In resting state functional magnetic resonance imaging (fMRI) studies of autism spectrum

disorders (ASDs) decreased frontal-posterior functional connectivity is a persistent finding.

However, the picture of the default mode network (DMN) hypoconnectivity remains

incomplete. In addition, the functional connectivity analyses have been shown to be

susceptible even to subtle motion. DMN hypoconnectivity in ASD has been specifically

called for re-evaluation with stringent motion correction, which we aimed to conduct by

so-called scrubbing. A rich set of default mode subnetworks can be obtained with high

dimensional group independent component analysis (ICA) which can potentially provide

more detailed view of the connectivity alterations. We compared the DMN connectivity

in high-functioning adolescents with ASDs to typically developing controls using ICA

dual-regression with decompositions from typical to high dimensionality. Dual-regression

analysis within DMN subnetworks did not reveal alterations but connectivity between

anterior and posterior DMN subnetworks was decreased in ASD. The results were very

similar with and without motion scrubbing thus indicating the efficacy of the conventional

motion correction methods combined with ICA dual-regression. Specific dissociation

between DMN subnetworks was revealed on high ICA dimensionality, where networks

centered at the medial prefrontal cortex and retrosplenial cortex showed weakened

coupling in adolescents with ASDs compared to typically developing control participants.

Generally the results speak for disruption in the anterior-posterior DMN interplay on the

network level whereas local functional connectivity in DMN seems relatively unaltered.