Amygdala – Ventral Prefrontal Network Influences on Emotion Regulation in Adolescence and Adulthood.

Abstract

Appropriate emotion regulation is a necessary mechanism for social development. The amygdala is a brain structure involved in emotion perception and processing whereas the ventral prefrontal cortex (vPFC) has been linked to the regulation of amygdala activity. The purpose of this dissertation is to investigate the functional correlates of developmental and genetic aspects in the amygdala -vPFC network. Chapter 2 of this dissertation focuses on the effects of white matter integrity on amygdala activation in response to emotional faces. We conducted diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) analyses in a sample consisting of typically developing (TD) adolescents and young adults. This chapter reports three main findings. First, participant age predicted amygdala activation in response to faces in general, but not in the comparison of specific faces. Specifically, younger subjects exhibited greater amygdala activation than older subjects. Second, white matter integrity increased with age in our cross-sectional sample of adolescents and young adults. Third, higher white matter integrity was related to lower amygdala activation in response to both fearful and sad faces compared to neutral faces, but not to happy vs. neutral faces. Chapter 3 investigated the contribution of 5-HTTLPR variant genotype on amygdala- vPFC functional connectivity in adolescents with autism spectrum disorder (ASD). We hypothesized a diagnosis (ASD vs. TD) by genotype (low vs. higher expressing serotonin transporter gene variant) interaction on amygdala-vPFC connectivity. We expected greater connectivity in individuals with ASD and low expressing 5-HTTLPR genotypes, in response to emotional faces (fearful, happy, and sad) compared to neutral faces. Individuals in the low expressing ASD group showed significantly greater connectivity than the ASD higher expressing group and both TD groups in response to happy relative to neutral faces. The interaction was not observed in response to sad and fearful faces.With the use of fMRI, DTI, and genetic work, the present dissertation contributes to the understanding of emotion regulation development in typically developing individuals as well as in individuals with ASD.