Altered Functional Connectivity of Unimodal Sensory and Multisensory Integration Networks Is Related to Symptom Severity in Autism Spectrum Disorder.

Background: Atypical sensory processing is a prevalent feature of autism spectrum disorder (ASD) and constitutes a core diagnostic criterion in DSM-5. However, the neurocognitive underpinnings of atypical unimodal and multimodal sensory processing and their relationships with autism symptoms remain unclear.

Methods: In this study, we examined intrinsic functional connectivity (FC) patterns among 5 unimodal sensory and multisensory integration (MSI) networks in ASD using a large multisite dataset (N = 646) and investigated the relationships between altered FC, atypical sensory processing, social communicative deficits, and overall autism symptoms using correlation and mediation analyses.

Results: Compared with typically developing control participants, participants in the ASD group demonstrated increased FC of the olfactory network, decreased FC within the MSI network, and decreased FC of the MSI-unimodal sensory networks. Furthermore, altered FC was positively associated with autism symptom severity, and such associations were completely mediated by atypical sensory processing and social communicative deficits.

Conclusions: ASD-specific olfactory overconnectivity and MSI-unimodal sensory underconnectivity lend support to the intense world theory and weak central coherence theory, suggesting olfactory hypersensitivity at the expense of MSI as a potential neural mechanism underlying atypical sensory processing in ASD. These atypical FC patterns suggest potential targets for psychological and neuromodulatory interventions.