Maternal buffering of human amygdala-prefrontal circuitry during childhood but not during adolescence.

Mature amygdala-prefrontal circuitry regulates affect in adulthood but shows protracted development. In altricial and semialtricial species, caregivers provide potent affect regulation when mature neurocircuitry is absent. The present investigation examined a potential mechanism through which caregivers provide regulatory influences in childhood. Children, but not adolescents, showed evidence of maternal buffering, such that maternal stimuli suppressed amygdala reactivity. In the absence of maternal stimuli, children exhibited immature amygdala-prefrontal connectivity. However, in the presence of maternal stimuli, children's connectivity was more mature, resembling adolescents' connectivity. Children showed improved affect-related regulation in the presence of their mothers. Individual differences emerged, with greater maternal influence on amygdala-prefrontal circuitry associated with stronger mother-child relationships and maternal modulation of behavioral regulation. These findings suggest a neural mechanism through which caregivers modulate children's regulatory behavior by inducing more mature connectivity and buffering against heightened reactivity. Maternal buffering in childhood, but not adolescence, suggests that childhood may be a sensitive period for amygdala-prefrontal development.