Approaches to local connectivity in autism using resting state functional connectivity MRI

While the literature on aberrant long-distance connectivity in autism spectrum disorder (ASD) has grown fast over the past decade, little is known about local connectivity. We used regional homogeneity and local density approaches at different spatial scales to examine local connectivity in 29 children and adolescents with ASD and 29 matched typically developing participants, using resting state functional magnetic resonance imaging data. Across a total of 12 anlysis pipelines the gross pattern of between-group findings was overall stable, with local overconnectivity in the ASD group in occipital and posterior tempporal regions and underconnectivity in middle/posterior cingulate, and medial prefrontal regions. This general patern was confirmed in secondary anlyses for low-mention subsamples (n= 20 per group), in which time series segments with >0.25 mm head motion were censored, as well as in an analysis including global signal regression. Local overconnectivity in visual regions appears in ASD, whereas cingulate and medial frontal underconnnectivity may relate to aberrant function within the defalut mode network.