Background: Autistic disorder is a neurodevelopmental syndrome characterized by impaired social deficits [1].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 [2].Most of the previous neuroimaging evidence has concentrated on local functional or structural abnormalities of the amygdala in autism,rather than on its integrated role as part of larger brain networks [3,4].Based on the amygdala-related findings associated with sociocommunicative symptoms,we hypothesized that the resting-state functional connectivity patterns of the amygdala would be altered in adolescents with autism.Methods: This study utilized sixty-six adolescent subjects(31 participants with autism and 35 healthy controls,12 to 18 years old)from two independent datasets(UCLA and Leuven)of the Autism Brain Imaging Data Exchange(ABIDE).For each dataset,whole-brain resting-state functional connectivity maps seeded in the bilateral amygdala were calculated and compared between patient and control groups using a random effect two-sample t-test in a voxel-wise manner within the union regions of random effect one-sample t-test of the two groups.We finally extracted the overlap regions of the two datasets as the regions showing significant difference between two groups.In addition,we examined the relation between symptom severity and altered amygdala functional connectivity to establish a more precise link between behavior and brain function in this population.Results: Compared with healthy controls,adolescents with autism showed decreased functional connectivity between the left amygdala and the right thalamus,and increased functional connectivity between the right amygdala and the right precentral gyrus and postcentral gyrus in both datasets(Figure 1 A).Furthermore,the strength of the functional connectivity between the left amygdala and the right thalamus was negatively related to social communication deficits in autism(r =-0.48,p = 0.04)(Figure 1 B).Conclusion: These findings support the Amygdala Theory of Autism,demonstrating altered functional connectivity patterns associated with the amygdala in autism.More generally,the correlation of amygdala functional connectivity with clinical symptom severity indicates the potential of abnormal amygdala-related functional integration to serve as a biomarker for evaluating sociocommunicative impairments for diagnosis.