Decreased amygdala functional connectivity in adolescents with autism: A resting-state fMRI study

The human brain undergoes dramatic changes in amygdala-related functional connectivity network during adolescence. Given that the amygdala is a vital component of the "social brain", the Amygdala Theory of Autism has been proposed to account for atypical patterns of socio-emotional behavior in autism. Most of the previous neuroimaging evidence has concentrated on local functional or structural abnormalities of the amygdala in relation to social deficits in autism, rather than on its integrated role as part of larger brain networks. To examine whether functional integration pattern of the amygdala is altered in autism, the current study examined sixty-five adolescent subjects (30 autism and 35 healthy controls, 12-18 years old) from two independent datasets (UCLA and Leuven) of the Autism Brain Imaging Data Exchange. Whole-brain resting-state functional connectivity maps seeded in the amygdala were calculated and compared between patient and control groups. Compared with healthy controls, adolescents with autism showed decreased functional connectivity between the amygdala and subcortical regions in both datasets, including the bilateral thalamus and right putamen. These findings support the Amygdala Theory of Autism, demonstrating altered functional connectivity pattern associated with the amygdala in autism, and provide new insights into the pathophysiology of autism.