THE MODERATING ROLE OF AMYGDALAR AND HIPPOCAMPAL ACTIVATIONS IN THE EFFECTS OF FAMILY REARING ENVIRONMENTS ON YOUTH ADJUSTMENT

Family rearing experiences are critical to youths’ socioemotional and behavioral development. Supportive family environments contribute to positive youth adjustment. In contrast, youth exposed to adverse rearing experiences are at increased risk for developing psychopathology. Despite the documented effects of rearing environments on developmental outcomes, youth often show different responses even to similar family experiences. These differential responses are attributed to interactions between the environments (positive or negative) and youths’ neurobiological architecture. Specific neurobiological traits potentiate the effect of rearing environments by rendering youth to be more biologically sensitive and behaviorally responsive to caregiving experiences. Thus, they are either more vulnerable to the harmful impacts of adverse rearing experiences or benefiting more from positive environments. Despite empirical evidence on youths’ differential responses to family influences, the underpinning neural architecture remains unclear. The present dissertation investigated the neurobiological mechanisms underlying youths’ differential behavioral reactivity to family rearing environments, with the amygdala and hippocampus as the key neurobiological foci. The activations of these two subcortical brain regions in response to emotional stimuli were hypothesized to moderate the linkage between rearing environments and youth adjustment.

This dissertation included two studies that methodologically complemented each other. The first study employed a large, nationally representative, and longitudinal dataset of the Adolescent Brain Cognitive Development study (N = 11,875). This dataset granted substantial statistical power to test the study hypotheses. The second study used a modest sample with multi-method and multi-reporter assessments from at-risk families in rural Georgia (N = 123). This study employed a rigorous measurement tool to assess the full continuum (from negative to positive) and dimensionality of rearing environments. Results showed that left amygdalar and hippocampal activations during emotional processing significantly exacerbated the effects of rearing environments on youth adjustment. Youth who evinced higher levels of left amygdalar and hippocampal activations and reported adverse family environments showed elevated problem behaviors. However, with heightened left amygdalar and hippocampal activations, youth also exhibited more adaptive responses to supportive rearing experiences. The findings of this dissertation may assist in tailoring prevention and intervention programs to target the most vulnerable and responsive youth for interventive practices.