EMA. Participants were prompted for 7 days to assess youth's irritability symptoms, waketimes, and bedtimes. Daily irritability symptoms and TST (in hours) were calculated. Trait irritability was assessed using the youth- and parent-report Affective Reactivity Index (ARI). Data were analyzed using multilevel modeling to account for the nested structure. Child- and parent-report TST did not significantly differ (M youth-report=8.9, SD=1.7; M parent-report=9.2, SD=1.7). Analyses revealed several associations between daily irritability symptoms and TST for parent-report only. For example, lower parent-report TST was associated with higher parent-reported anger the following day (b=-0.21, p<.001). Associations were moderated by trait irritability, such that for youth with higher ARI scores, there was a stronger association in this same direction (b=-0.02, p<.05). Our findings indicate an important link between sleep and irritability symptoms, particularly for youth higher in trait irritability. Results highlight the importance of considering informant effects. Future research should build on this work by quantifying sleep objectively (i.e., actigraphy) and assessing potential bidirectional relationships between irritability and sleep. Universal scaling in the synchronization of cortical cell assemblies E. Capek, T. L. RIBEIRO, P. KELLS, K. SRINIVASAN, S. R. MILLER, E. GEIST, M. VICTOR, A. VAKILI, D. CHIALVO, D. PLENZ Neuronal synchronization is fundamental to many theories on cortex function. Cortical neurons, by preferentially integrating nearby, recurrent activity with distant inputs, establish local and propagated synchrony in the form of oscillations, waves, and neuronal avalanches. These forms of synchrony benefit information processing by flexibly identifying neuronal subgroups; however, they also present with unique limitations. Oscillations emphasize phase-locked firing among neurons, yet the number of different patterns that can be phase-coded per cycle seems to be few. Waves represent compact spatial propagation, which limits their simultaneous occurrence within one region. Neuronal avalanches, in contrast, constitute highly diverse, scale-invariant patterns of synchrony that carry attractively high information capacity. Yet, it is currently not clear whether, at the cellular level, avalanches exhibit precise unfolding of synchronization. The hallmark of neuronal avalanches has been their scale-invariant spatiotemporal statistics quantified by power laws in size and duration. When interpreted within the framework of self-organized criticality, power laws suggest a critical state of cortex that supports diverse and stable, potentially system-wide propagated synchronization. On the other hand, numerous alternative models that differ from synchronization have been proposed for the generation of power laws. In order to discriminate among generative avalanche models, a single scaling exponent chi can be calculated, which captures the relationships between the mean size of avalanches, as well as the corresponding collapse in avalanche shape for different avalanche durations. Here, we revisited the estimation of chi for neuronal avalanches using 2-photon imaging of pyramidal neurons in the cortex of awake transgenic mice. We show that the synchronization and propagation of pyramidal neuron groups exhibits the hallmark of neuronal avalanches during ongoing activity in prefrontal cortex as well as during visually evoked responses in primary visual cortex. Using temporal coarse graining, we demonstrate that chi = 2 and establish a universal avalanche profile in the form of an inverted parabola. These scaling relationships are in line with recent results for LFP-based avalanches in nonhuman primates. Our findings demonstrate universal scaling of synchronized neuronal avalanches to guide the formation of cortical cell assemblies. Synthesis of [11C]PSEM792 a candidate radioligand for use in the development of PSAM-PSEM chemogenetic technology S. Nerella Synthesis of [11C]PSEM792 - a candidate radioligand for use in the development of PSAM-PSEM chemogenetic technology Sridhar G. Nerella, Sanjay Telu, H. Umesha Shetty, Michael Michaelides, Mark Eldridge, Barry J. Richmond, Robert B. Innis, and Victor W. Pike. Introduction. Chemogenetic technology aims to enable the modulation of specific neuronal populations by targeting them to express an exogenous receptor that has been engineered to be activated only by an administered selective agonist. Such technology may become a powerful tool for the development of treatments for neuropsychiatric disorders [1]. PSAM-PSEM is an example of such a new technology. P harmacologically Selective Actuator Modules (PSAMs) are chimeric ligand-gated ion channels comprising an alpha-7 nicotinic acetylcholine receptor (alpha-7-nAChR) ligand binding domain and an ion pore domain of either the excitatory cation-selective 5-HT3 receptor (PSAM-5HT3) or the inhibitory chloride-selective glycine receptor (PSAM-GlyR) [2]. A triple mutant PSAM (termed PSAM4) may be activated by a low dose of varenicline, a recognized anti-smoking drug [3]. PET imaging with the radioligand [18F]ASEM has confirmed PSAM4-GlyR expression and binding in mouse brain. However, brain uptake of [18F]ASEM was very low. Moreover, ASEM is not selective for PSAM4-GlyR because of almost equal affinity for brain alpha-4-beta-2-nAChR. Thus, a more selective and brain-penetrant PET radioligand is needed for verifying and imaging PSAM4 expression in animal models. Variation of varenicline structure has revealed PSEM792 to be an ultrapotent and selective Pharmacologically Selective Effector Molecule (uPSEM) [4]. To meet our aim of producing an improved PET radioligand for assessing PSAM expression in our ongoing chemogenetic - research, we selected PSEM792 as a candidate for labeling with carbon-11 (t1/2 = 20.4 min) and for PET imaging of PSAM4 expression in animal models. Methods. PSEM792 and O-desmethyl precursor (2) for 11C-labeling were each synthesized from the diamine precursor, (1). The labeling agent [11C]iodomethane was prepared from cyclotron-produced [11 C]carbon dioxide as needed. To prepare [11C]PSEM792, the precursor (2) was treated with [11 C]iodomethane in the presence of potassium carbonate-kryptofix in DMF at 80 degrees for 5 min. Aqueous sodium hydroxide (2 M) solution was added to the reaction mixture and heated for 2 min to remove the N -trifluoroacetyl protecting group. The reaction mixture was analyzed by reversed phase HPLC. [11C] PSEM792 was unequivocally identified as a major radioactive product by co-injection with reference PSEM792 onto HPLC, and also by liquid chromatography with tandem mass spectrometry of the associated carrier. Results. No-carrier-added [11C]PSEM792 was obtained in good yield (14%, decay-corrected to end of the radionuclide production) in a radiosynthesis time of ~45 min. Conclusion. [11C]PSEM792 has been synthesized and will be available for evaluation with PET in mice transduced with PSAM4 when ideal separation and formulation for intravenous injection are worked out. References [1] G. J. English et al.. JAMA Neurology, 2015, 72, 1361. [2] D. Atasoy et al., Physiol Rev., 2018, 98, 391. [3] O. Yizhar et al., Trends Pharmacol Sci. 2019, 40, 362. [4] C. J. Magnus et al., Science, 2019, 364, 5282. Dynamic neural-physiological coupling during ecological fear induction in anxious youth G. Ringlein, A. Harrewijn, J. Galbraith, D. Pine, R. Abend Background: Children with anxiety disorders exhibit excessive fear responses in anticipation of threat. While there is growing mechanistic research on aberrant fear responses using standard cognitive tasks, a growing body of research shows that cognitive processes cannot be reduced into additive responses to stimuli but rather are dependent on multisensory input. Naturalistic movies designed to evoke an emotional response during functional imaging may provide a more ecologically valid way to examine fear mechanisms, which may constitute a novel method to identify pathophysiological mechanisms and potential therapeutic targets for anxiety. To explore this possibility, we use a seven-minute animated film to induce a fear response in an ecological setting in youth with and without anxiety. We use skin conductance (SC) as a physiological measure of fear response; specifically, we decompose SC into continuous tonic (slow changing) and phasic (fast changing) signals. Using novel methodology, we then link and these physiological data with continuous fMRI data to characterize the temporal relationship between dynamic functional connectivity within the fear circuitry and identify alterations that relate to pediatric anxiety symptoms. Here, we report on validation of the movie in inducing fear; analyses of fMRI data are ongoing. Objective: We compare tonic and phasic SC collected during 3 epochs: a structural MRI scan (serving as baseline), a pre-movie resting state scan, and the movie scan. Methods: 48 subjects, anxious children (AC) and healthy controls (HC), aged 9-17 (F/M=30/18, age M(SD)=13.77(2.42), AC/HC=20/28) completed the scans. SC was recorded continuously from the medial plantar. Subjects also completed self-reports of worry while scanning. Dedicated software decomposed the SC signal into tonic and phasic components. Non-parametric tests compared SC between and within groups. Results: AC reported significantly more worry than HCs prior to the movie (p<0.05) and showed a significant (p =0.006) drop in worry after the movie. During the baseline scan, we did not see significant (p>0.05) group differences in median tonic or phasic SC. During the anticipatory resting state scan, we see greater tonic SC (p=0.070) and phasic SC (p=0.047) in AC. These effects became more accentuated during the movie (tonic SC: p=0.028), phasic SC: p=0.022). Importantly, there was a significant increase in phasic SC from baseline scan to movie in AC (p=0.002), but not in HC (p=0.603), whereas both AC (p=0.005) and HCs (p=0.023) showed increased tonic SC, indicating differential increases in physiological fear responding. Conclusions: During the movie, tonic SC increased for both groups, while AC only showed significantly more fast-changing SC response during the movie. Additionally, there is a difference in phasic SC between groups during the anticipatory resting state and movie, that is not present at baseline. Finally, AC was associated with greater worry during the movie which was diminished once it was over. This validates that the movie induces a physiological fear response and that elements of which differ between AC and HCs, consistent with the expectation that AC will exhibit differential threat response. We are currently working on analyzing temporal relationships between SC and brain activity in regions implicated in fear processing Distress Associated with Increased Alcohol Use/Misuse During the COVID-19 Pandemic J. Yanes, Ramchandani, Vijay A.; Chung, Joyce Y.; Atlas, Lauren Y. Distress - specifically, how one responds to and/or copes with stress - has important transdiagnostic implications regarding overall mental health (Zvolensky & Hogan, 2013). Distress increases during economic/financial crises (De Goeij et al., 2015), quarantines (Gomez-Duran et al., 2020), and public health emergencies like pandemics (Han et al., 2020). In some cases, distress has been associated with increased alcohol use/misuse [e.g., (Blau et al., 2013; R. L. Brown & Richman, 2012; Kalousova & Burgard, 2014; Ramchandani et al., 2018)]. Given that alcohol use disorder impacts ~15 million Americans (SAMHSA, 2021), three hypotheses were tested: (1) there is a positive association between biweekly measures of recent distress and alcohol use/misuse during the COVID-19 pandemic, and this association varies as a function of baseline alcohol problems, (2) this association is stronger in men versus women, and (3) the association is stronger among respondents who come from households with children (e.g., parents, grandparents). 3,655 participants were enrolled in this online study between April 4 and November 1, 2020. Respondents completed 12 biweekly measurements across 28 weeks (data collection ended May 16, 2020). Respondents were adults (mean-age = 46.64 y (SD = 14.85)), 82% women, 90% Caucasian, and from all 50 US states. Variables of interest were recent distress (i.e., "Please rate the degree of distress that you have had during the past two weeks"), alcohol use/misuse ("During the past two weeks, how much (or how often) have you been bothered by drinking at least 4 drinks in a single day?"), and baseline alcohol problems (AUDIT). Hypotheses were examined using linear mixed-effects models to account for within- and between-subject variance. Models included random intercepts and random slopes. We found that within-subject (p < .001) and between-subject (p = .009) variation in recent distress, as well as baseline alcohol problems (p < .001), were each associated with alcohol use/misuse across considered models. Regarding hypothesis 1, baseline alcohol problems moderated the association between within-subject distress (p < .001), but not between-subject distress (p = .061), and alcohol use/misuse. Regarding hypothesis 2, baseline alcohol problems interacted with both within- and between-subject distress to predict alcohol use/misuse and this association was stronger in men versus women (p = 0.034). And regarding hypothesis 3, this association was stronger in respondents from households with versus without children (p = .034). Importantly, our outcomes are consistent with contemporary perspectives which posit that substance use/misuse reduces negative symptoms stemming from external stressors [e.g., "drinking to cope" (Hawn, Bountress, et al., 2020; Hawn, Cusack, et al., 2020; Koob et al., 2020)]. In this way, alcohol-related coping strategies can promote problematic drinking via negative reinforcement mechanisms (McHugh & Kneeland, 2019; Zorrilla & Koob, 2019). Thus, distress may represent an important link between mental health and compulsive behavior, such as problematic drinking or addiction, whereby changes in one can shape the other. In sum, increased distress-related drinking may represent one important intervention target during/after the COVID-19 pandemic to prevent transitions from occasional alcohol use/misuse to more problematic drinking behavior and/or addiction. Rescue of Avalanche statistics in subsampled critical balanced networks K. Srinivasan Critical networks of neurons show the hallmarks of neuronal avalanches. We demonstrate this in an excitatory/inhibitory (E/I) balanced system of stochastic integrate-and-fire neurons, which exhibits a second-order, continuous phase transition. At this phase transition, the neurons organize as highly diverse, scale-invariant avalanches that quadratically expand in size with duration. Sampling a smaller fraction of this large network makes us deviate from this well-identified regime for critical systems. In this work, we propose a framework to analyze sub-sampled neuronal networks that preserves the critical scaling relationships. Within this framework, we show that the activity follows the universal time course of an inverted parabola and also maximizes the complexity of synchronization in the neuronal population. NIMH Mental Health Impact of the COVID-19 Pandemic Survey: The Influence of Negative Expectations on Physical Symptoms T. Akintola, Joyce Chung, Lauren Atlas A major effect of the COVID-19 pandemic has been wide-spread increase in distress, hopelessness and worries about personal and global outcomes. The combination of these factors has positioned the COVID-19 as a major stressor with an extensive psychosocial impact. Affective factors such as worry and hope can be linked to the generation of self-directed expectations that can influence personal well-being and health outcomes. Previous research shows that expectations can be associated with health outcomes and that changes in expectations can be linked to changes in clinical symptoms, pain, disability and other health outcomes. These include more negative expectations that may result in worse health outcomes, in line with the nocebo phenomenon. Given these findings, it is important to assess how expectations and worry may influence physical symptoms and other clinical and psychological health outcomes. During the COVID-19 pandemic (April 2020-May 2021), we conducted an online study where 3,655 participants were asked to complete biweekly questionnaires over a six-month period about physical and mental health symptoms. These included questions about COVID-specific worry for themselves and others. Participants also reported biweekly if they experienced symptoms associated with COVID-19 infection (e.g., sore throat, cough, fever, fatigue, shortness of breath, loss of taste or smell). Using worry as a proxy for negative expectations, we tested the pre-registered hypothesis that worries about the pandemic and personal health during the pandemic would lead to the reporting of physical symptoms, consistent with the nocebo effect. Specifically, we hypothesized that increased worries in general would be associated with more COVID-19 physical symptoms and that this would be mediated by worries about one's personal health. To address causality, we hypothesized that worry at one time point (T) would be associated with increased number of reported symptoms at the next time point (T+1) and that this relationship would also be mediated by personal worries at time (T). We tested these using single-level and multi-level mediation models in both between and within subjects study designs respectively, controlling for sex, age and number of other comorbidities present. We also excluded those who reported testing positive for COVID-19 at any point. Across subjects, we found that mean worry across the survey period was significantly associated with the average number of physical symptoms reported (p < 2e-16 ***, b = 0.306) and that this relationship was fully mediated by participant's personal worries about becoming infected (p < 0.001, ab = 0.142). Within subjects, personal worry at time (T) was significantly associated with number of symptoms at the next time point (T+1) (p = 0.0165), as hypothesized. There was a marginal association between general worry at time (T) and symptoms at the next time point (p = 0.0635). These findings show that worries and negative expectations may indeed influence the experience of COVID-19 physical symptoms during the ongoing pandemic. They also highlight the importance of evaluating affective and other mental health factors and their possible effects on physical health outcomes. Characterization of Fasciola Cinereum S. Lee, SH Lee, M Cooke, KZ Duan, Elkahloun A, G McGrady, A Mehrnoosh, A Young, K Johnson, A Fahad, SK Williams Avram, WS Young. The arginine vasopressin 1b receptor (Avpr1b) plays an important role in social behaviors including social learning, memory, and aggression, and is known to be a specific marker for the cornuammonis area 2 (CA2) regions of the hippocampus. The Fasciola Cinereum (FC) is an anatomical region in which Avpr1b expressing neurons are prominent,but the functional roles of the FC region have yet to be investigated. Surprisingly, the FC is absent in the BTBR T+tf/J (BTBR) mouse strain used to study core behavioral deficits of autism. The FC appears to be a remnant of the original dorsally located hippocampal anlage: a continuation of the dorsal taenia tecta and induseum griseum and an anterior and dorsal hippocampal rudiment. Anterograde tracing of Avpr1b neurons specific for the FC region showed projections to the induseum griseum, CA2, lacunosum molecular (Lmol) layer of CA1, dorsal fornix, septofibrial nuclei, and lateral septum intermediate (LSI). We have performed single nuclei RNA-Seq (snRNA-seq) using Avpr1b-cre x B6;129Gt(ROSA)26Sortm5 (CAGSun1/sfGFP)Nat/J transgenic mice to selectively isolate the Avpr1b expressing neurons in the FC and dorsal CA2 (dCA2) regions of the hippocampus in both female and male mice. This allowed us to understand how similar FC neurons compare to dCA2 ones and learn the differences in the transcriptomic profiles that might provide insight into their roles in memory formation and social behavior. We have successfully and selectively isolated Avpr1b expressing neurons from both FC and dCA2 regions. Both regions express known dCA2 gene markers including Avpr1b, Amigo2, Rgs14, Map3k15, Cacng5, and Pcp4. When we compared differential gene expression profiles between FC and dCA2 regions, the top markers for dCA2 include the Ttr, Apoe, and Ptgds genes that are involved in amyloid pathology and Alzheimer Disease. Top markers specific for FC include: Mef2c, a gene involved in autism spectrum disorders; Zfp536, a gene involved in central nervous system development. The Tac1 gene, encoding substance P and neurokinin A, is also specific for the FC region. After visualization in a UMAP space, we have further separated these neurons into 7 subclusters of cell types. Although there are similarities in the transcriptomic profiles of FC and dCA2 region, there were subtypes that were represented more prominently by FC region, including subtypes 4, 5 and 7. Interestingly, these subtypes showed low gene expression of the sodium voltage-gated channel alpha subunit 1 (Scn1a). In conjunction with the transcriptomic data, slice electrophysiology recordings demonstrate that a higher threshold of stimuli is required to induce action potentials in Avpr1b neurons in FC compared to dCA2. Additionally, in contrast to the dCA2 region, inhibition of Avpr1b neurons in the FC region by the inhibitory DREADD system during behavior testing did not impair social memory. Therefore, unlike dCA2, the less excitable nature of FC neurons may function more as a regulatory center than as a component in social memory. Overall, our data provide comprehensive transcriptomic profiles and electrophysiological characteristics of subpopulations of neurons in the FC and dCA2 regions that may play important roles in psychiatric disorders such as autism spectrum disorder. Sex-specific Polygenic Contributions to Dopamine Synthesis Capacity in the Putamen Measured in Vivo S. Bansal, Daniel P. Eisenberg, Michael D. Gregory, Madeline Hamborg, Philip D. Kohn, Jasmin Czarapata, Bhaskar Kolachana, Karen F. Berman Background: Dysfunction in striatal presynaptic dopamine synthesis, as measured by [18F]-FDOPA PET, is an important phenotype in neuropsychiatric illnesses such as Parkinson's disease and schizophrenia. Variability of human in vivo dopamine synthesis is likely governed by a complex array of interacting molecules. Since tyrosine hydroxylase (TH) is the rate-limiting enzyme in dopamine synthesis, we hypothesized that cumulative functional genetic variation in known regulators of TH would contribute to dopamine synthesis capacity in the living human brain, as measured with [18F]-FDOPA PET. Methods: Following an extensive literature review, cis-expression quantitative trait loci (cis-eQTLs), based on putamen tissue samples from the GTEx post-mortem gene expression dataset, were identified for literature-supported regulators of TH. Using normalized weighted sums for genotypes at these loci, we generated a cumulative polygenic expression prediction score (PEPS) for each healthy volunteer (n=185, mean age 35.5+/-11.2, 95 females), who provided blood for genotyping and underwent [18F]-FDOPA PET imaging. Quantification of presynaptic dopamine synthesis was achieved using the Patlak graphical analysis technique, yielding Ki, a rate constant reflecting tracer specific uptake and the degree of dopamine synthesis capacity. Voxel-wise tests of association between scores and Ki in the putamen were carried out using SPM software and linear regression models with age, sex, and ancestry-informative principal components as covariates (p<0.05, FDR-corrected). Post-hoc general linear models (GLMs) were run in R to interrogate results for sex and individual gene effects. Results: Individuals with cumulative PEPS predicting greater TH activity in the putamen showed greater FDOPA Ki in the putamen. When PEPS were recalculated using only genes predicted to either up- or down-regulate TH, up-regulator PEPS showed a stronger result (p<0.05, FDR corrected) than the down-regulator PEPS (p<0.01, uncorrected). Post-hoc analyses of the mean Ki from the significant cluster from the cumulative PEPS analysis identified a significant interaction effect of cumulative PEPS score and sex (p<0.003), which was due to females showing a robust genetic effect that was absent in males. To investigate the reliance of these results on the contributions of select individual genes (rather than a cumulative across-genes effect), GLMs were run investigating the effects of individual gene scores on mean FDOPA Ki. A revised PEPS was then generated, which excluded the most significant individual genes (p<0.1). This less-comprehensive model still predicted mean FDOPA Ki in the cluster (p<0.01), suggesting that our results were not solely due to the genes showing the strongest individual effects, but rather reflect a cumulative polygenic effect. Conclusion: Drawing from pre-clinical literature and post-mortem data to model dopamine synthesis in living human brains, this study validates the notion that functional variation in genetic networks affecting dopamine synthesis can explain some of the variance in dopamine synthesis observed in healthy people. Furthermore, such gene-dopamine synthesis relationships may be sexually dimorphic. These results set the stage for further investigation in clinical populations. Galanin Receptor 1 expressing neurons in the prefrontal cortex modulate impulse control C. Senneca, F. Messanvi, V. Visockis, S. Bradley, Y. Chudasama Galanin is a neuropeptide that is expressed in ~80% of Locus Coeruleus (LC) neurons in the rat brain (Hokfelt et al. 1998, Ann N Y Acad Sci. 863:252-263). Galanin Receptor 1 (GalR1) is the predominant receptor in both the rat and human brain, and noradrenergic cells projecting from the LC are the main source of galanin to the prefrontal cortex (Hokfelt et al. 2018, Front Neural Circuits. 12:106). GalR1 has been implicated in the cognitive deficits associated with many disorders, including addiction, depression, and Alzheimer's disease (Weinshenker et al. 2016, Brain Res. 1641(Pt B):320-337). Our own work has demonstrated that the action of GalR1 in the ventral PFC (vPFC) or ventral hippocampus (vHC) strongly influences the degree of impulse control. Specifically, local GalR1 stimulation of the vPFC led to a high rate of impulsive responses, whereas in the vHC it had the opposite effect, making rats more controlled in their responses (Messanvi et al. 2020, Psychopharm 237:291-303). In this study, our goal was to examine the response of GalR1-expressing neurons in the vPFC during performance of a visuospatial target detection task (the 5-Choice task) using optogenetic excitation. Rats were first injected bilaterally with an adeno-associated virus (AAV) expressing CRE under a GalR1 promotor (AAV1-GalR1cre) combined with an AAV expressing ChR2 (or only tdTomato for controls) into the rat vPFC. Optic fibers were also implanted bilaterally into the vPFC. Rats were then trained to a high degree of accuracy (>80%) with a low omission rate (<30%) on the 5-Choice task using an operant touchscreen platform. Then, for half of the trials, a laser at 10, 25, or 40Hz was activated during the interval before stimulus onset, distributed randomly within the session. We found that optogenetic stimulation caused a modest decrease in accuracy at all frequencies but it acted differently on the control of impulsive responses depending on the strength of the excitation. At the low 10Hz excitation, the number of impulsive premature responses increased, but the number of omitted trials decreased. In contrast, the high 40Hz excitation increased the number of omitted trials only. The medium 25Hz excitation had no impact on performance. However, a subset of animals showed a high rate of impulsive premature responses during stimulation at all frequencies. We expect these animals to have fiber placements accurately placed in the vPFC. These preliminary findings indicate that the distribution of GalR1 within the prefrontal cortex circuitry can fine-tune aspects of impulse control mechanisms.