Neural Substrates of Emotional Face Processing Across Development in Autism Spectrum Disorder

Individuals with Autism Spectrum Disorder (ASD) demonstrate striking impairment in social interactions. One of the most integral skills to successful social interactions is the ability to accurately perceive and interpret others’ faces and their emotional expressions. In typical development, emotional face processing has an extended developmental trajectory, which is likely due to the protracted maturation of underlying neural mechanisms. However, there is a lack of studies investigating the functional maturation of the neural substrates of emotional face processing in ASD. The objective of this thesis was to gain a greater understanding of the neural substrates underlying maturational patterns and changes in emotional processing in individuals with and without ASD using magnetoencephalography from childhood (Study 1) to adolescence (Study 2), and finally, to adulthood (Study 3). The first study showed general atypical processing of emotional faces in children with ASD, relative to typically developing children as well as distinct processing of emotions within groups. These findings suggest poor modulation of the toggling between the default mode network and emotional face processing as well as discrepant salience of facial expressions of anger and happiness to children with ASD relative to typically developing children. The second study showed discrepant neural activity in adolescents with ASD, relative to controls, during angry and happy face processing in areas of the ‘social brain’, indicating that adolescents with ASD show atypical ability to recruit and integrate these regions to the same extent as typically developing adolescents. The final study demonstrated that young adults with ASD show atypical recruitment of ‘traditional’ affect processing areas and that difficulties in deriving social rewards and attributing salience to faces as well as an immature threat processing system may contribute to deficits in emotional face processing. Collectively, these studies show disturbances in the functional neural systems underlying facial affect processing are present in childhood in ASD and persist in adolescence and young adulthood. The results of these studies have clinical implications in terms of facial affect interventions to facilitate social skills in individuals with ASD.Ph.D