Baseline brain function in the preadolescents of the ABCD Study.

The Adolescent Brain Cognitive Development (ABCD) Study® is a 10-year longitudinal study of children recruited at ages 9 and 10. A battery of neuroimaging tasks are administered biennially to track neurodevelopment and identify individual differences in brain function. This study reports activation patterns from functional MRI (fMRI) tasks completed at baseline, which were designed to measure cognitive impulse control with a stop signal task (SST; N = 5,547), reward anticipation and receipt with a monetary incentive delay (MID) task (N = 6,657) and working memory and emotion reactivity with an emotional N-back (EN-back) task (N = 6,009). Further, we report the spatial reproducibility of activation patterns by assessing between-group vertex/voxelwise correlations of blood oxygen level-dependent (BOLD) activation. Analyses reveal robust brain activations that are consistent with the published literature, vary across fMRI tasks/contrasts and slightly correlate with individual behavioral performance on the tasks. These results establish the preadolescent brain function baseline, guide interpretation of cross-sectional analyses and will enable the investigation of longitudinal changes during adolescent development.

Sensation seeking and risk-taking propensity as mediators in the relationship between childhood abuse and HIV-related risk behavior.

OBJECTIVES: Although a wealth of literature suggests that childhood physical, emotional, and sexual abuse are related to later-life HIV-related risk behaviors, few studies have explored disinhibition (e.g., impulsivity, risk-taking propensity, and sensation-seeking) as a risk factor in this relationship. METHOD: This cross-sectional study examined impulsivity, risk-taking propensity, and sensation seeking as mediators in the relationship between abuse history and engagement in HIV-related risk behaviors among a sample of 96 inner-city African American adolescents. RESULTS: Findings indicated that abuse history was positively related to self-reported engagement in HIV-related risk behaviors (B=.027, SE .008, beta=.32, sr(2)=.105, p=.001), as well as risk-taking propensity (B=.35, SE .11, beta=.30, sr(2)=.090, p=.003) and sensation seeking (B=.17, SE .05, beta=.35, sr(2)=.124, p=.0004). Abuse history was not related to impulsivity. Further, while sensation-seeking and risk-taking propensity (to a lesser extent) mediated this relationship, impulsivity did not. CONCLUSIONS: These findings provide an initial step in the examination of the mechanisms underlying the relationship between childhood abuse and engagement in HIV-related risk behaviors.