Atypical lateralization of intrinsic functional connectivity underlies aberrant face processing in autism spectrum disorders
Lily M. Solomon-Harris1, Naail A. Khan1, Vladyslava Replete1, Cynthia S. Peng2, W. Dale Stevens1, Alex Martin2; 1York University, Toronto, 2National Institute of Mental Health, National Institutes of Health
Autism spectrum disorders (ASD) are characterized by language and social (e.g., face perception) deficits. However, neuroimaging findings regarding the nature and extent of face processing deficits are inconsistent, possibly due to methodological differences in identifying key regions of interest (ROIs). By functionally localizing face ROIs in individual participants using fMRI, we recently demonstrated that individuals with ASD do not show typical rightward lateralization of face-related activation in the posterior superior temporal sulcus (pSTS). Previous work indicates that aberrant face-related activation in the pSTS might be related to reduced intrinsic (i.e., “resting-state”) functional connectivity (RSFC) with the fusiform face area (FFA). Here, we compared RSFC among group-localized vs. individually localized face-ROIs in typically developing (TD) participants and those with ASD. For individually localized ROIs only, TD participants showed stronger RSFC of the right FFA with the right pSTS than left pSTS. Critically, however, participants with ASD showed no difference in RSFC of the right FFA with the left vs. right pSTS, thus demonstrating no hemispheric asymmetry of RSFC among these ROIs, consistent with the lack of hemispheric asymmetry of face-related activation in the pSTS. The pSTS is critical for processing facial-dynamics, multisensory integration, and theory of mind, all of which can be impaired in ASD. Hemispheric lateralization is a critical component of human brain specialization, as for face processing and language skill. Reduced hemispheric specialization of the pSTS could play a critical role in ASD. Furthermore, our results demonstrate that individual ROI localization is crucial for rigorous study of neurodevelopmental disorders.
Topic Area: PERCEPTION & ACTION: Vision