Autism spectrum disorder (ASD) has been implicated with atypical functional connectivity, which may form aberrant organization of functional brain network. While a number of resting-state functional magnetic resonance imaging (rsfMRI) studies have reported long-range under-connectivity, local characteristics of the intrinsic autistic brain activity have not been fully characterized in terms of local connectional profile and amplitude of intrinsic brain activity.

In this study, we acquired rsfMRI data from 50 individuals with ASD and 50 normal controls matched for age (NC: 31.60 ± 7.60; ASD: 30.82 ± 7.39) and gender (male: 43, female: 7 for both groups) using a 1.5 Tesla General Electric Signa system with a phased-array whole-head coil (repetition time (TR): 2000 ms, flip angle: 90°, slice thickness: 4 mm with a 1-mm slice gap, matrix size: 64Χ64, 27 axial slices, 204 volumes). The rsfMRI data were analyzed using local connectivity and fractional amplitude of low-frequency fluctuation (fALFF).

We found that, compared with NCs, participants with ASD showed significant reductions of both local connectivity and fALFF in the right occipito-temporal regions, including the fusiform gyrus and posterior middle temporal gyrus (pMTG). The anatomical overlap between regions identified by the two measures was further validated by conjunction analysis. Furthermore, decline of local connectivity in the right pMTG was significantly associated with a subscale score in autism quotient related to social interaction. Our findings suggest that disrupted local neuronal oscillations and synchronizations in the occpito-temporal regions, especially in the right pMTG, may hamper abilities of individuals with ASD to accomplish successful social interaction.