Mindfulness facets are differentially related with reward processing stages in striatum and alcohol use in adolescence.

Attenuated functional processing of non-drug rewards in striatal regions is an important mechanism in the transition from normal to hazardous alcohol use. Recent interventions seek to enhance nondrug reward processing through mindfulness, a mechanism that targets attention regulation and self-regulatory processes. It is yet unclear which specific aspects of mindfulness and which stages of reward processing are relevant preventive targets, particularly in adolescence, where alcohol use is often initiated and reward relating processing streams undergo continuous maturation. Fifty-four 14- and 16-year-old adolescents (54% female) completed the monetary incentive delay task (MID) during event-related functional magnetic resonance imaging. Alcohol use and dispositional mindfulness facets were measured using self-report instruments. Mindful Attention Regulation was positively associated with anticipatory reward processing in ventral striatum, whereas feedback-related processing in dorsal striatum was associated with the mindfulness facet Body-Listening. Only Attention Regulation was additionally associated with frequency of alcohol consumption and mediated the relationship between functional activation in ventral striatum during reward anticipation and alcohol use. Attention Regulation, beyond other mindfulness facets, might contribute to potentially triggering neural mechanisms of anticipatory, but not feedback-related reward processing and alcohol use, presenting a potential target for preventive efforts in combating transitions to substance-related disorders in adolescents.

How adolescents learn to build social bonds: A developmental computational account of social explore-exploit decision-making.

Building social bonds is a critical task of adolescence that affords opportunities for learning, identity formation, and social support. Failing to develop close relationships in adolescence hinders adult interpersonal functioning and contributes to problems such as loneliness and depression. During adolescence, increased reward sensitivity and greater social flexibility both contribute to healthy social development, yet we lack a clear theory of how these processes interact to support social functioning. Here, we propose synthesizing these two literatures using a computational reinforcement learning framework that recasts how adolescents pursue and learn from social rewards as a social explore-exploit problem. To become socially skilled, adolescents must balance both their efforts to form individual bonds within specific groups and manage memberships across multiple groups to maximize access to social resources. We draw on insights from sociological studies on social capital in collective networks and neurocognitive research on foraging and cooperation to describe the social explore-exploit dilemma faced by adolescents navigating a modern world with increasing access to diverse resources and group memberships. Our account provides important new directions for examining the dynamics of adolescent behavior in social groups and understanding how social value computations can support positive relationships into adulthood.

The role of D1-like dopamine receptors within the ventral tegmental area in the cannabidiol's inhibitory effects on the methamphetamine-induced conditioned place preference in rats.

Cannabidiol (CBD) is a non-psychoactive drug extracted from marijuana. It is well established that CBD attenuates the reinforcing effects of drugs of abuse, although its mechanism of action is not fully understood. The current study tries to clarify the role of D1-like dopamine receptors (D1R) in the ventral tegmental area (VTA) in the inhibitory effects of the CBD on the acquisition and expression of methamphetamine (METH)-conditioned place preference (CPP). In the CPP training, adult male Wistar rats were conditioned with subcutaneous administration of METH (1mg/kg) for five days. Three groups of animals were treated with multiple doses of SCH23390 (as a D1R antagonist; 0.25, 1, and 4µg/0.3µl saline) in the VTA, respectively, before intracerebroventricular (ICV) injection of CBD (10µg/5µl DMSO) in the acquisition phase. In the second experiment of the study, rats received SCH23390 in the VTA before ICV administration of CBD (50µg/5µl DMSO) in the expression of METH CPP. Here, the current study demonstrated that CBD inhibits the acquisition and expression of METH CPP, while microinjection of D1R antagonists (1 and 4µg) into the VTA significantly reduced CBD's suppressive effect on the acquisition and expression of METH place preference. Furthermore, this research demonstrated that either SCH23390 or CBD alone does not lead to place preference in the CPP paradigm. Based on these data, this study suggests that pharmacological manipulations of D1R may alter the CBD's effect on METH-conditioned preference.

Correlation analysis of occupational stress and metabolic syndrome among employees of a power grid enterprise in China.

BACKGROUND: Being in a state of high occupational stress may disrupt the metabolic balance of the body, thus increasing the risk of metabolic diseases. However, the evidence about the relationship between occupational stress and metabolic syndrome was limited. OBJECTIVES: To explore the association between occupational stress and metabolic syndrome (MetS) in employees of a power grid enterprise. METHODS: A total of 1091 employees were recruited from a power grid enterprise in China. Excluding those who failed to complete the questionnaire and those who had incomplete health check-ups, 945 subjects were included in the study. Assessment of occupational stress was used by job demand-control (JDC) and effort-reward imbalance (ERI) questionnaires, respectively. The information on body mass index (BMI), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were collected. The levels of high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), and fasting blood glucose (FBG) in the fasting venous blood samples were measured. Logistic regression analysis and multiple linear regression methods were used to analyze the correlation between JDC and ERI models of occupational stress, metabolic syndrome, and its components, respectively. RESULTS: The prevalence of MetS was 8.4% and 9.9% in JDC and ERI model high occupational stress employees, respectively. ERI model occupational stress and smoking are significantly associated with the risk of MetS. ERI ratio was significantly associated with lower HDL-C levels. Gender, age, marital status, smoking, high-temperature and high-altitude work were significantly associated with metabolic component levels. CONCLUSION: Our study revealed a high detection rate of occupational stress in both JDC and ERI models among employees of a power grid enterprise. ERI model occupational stress, demanding more attention, was associated with the risk of MetS as well as its components such as HDL-C.

Neural correlates of distress and comfort in individuals with avoidant, anxious and secure attachment style: an fMRI study.

Despite a growing literature, experiments directly related to attachment are still needed. We explored brain processes involved in two aspects of attachment, distress and comfort. Seventy-eight healthy adult males with different attachment styles (secure, avoidant, and anxious) viewed distress, comfort, complicity-joy and neutral images (picture database BAPS-Adult) in an fMRI block design. ROIs from the modules described in the functional Neuro-Anatomical Model of Attachment (Long et al. 2020) were studied. Secure participants used more co- and self-regulation strategies and exhibited a higher activation of the reward network in distress and comfort viewing, than insecure participants. Avoidant participants showed the lower brain activations. Their approach and reward modules were the least activated in distress and comfort. Anxious participants presented both higher activations of the approach and aversion modules during complicity-joy. In addition, comfort and complicity-joy were processed differently according to attachment styles and should be differentiated among positive stimuli to disentangle attachment processes.

Misperceiving Momentum: Computational Mechanisms of Biased Striatal Reward Prediction Errors in Bipolar Disorder.

Background: Dysregulated reward processing and mood instability are core features of bipolar disorder that have largely been considered separately, with contradictory findings. We sought to test a mechanistic account that emphasizes an excessive tendency in bipolar disorder to enter recursive cycles in which reward perception is biased by signals that the environment may be changing for the better or worse. Methods: Participants completed a probabilistic reward task with functional magnetic resonance imaging. Using an influential computational model, we ascertained whether participants with bipolar disorder (n = 21) showed greater striatal tracking of momentum-biased reward prediction errors (RPEs) than matched control participants (n = 21). We conducted psychophysiological interaction analyses to quantify the degree to which each group modulated functional connectivity between the ventral striatum and left anterior insula in response to fluctuations in momentum. Results: In participants with bipolar disorder, but not control participants, the momentum-biased RPE model accounted for significant additional variance in striatal activity beyond a standard model of veridical RPEs. Compared with control participants, participants with bipolar disorder exhibited lower insular-striatal functional connectivity modulated by momentum-biased RPEs, an effect that was more pronounced as a function of current manic symptoms. Conclusions: Consistent with existing theory, we found evidence that bipolar disorder is associated with a tendency for momentum to excessively bias striatal tracking of RPEs. We identified impaired insular-striatal connectivity as a possible locus for this propensity. We argue that computational psychiatric approaches that examine momentary shifts in reward and mood dynamics have strong potential for yielding new mechanistic insights and intervention targets.

Bipolar disorder is characterized by extremes in mood and dysregulated reward processing. Moningka and Mason evaluated a neurocomputational model in which mood disturbances arise from an excessive tendency for momentum over recent experiences to bias reward perception. Using model-based functional MRI, the authors found that in contrast to matched control participants, participants with bipolar disorder exhibited fluctuations in reward-related neural responses that are modulated by momentum. They discuss this excessive neural tracking of momentum as one of the mechanisms that may underlie the propensity to enter recursive mood cycles in bipolar disorder.

Ventral striatal-cingulate resting-state functional connectivity in healthy adolescents relates to later depression symptoms in adulthood.

BACKGROUND: Depression is a significant public health concern. Identifying biopsychosocial risk factors for depression is important for developing targeted prevention. Studies have demonstrated that blunted striatal activation during reward processing is a risk factor for depression; however, few have prospectively examined whether adolescent reward-related resting-state functional connectivity (rsFC) predicts depression symptoms in adulthood and how this relates to known risk factors (e.g., childhood trauma). METHODS: At baseline, 66 adolescents (mean age = 14.7, SD = 1.4, 68 % female) underwent rsFC magnetic resonance imaging and completed the Children's Depression Inventory (CDI). At follow-up (mean time between adolescent scan and adult follow-up = 10.1 years, SD = 1.6, mean adult age = 24.8 years, SD = 1.7), participants completed the Childhood Trauma Questionnaire (CTQ) and Beck Depression Inventory (BDI-2). Average rsFC was calculated between nodes in mesocorticolimbic reward circuitry: ventral striatum (VS), rostral anterior cingulate cortex (rACC), medial orbitofrontal cortex, and ventral tegmental area. Linear regressions assessed associations between rsFC, BDI-2, and CTQ, controlling for adolescent CDI, sex assigned at birth, and scan age (Bonferroni corrected). RESULTS: Greater childhood trauma was associated with higher adulthood depression symptoms. Stronger VS-rACC rsFC during adolescence was associated with greater depression symptoms in adulthood and greater childhood trauma. LIMITATIONS: The small sample size, limited depression severity, and seed-based approach are limitations. CONCLUSIONS: The associations between adolescent striatal-cingulate rsFC and childhood trauma and adult depression symptoms suggest this connectivity may be an early neurobiological risk factor for depression and that early life experience plays an important role. Increased VS-rACC connectivity may represent an over-regulatory response on the striatum, commonly reported in depression, and warrants further investigation.

Anterior cingulate cortex lesions impair multiple facets of task engagement not mediated by dorsomedial striatum neuron firing.

The anterior cingulate cortex (ACC) has been implicated across multiple highly specialized cognitive functions-including task engagement, motivation, error detection, attention allocation, value processing, and action selection. Here, we ask if ACC lesions disrupt task performance and firing in dorsomedial striatum (DMS) during the performance of a reward-guided decision-making task that engages many of these cognitive functions. We found that ACC lesions impacted several facets of task performance-including decreasing the initiation and completion of trials, slowing reaction times, and resulting in suboptimal and inaccurate action selection. Reductions in movement times towards the end of behavioral sessions further suggested attenuations in motivation, which paralleled reductions in directional action selection signals in the DMS that were observed later in recording sessions. Surprisingly, however, beyond altered action signals late in sessions-neural correlates in the DMS were largely unaffected, even though behavior was disrupted at multiple levels. We conclude that ACC lesions result in overall deficits in task engagement that impact multiple facets of task performance during our reward-guided decision-making task, which-beyond impacting motivated action signals-arise from dysregulated attentional signals in the ACC and are mediated via downstream targets other than DMS.

Serotonin transporter knockout in rats reduces beta- and gamma-band functional connectivity between the orbitofrontal cortex and amygdala during auditory discrimination.

The orbitofrontal cortex and amygdala collaborate in outcome-guided decision-making through reciprocal projections. While serotonin transporter knockout (SERT-/-) rodents show changes in outcome-guided decision-making, and in orbitofrontal cortex and amygdala neuronal activity, it remains unclear whether SERT genotype modulates orbitofrontal cortex-amygdala synchronization. We trained SERT-/- and SERT+/+ male rats to execute a task requiring to discriminate between two auditory stimuli, one predictive of a reward (CS+) and the other not (CS-), by responding through nose pokes in opposite-side ports. Overall, task acquisition was not influenced by genotype. Next, we simultaneously recorded local field potentials in the orbitofrontal cortex and amygdala of both hemispheres while the rats performed the task. Behaviorally, SERT-/- rats showed a nonsignificant trend for more accurate responses to the CS-. Electrophysiologically, orbitofrontal cortex-amygdala synchronization in the beta and gamma frequency bands during response selection was significantly reduced and associated with decreased hubness and clustering coefficient in both regions in SERT-/- rats compared to SERT+/+ rats. Conversely, theta synchronization at the time of behavioral response in the port associated with reward was similar in both genotypes. Together, our findings reveal the modulation by SERT genotype of the orbitofrontal cortex-amygdala functional connectivity during an auditory discrimination task.

The role of attention and verbal rehearsal in remembering more valuable item-colour binding.

Selectively remembering more valuable information can improve memory efficiency. Such value effects have been observed on long-term memory for item-colour binding, but the possible contributory factors are unclear. The current study explored contributions from attention (Experiment 1) and verbal rehearsal (Experiment 2). Across two experiments, memory was superior for item-colour bindings that were associated with high (relative to low) point values at encoding, both in an immediate test and a delayed re-test. When availability of attentional resources was reduced during encoding, value only influenced immediate and not delayed memory (Experiment 1). This indicates that a transient value effect can be obtained with little attentional resources, but attentional resources are involved in creating a longer lasting effect. When articulatory suppression was implemented during encoding (Experiment 2), value effects were somewhat reduced in the immediate test and abolished in the delayed re-test, suggesting a role for verbal rehearsal in value effects on item-colour binding memory. These patterns of value effects did not interact with encoding presentation format (i.e., sequential vs. simultaneous presentation of objects). Together, these results suggest that attentional resources and verbal rehearsal both contribute to value effects on item-colour binding memory, with varying impacts on the durability of these effects.

Impact of childhood adversity on acute subjective effects of stimulant and opioid drugs: Evidence from placebo-controlled studies in healthy volunteers.

BACKGROUND AND AIMS: Early-life adversities are known to alter drug reward processing in rodents. Despite the well-known link between early adversity and the risk of substance use disorder, few studies have measured how childhood adversity affects human drug reward. Here, we assessed the relationship between historical childhood adversities and responses to single doses of methamphetamine, d-amphetamine or buprenorphine in healthy participants. METHODS: Using a secondary analysis approach, we assessed the impact of childhood adversity on drug effects from three randomised, placebo-controlled studies in which healthy volunteers received methamphetamine (20 mg oral; n = 35), d-amphetamine (20 mg oral; n = 54) or buprenorphine (0.2 mg sublingual; n = 35). Ratings of feeling effect, liking, disliking, feeling high and wanting more of the drug were collected 15-210 min post-administration, and heart rate changes were analysed using random-intercept mixed-effect models. The area under the curve from these and previous studies was calculated to visualise the relationship between childhood adversity severity and drug effects. RESULTS: Greater childhood adversity was associated with reduced feel effects (significant three-way interactions b = -0.07, 95% CI [-0.12, -0.02], p = 0.009), like effects (b = -0.07, 95% CI [-0.13, -0.00], p = 0.038) and feel high (b = -0.06, 95% CI [-0.10, -0.01], p = 0.020) towards the stimulant drugs 90-180 min post-administration. CONCLUSIONS: Childhood adversity was not significantly associated with other subjective or heart rate responses to the drugs. Overall, participants with more childhood adversities reported dampened subjective responses to stimulant drugs, but not to buprenorphine. Future studies should examine the generalisability of these relationships, to identify the mechanisms underlying the link between childhood adversity and drug responsiveness.

MuDE: Multi-agent decomposed reward-based exploration.

In cooperative multi-agent reinforcement learning, agents jointly optimize a centralized value function based on the rewards shared by all agents and learn decentralized policies through value function decomposition. Although such a learning framework is considered effective, estimating individual contribution from the rewards, which is essential for learning highly cooperative behaviors, is difficult. In addition, it becomes more challenging when reinforcement and punishment, help in increasing or decreasing the specific behaviors of agents, coexist because the processes of maximizing reinforcement and minimizing punishment can often conflict in practice. This study proposes a novel exploration scheme called multi-agent decomposed reward-based exploration (MuDE), which preferably explores the action spaces associated with positive sub-rewards based on a modified reward decomposition scheme, thus effectively exploring action spaces not reachable by existing exploration schemes. We evaluate MuDE with a challenging set of StarCraft II micromanagement and modified predator-prey tasks extended to include reinforcement and punishment. The results show that MuDE accurately estimates sub-rewards and outperforms state-of-the-art approaches in both convergence speed and win rates.

Multivariate Neural Patterns of Reward and Anxiety in Adolescents with Anorexia Nervosa.

People with anorexia nervosa (AN) commonly exhibit elevated anxiety and atypical reward responsiveness. To examine multivariate neural patterns associated with reward and the impact of anxiety on reward, we analyzed fMRI data from a monetary reward task using representational similarity analysis, a multivariate approach that measures trial-by-trial consistency of neural responses. Twenty-five adolescent girls with AN and 22 mildly anxious controls lacking any history of AN were presented personalized anxiety-provoking or neutral words before receiving a reward, and neural response patterns in reward regions were analyzed. Consistent with our preregistered hypothesis, AN participants showed lower representational similarity than controls during neutral-word rewarded trials. Within groups, controls showed significant representational similarity in reward circuit regions including the left nucleus accumbens, left basolateral amygdala, and left medial orbitofrontal cortex, which were not observed in AN. Further, reward-related prefrontal cognitive control areas - left ventrolateral prefrontal cortex and left dorsolateral prefrontal cortex - showed significant representational similarity in both groups, but a larger spatial extent in controls. Contrary to predictions, there were no significant between-group differences for the effects of anxiety-words on reward representational similarity, and representational similarity did not predict longitudinal symptom change over six months. Overall, the results demonstrate relatively inconsistent trial-by-trial responses to reward receipt in the neutral state in AN compared with controls in both reward circuit and cognitive control regions, but no significant differential effects of anxiety states on reward responses. These results add to dynamic understandings of reward processing in AN that have potential implications for planning and guiding reward-focused interventions.

The role of food reward in the associations between weight-based discrimination and feeding practices among caregivers of young children.

Certain caregiver feeding practices, including restrictive feeding for weight control, restrictive feeding for health, emotion regulation feeding, and reward feeding, are known to negatively influence short- and long-term child eating and health outcomes. Beyond body size, the precise psychosocial characteristics of caregivers more likely to engage in such feeding practices are unknown. In particular, caregivers who have experienced discrimination based on their weight, who have internalized those biased beliefs, or who find food to be very rewarding may be more likely to use restrictive or controlling feeding practices. The present study investigated the associations among experiences of weight-based discrimination, internalized weight bias, and food reward (i.e., reward-based eating drive) with use of restriction for weight control, restriction for health, emotion regulation feeding, and reward feeding in an online US sample of caregivers (M = 35.27 ± 9.08 y/o) of 2-5 year-old children (N = 305). About half (50.8%) of respondents self-identified as women and most as non-Hispanic (88.5%) and White (75.1%). There were significant positive correlations among caregivers' experience of weight-based discrimination, internalized weight bias, and use of all four feeding practices. Regression results showed that caregivers' food reward moderated the main effect of weight-based discrimination on restrictive feeding for weight control and emotion regulation feeding, such that caregivers who were high in food reward and who experienced discrimination were most likely to engage in these feeding practices. These results can inform interventions aimed at improving child food environments and health.

The burdens and benefits of managing and engaging: a diary study approach to person-centred risk assessment of top executives and works council members.

The present diary study investigates the impact of daily effort-reward imbalance (ERI), subjective stress and the cortisol awakening response (CAR) as an objective measure on work engagement of top managers and high-level works council members (N = 45) on three consecutive working days. In the scope of psychosocial risk assessment, we argue that focusing on ERI as a generalized work characteristic might be more suitable for work re-design of higher leadership positions because of their highly dynamic and unpredictable psychosocial work characteristics, while at the same time having more access to job resources. The analyses reveal that both baseline and daily ERI, as well as subjective stress, influence work engagement. Our results suggest that interventions to reduce daily levels of ERI may improve the work environment of top managers and works councils by promoting work engagement and related positive health outcomes in the scope of person-centred risk assessment.

The relationship between effort-reward imbalance and quality of working life among medical caregivers: mediating effects of job burnout.

Background: To determine the relationship between effort-reward imbalance (ERI) and quality of working life (QWL) among medical caregivers and the mediating role of job burnout. Methods: This was a cross-sectional survey. A total of 787 medical caregivers at seven hospitals from Sichuan and Chongqing, China, between May to September 2023 were included in this observational study. The General Information Questionnaire, Effort-Reward Imbalance Questionnaire (ERI), Maslach Burnout Inventory-General Survey (MBI-GS), and Quality of Working Life Scale (QWL7-32) were used for data collection. SPSS 26.0 and PROCESSv3.3 were used for all data analyses, including descriptive statistics. Results: A total of 820 questionnaires were distributed, of which only 787 were valid (return rate; 95.98%). The QWL score of medical caregivers was 126.94 ± 16.69. However, QWL scores were significantly different depending on age, number of children, family support status, department, years of experience, night shift status, number of night shifts per month, number of hours worked per day, monthly income, and occurrence of errors or adverse events (p < 0.05). Furthermore, job burnout and ERI were negatively correlated with QWL (p < 0.01). Job burnout mediated (95% CI = -0.365, -0.260) the relationship between ERI and QWL, accounting for 58.65% of the total effect. Conclusion: Medical caregivers have a medium level of QWL. Job burnout partially mediates the relationship between ERI and QWL. Medical caregiver managers can improve QWL by directly intervening in occupational stress and indirectly intervening in job burnout.

Counteract Anhedonia! Introducing an Online-Training to Enhance Reward Experiencing - A Pilot Study.

Background: Anhedonia is a risk factor for a severe course of depression but is often not adequately addressed in psychotherapy. This study presents the Training to Enhance Reward Experience (T-REx), a novel self-help approach that uses savoring and mental imagery to target impairments in reward experience associated with anhedonia. We aimed to examine feasibility and acceptability of T-REx and exploratively investigated its effects on anhedonia and other clinical variables. Method: In an online, randomized controlled trial, 79 subjects participated for five days in T-REx or the active control condition Gratitude Writing (GW). We assessed changes in anhedonia, depression, and active behavior at inclusion, after the waiting period, post-intervention and at follow-up. The intervention effects were examined for the full sample and an anhedonic sub-sample. Results: T-REx and GW were equally feasible and clearly accepted by the sample. Both interventions significantly reduced depressive symptoms and increased behavioral activation. Although there was no significant main effect of the interventions, between-group differences were observed for depressive symptoms and active behavior at post-intervention and follow-up, favoring T-REx. Further, within-group changes for T-REx were larger than for GW. The observed effects had a greater magnitude in the anhedonic sub-sample, suggesting that individuals with more pronounced anhedonic symptoms derived greater benefit from the interventions. Discussion: This first study of T-REx provides promising results that should prompt further investigations of T-REx in clinical samples. The results suggest that T-REx has a positive effect on depression symptoms and active behavior. Further, its potential as a valuable adjunct to behavioral activation interventions is discussed.

Unravelling the origin of the reward positivity: a human intracranial event-related brain potential study.

The reward positivity (RewP) is an event-related brain potential (ERP) component that emerges approximately 250 to 350 milliseconds (ms) after receiving reward-related feedback stimuli and is believed to be important for reinforcement learning and reward processing. Although numerous localization studies have indicated that the anterior cingulate cortex (ACC) is the neural generator of this component, other studies have identified sources outside of the ACC, fuelling a debate about its origin. Because the results of EEG and MEG source localization studies are severely limited by the inverse problem, we addressed this question by leveraging the high spatial and temporal resolution of intracranial EEG. We predicted that we would identify a neural generator of the RewP in the caudal ACC. We recorded intracranial EEG in 19 refractory epilepsy patients who underwent invasive video-EEG monitoring at Ghent University Hospital, Belgium. Participants engaged in the virtual T-maze task (vTMT), a trial-and-error task known to elicit a canonical RewP, while scalp and intracranial EEG were simultaneously recorded. The RewP was identified using a difference wave approach for both scalp and intracranial EEG. The data were aggregated across participants to create a virtual "meta-participant" that contained all the recorded intracranial ERPs (iERPs) with respect to their intracranial contact locations. We used both a hypothesis-driven (focused on ACC) and exploratory (whole-brain analysis) approach to segment the brain into regions of interest (ROI). For each ROI, we evaluated the degree to which the time course of the absolute current density (ACD) activity mirrored the time course of the RewP, and confirmed the statistical significance of the results using permutation analysis. The grand average waveform of the scalp data revealed a RewP at 309 ms after reward feedback with a frontocentral scalp distribution, consistent with the identification of this component as the RewP. The meta-participant contained iERPs recorded from 582 intracranial contacts in total. The ACD activity of the aggregated iERPs were most similar to the RewP in left caudal ACC, left dorsolateral prefrontal cortex, left frontomedial cortex, and left white matter, with the highest score attributed to caudal ACC, as predicted. To our knowledge, this is the first study that uses intracranial EEG aggregated across multiple human epilepsy patients and current source density analysis to identify the neural generator(s) of the RewP. These results provide direct evidence that the ACC is a neural generator of the RewP.

Decreased Serum Cocaine- and Amphetamine-Regulated Transcript Level in Internet Gaming Disorder.

OBJECTIVE: Vulnerability to internet gaming disorder (IGD) has increased as internet gaming continues to grow. Cocaine- and amphetamine-regulated transcript (CART) is a hormone that plays a role in reward, anxiety, and stress. The purpose of this study was to identify the role of CART in the pathophysiology of IGD. METHODS: The serum CART levels were measured by enzyme-linked immunosorbent assay, and the associations of the serum CART level with psychological variables were analyzed in patients with IGD (n=31) and healthy controls (HC) (n=42). RESULTS: The serum CART level was significantly lower in the IGD than HC group. The IGD group scored significantly higher than the HC group on the psychological domains of depression, anxiety, the reward response in the Behavioral Activation System and Behavioral Inhibition System. There were no significant correlations between serum CART level and other psychological variables in the IGD group. CONCLUSION: Our results indicate that a decrease in the expression of the serum CART level is associated with the vulnerability of developing IGD. This study supports the possibility that CART is a biomarker in the pathophysiology of IGD.

Distinct subcircuits within the mesolimbic dopamine system encode the salience and valence of social stimuli.

The mesolimbic dopamine (DA) system (MDS) is the canonical "reward" pathway that has been studied extensively in the context of the rewarding properties of sex, food, and drugs of abuse. In contrast, very little is known about the role of the MDS in the processing of the rewarding and aversive properties of social stimuli. Social interactions can be characterized by their salience (i.e., importance) and their rewarding or aversive properties (i.e., valence). Here, we test the novel hypothesis that projections from the medial ventral tegmental area (VTA) to the nucleus accumbens (NAc) core codes for the salience of social stimuli through the phasic release of DA in response to both rewarding and aversive social stimuli. In contrast, we hypothesize that projections from the lateral VTA to the NAc shell codes for the rewarding properties of social stimuli by increasing the tonic release of DA and the aversive properties of social stimuli by reducing the tonic release of DA. Using DA amperometry, which monitors DA signaling with a high degree of temporal and anatomical resolution, we measured DA signaling in the NAc core or shell while rewarding and aversive social interactions were taking place. These findings, as well as additional anatomical and functional studies, provide strong support for the proposed neural circuitry underlying the response of the MDS to social stimuli. Together, these data provide a novel conceptualization of how the functional and anatomical heterogeneity within the MDS detect and distinguish between social salience, social reward, and social aversion. Significance Statement: Social interactions of both positive and negative valence are highly salient stimuli that profoundly impact social behavior and social relationships. Although DA projections from the VTA to the NAc are involved in reward and aversion little is known about their role in the saliency and valence of social stimuli. Here, we report that DA projections from the mVTA to the NAc core signal the salience of social stimuli, whereas projections from the lVTA to the NAc shell signal valence of social stimuli. This work extends our current understanding of the role of DA in the MDS by characterizing its subcircuit connectivity and associated function in the processing of rewarding and aversive social stimuli.