Resting State Cortical Connectivity Reflected in EEG Coherence in Individuals With Autism

Background Theoretical conceptions of autism spectrum disorder (ASD) and experimental studies of cerebral blood flow suggest abnormalities in connections among distributed neural systems in ASD. Methods Functional connectivity was assessed with electroencephalographic coherence between pairs of electrodes in a high-density electrode array in narrow frequency bands among 18 adults with ASD and 18 control adults in an eyes closed resting state. Results In the θ (3–6 Hz) frequency range, locally elevated coherence was evident for the ASD group, especially within left hemisphere frontal and temporal regions. In the lower α range (8–10 Hz), globally reduced coherence was evident for the ASD group within frontal regions and between frontal and all other scalp regions. The ASD group exhibited significantly greater relative power between 3 and 6 Hz and 13–17 Hz and significantly less relative power between 9 and 10 Hz. Conclusions Robust patterns of over- and under-connectivity are apparent at distinct spatial and temporal scales in ASD subjects in the eyes closed resting state.