Sulcation in children with autism spectrum disorders

Abstract

Background The neurobiology of autism remains poorly understood. Brain sulcation is a promising proxy to assess the cortical developmental trajectory in autism spectrum disorders. We aimed to explore this neurodevelopmental marker in children with autism and its association with symptoms in a large multicentric dataset. Methods 841 children with autism spectrum disorders (ASD), including 145 females, and 872 controls, including 251 females, underwent a high-resolution T1-weighted brain MRI. We processed images with the Brain VISA automatized pipeline to extract the local sulcal indices (l-SI) (the proportion of buried cortex) from 12 a priori determined brain regions for each hemisphere, covering the whole brain. We studied how the variations in regional sulcation were associated with clinical autism assessment scales (ADOS, ADI, SRS, RME), controlling for age and sex. Results Between children with ASD and controls, we found a significantly higher sulcation (l-SI) in control children compared with children with ASD in the left (p = 0.015) and right (p = 0.048) precentral regions. Within ASD children, a significant positive association was found between ADOS scores and sulcation in the right intra-parietal fissure (p = 0.049). Significant positive correlations were also found between ADI communication scores and sulcation in the left parietal region (p = 0.037), in the right medial frontal region (p = 0.035) and in the left posterior medial region (p = 0.049). Finally, significant correlations were found between l-SI and RME scores in right parietal (p = 0.037), right calcarine (p = 0.049) (positive) and left precentral regions (p = 0.014) (negative). Of note, most results were driven by girls. Limitations: p-values were not corrected for multiple comparisons. Sample size is reduced for girls’ analyses. Conclusions Our results suggest that clinical features of ASD are correlated with localized changes in cortical folding in children, mainly driven by girls. Increased symptomatic levels were associated with an increased right and decreased left sulcation, consistent with the decreased asymmetry theory of ASD. The study of cortical sulcation appears to be a promising marker of neurodevelopmental processes and their clinical correlates in ASD.