Objectives: To compare the patterns of functional correlations in perceptual brain regions between autistic and non-autistic individuals, during rest.
Methods: Our sample included 19 autistic and 21 non-autistic participants, matched for age, sex, manual preference and IQ. Using a 3T MRI system, we examined interregional BOLD-contrast cortico-cortical and thalamocortical bivariate correlations in time series collected over a 10 min period while participants were instructed to remain still with eyes closed. We examined a collection of cortical and subcortical seed regions involved in early sensory processing, including the thalami and primary cortical areas in visual, auditory, olfactory and somatosensory systems. Coordinates for the seed regions were selected with masks obtained from the AAL atlas.
Results: Restricting the analysis to those target cortical regions which exhibited positive correlations with the specified seed regions, we observed a strikingly consistent pattern of results revealing that, in both hemispheres, the correlations associated with primary visual, primary auditory, primary somatosensory and primary olfactory cortex were invariably lower in the autistic compared to the non-autistic group. In contrast, seed masks placed in the left or right thalamus identified higher overall thalamocortical correlations in the autistic group.
Conclusions: The observed pattern of atypical interregional resting state correlations in autism spanned all sensory systems examined, consistent with the domain-independent character of previously documented perceptual differences. The regional pattern and reliability of our results suggests that reduced cortico-cortical and increased thalamocortical resting state correlations in the systems involved in early sensory processing could be a useful physiological marker for atypical function in autistic perceptual systems.