Amygdala response to mother.

In altricial species, like the human, the caregiver, very often the mother, is one of the most potent stimuli during development. The distinction between mothers and other adults is learned early in life and results in numerous behaviors in the child, most notably mother-approach and stranger wariness. The current study examined the influence of the maternal stimulus on amygdala activity and related circuitry in 25 developing children (n = 13) and adolescents (n = 12), and how this circuitry was associated with attachment-related behaviors. Results indicated that maternal stimuli were especially effective in recruiting activity in the left dorsal amygdala, and activity in this amygdala region showed increased functional connectivity with evaluative and motor regions during viewing of maternal stimuli. Increases in this left dorsal amygdala activity and related amygdala-cortical functional connectivity were associated with increased mother-approach behaviors as measured by in-scanner behavioral responding and out-of-scanner child-report. Moreover, age-related changes in amygdala activity to strangers statistically mediated the developmentally typical decline in stranger wariness seen across this period. These results suggest that mother-induced behaviors are enacted by maternal influence on amygdala-cortical circuitry during childhood and adolescence.