Gray matter volumetric correlates of behavioral activation and inhibition system traits in children: An exploratory voxel-based morphometry study of the ABCD project data.

Approach and avoidance represent two fundamental behavioral traits that develop early in life. Previous studies have examined the neural correlates of approach and avoidance traits in adults and adolescents. Here, using the data set of the Adolescent Brain Cognition Development project, we investigated the structural cerebral bases of behavioral activation system (BAS) and behavioral inhibition system (BIS) in children. We employed voxel-based morphometry to examine how gray matter volumes (GMV) related specifically to BAS and BIS traits in 11,542 children (5491 girls, age 9-10 years) with 648 and 2697 identified as monozygotic twins (MZ) and dizygotic twins/siblings (DZ), respectively. After accounting for the BIS score, higher BAS scores (residuals) were positively correlated with the GMV of the ventral striatum (VS), and the correlation was stronger in MZ than in DZ and unrelated children, with a heritability (h2) of 0.8463. Higher BAS scores were negatively correlated with the GMV of bilateral visual, lateral orbitofrontal, temporal, and inferior frontal cortex, as well as the precuneus. Higher BIS (after accounting for BAS) scores were negatively correlated with the GMVs of the ventral caudate and bilateral putamen/pallidum, hypothalamus, and right anterior insula, and the correlation was stronger in MZ than in DZ and unrelated children, with a heritability of 0.8848. A cluster in the VS showed positive and negative correlation with the BAS and BIS scores, respectively. These findings suggest shared and distinct cerebral volumetric bases of the BAS and BIS traits in children. Whereas both traits have a strong genetic basis, the BAS relative to BIS appears to be more amenable to environmental influences. These findings add to the literature of developmental neuroscience and may help identify genetic risk factors of externalizing and internalizing psychopathology.

Social anxiety, posterior insula activation, and autonomic response during self-initiated action in a Cyberball game.

BACKGROUND: An earlier study characterized the neural correlates of self-initiated actions in a Cyberball game in healthy individuals. It remains unclear how social anxiety may influence these neural processes. METHODS: We examined regional activations to self-initiated actions in 25 adults with low and 25 with high social anxiety (LA and HA, respectively). Skin conductance was recorded concurrently with fMRI. We followed published routines in the analyses of imaging and skin conductance data. RESULTS: We hypothesized that HA as compared to LA individuals would demonstrate increased cortical limbic activations during self-initiated actions (tossing or T > receiving or R trials, to control for motor activities) in social exclusion (EX) vs. fair game (FG) scenario. At a corrected threshold, HA as compared with LA group showed increases in bilateral posterior insula activation during T vs. R trials in EX as compared to FG. Further, HA as compared to LA showed higher skin conductance response to tossing trials during EX as compared to FG. LIMITATIONS: With a limited sample size, we did not examine potential sex effects. Further, we cannot rule out the effects of depression on the findings. CONCLUSIONS: Together, the results suggest that individuals with more severe social anxiety engaged the somatosensory insula to a greater extent and exhibited higher physiological arousal when initiating ball toss during social exclusion in the Cyberball game. Posterior insula response to self-initiated action may represent a biomarker of social anxiety. It remains to be investigated whether interventions to decrease physiological arousal may alleviate social anxiety.

Cerebral responses to self-initiated action during social interactions.

Social interaction involves self-initiated actions that engage subjective awareness of one's own volition. Individuals with social communication needs or social anxiety find it particularly difficult to initiate social interactions. However, extant studies have not specifically addressed how perceived exclusion may influence self-initiated actions during social interaction. As a first step to address this question, we scanned 24 healthy adults participating in a Cyberball game with two fictive players. By contrasting events of observing, receiving, and initiating ball toss during a scenario of fair game (FG) and of exclusion (EX), we examined the neural correlates of self-initiated action during social interactions. Behaviorally, participants were faster in catching but slower in tossing the ball in EX compared with FG, suggesting a burden during self-initiated actions during social exclusion. Tossing versus receiving (or observing) engaged higher activity during EX than FG in the precuneus and angular gyrus, regions that have been widely implicated in theory of mind processing and social emotions. Across subjects these cortical activities correlated positively with the difference between EX and FG in the percentage of trials where participants tossed the ball back to the same player (r = 0.69, p < 0.001). Together, the results suggested that, in healthy adults, social exclusion encumbered and engaged higher posterior cortical activations during self-initiated actions. The findings may facilitate future research of neural markers of social behavioral disorders.