Increased amygdala activation is related to heart rate during emotion processing in adolescent subjects

Emotions have been conceptualized as representations of bodily responses to a stimulus that critically involves the autonomic nervous system (ANS). An association between amygdala activation and ANS activity has been shown in adults. However, to date, no studies have demonstrated this association in adolescents. Examining the interaction between the ANS and amygdala in healthy adolescents may provide information about age-related changes in the association between amygdala activation and ANS measures. Therefore, the aim of this study was to examine the relationship between amygdala activation and heart rate in normal adolescents. Eighteen 12- to 17-year old adolescents participated. Heart rate data was collected during functional magnetic resonance imaging while subjects performed a facial expression matching task that reliably activates the amygdala. Adolescents showed significant amygdala activation for all facial expressions relative to the shape-matching, control task. Moreover, the degree of activation in the right amygdala for Fearful faces was significantly correlated with heart rate (Spearman's rho=0.55, p=0.018, two-tailed). This study shows that amygdala activity is related to heart rate in healthy adolescents. Thus, similar to adults, adolescents show a coupling between processing emotional events and adjusting the ANS accordingly. Furthermore, this study confirms previous adolescent studies showing amygdala activation to Fearful, Angry, and Happy faces. Finally, the results of the present study lay the foundation for future research to investigate whether adolescents with mood or anxiety disorders show an altered coupling between processing emotionally salient events and ANS activity.