Maternal responses to adolescent positive affect are associated with adolescents' reward neuroanatomy.

The development of reward-based learning and decision-making, and the neural circuitry underlying these processes, appears to be influenced negatively by adverse child-rearing environments characterized by abuse and other forms of maltreatment. No research to-date has investigated whether normative variations in the child-rearing environment have effects on adolescent brain structure. We examined whether normative variations in maternal responses to adolescents' positive affective behavior were associated with morphometric measures of the adolescents' affective neural circuitry, namely the amygdala, orbitofrontal cortex (OFC), and anterior cingulate cortex (ACC). Healthy adolescents (N = 113) participated in laboratory-based interaction tasks with their mothers, and underwent high-resolution (3T) structural magnetic resonance imaging (MRI). The mother-adolescent interactions included a pleasant event-planning interaction (EPI) and a conflictual problem-solving interaction (PSI). Adolescents, whose mothers displayed more punishing responses to their positive affective behavior during both tasks, and only during the PSI, had larger left dorsal ACC and bilateral OFC volumes, respectively. In addition, boys whose mothers evidenced this pattern of behavior during the EPI had larger right amygdala volumes. These results suggest that normative variations in maternal responses to affective behavior are associated with the structural characteristics of adolescents' affective neural circuitry, which may have implications for the development of their social, cognitive and affective functioning.