Linking Brain, Heart, and Behavior in Children: Frontal Electroencephalogram Activity, Respiratory Sinus Arrhythmia, and Internalizing Behaviors.

Internalizing behaviors are characterized by inward-focused emotional distress, which often manifests as symptoms such as depression, anxiety, and negative affect. Previous research has found that physiological correlates of heightened emotional arousal, such as phasic changes in overall frontal electroencephalogram (EEG) alpha activity (FAA) and respiratory sinus arrhythmia (RSA), are independently associated with emotion dysregulation and internalizing behaviors in children. The present study examined whether the interaction of changes in overall FAA and changes in RSA from baseline to a stress induction predicted internalizing behaviors in 152 typically developing children (Mage = 7.82 years, 73 girls, 81.6% White). Results revealed a significant interaction between changes in overall FAA and changes in RSA from baseline to a stressor in predicting children's internalizing behaviors. Specifically, increases in overall FAA from baseline to stress induction were associated with greater internalizing behaviors in children who also exhibited a decrease in RSA from baseline to stress induction. When children exhibited an increase in RSA from baseline to stress induction, increases in overall FAA were associated with relatively fewer internalizing behaviors. Findings highlight that measures indexing central and peripheral nervous system activity may jointly influence stress regulation and contribute to vulnerability to internalizing behaviors in middle childhood.