Altered hierarchical rank in intrinsic neural time-scales in autism spectrum disorder

Autism spectrum disorder (ASD) is a developmental difference that affects millions worldwide. Resting-state functional magnetic resonance imaging (rs-fMRI) is an imaging technique that has recently been used to study the neurophysiology of autism and its heterogeneity. In contrast to functional connectivity network, the intrinsic neural timescale (INT) is a newly developed metric from rs-fMRI, which quantifies the duration of neural information is retained within cortical circuits throughout the brain. The variability in the INT values determines the functional hierarchy of the brain and reflects the excitation/inhibition (E/I) balance of circuit dynamics, which is crucial for understanding the deficiency in cognitive functions in ASD. In this study, we explored hierarchical gradient differences in ASD and typically developing controls (TDC). We used rs-fMRI data of 81 individuals. The subjects in our cohort were further categorized by their scan location and age range (13-18) into four groups: 29 males with ASD, 6 females with ASD, 36 males with TDC, and 10 females with TDC. Linear mixed effect model and pairwise comparison were implemented to investigate the large-scale hierarchical organization and local differences. Among the 186 cortical and 82 subcortical ROI’s analyzed we observed a statistical significance in hierarchical rank amongst individuals with ASD. We further analyzed specific brain regions that had significant differences in INT value between ASD and TDC groups.