Altered global modular organization of intrinsic functional connectivity in autism arises from atypical node‐level processing.

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by restricted interests and repetitive behaviors as well as social‐communication deficits. These traits are associated with atypicality of functional brain networks. Modular organization in the brain plays a crucial role in network stability and adaptability for neurodevelopment. Previous neuroimaging research demonstrates discrepancies in studies of functional brain modular organization in ASD. These discrepancies result from the examination of mixed age groups. Furthermore, recent findings suggest that while much attention has been given to deriving atlases and measuring the connections between nodes, within node information may also be crucial in determining altered modular organization in ASD compared with typical development (TD). However, altered modular organization originating from systematic nodal changes are yet to be explored in younger children with ASD. Here, we used graph‐theoretical measures to fill this knowledge gap. To this end, we utilized multicenter resting‐state fMRI data collected from 5 to 10‐year‐old children—34 ASD and 40 TD obtained from the Autism Brain Image Data Exchange (ABIDE) I and II. We demonstrate that alterations in topological roles and modular cohesiveness are the two key properties of brain regions anchored in default mode, sensorimotor, and salience networks, and primarily relate to social and sensory deficits in children with ASD. These results demonstrate that atypical global network organization in children with ASD arises from nodal role changes, and contribute to the growing body of literature suggesting that there is interesting information within nodes providing critical markers of functional brain networks in autistic children. Lay Summary: Modular organization in the brain plays a crucial role in network stability and adaptability for neurodevelopment. Altered global modularity demonstrates discrepancies in prior studies of functional brain modular organization in autism spectrum disorder (ASD). These discrepancies result from the examination of mixed age groups. In the present study, we examined how such discrepancies and altered global modular organization in ASD originates from atypicality at the systematic nodal level, focusing on children with ASD. We demonstrate that many of the previous discrepancies of altered functional connectivity in ASD could be reconciled based on nodal role identification and functional cartography of nodes. Our findings suggest that alterations in nodal topology may start occurring at early ages in children with ASD. [ABSTRACT FROM AUTHOR]