Atypical sulcal anatomy in young children with autism spectrum disorder

Abstract

Autism spectrum disorder is associated with an altered early brain development. However, the specific cortical structure abnormalities underlying this disorder remain largely unknown. Nonetheless, atypical cortical folding provides lingering evidence of early disruptions in neurodevelopmental processes and identifying changes in the geometry of cortical sulci is of primary interest for characterizing these structural abnormalities in autism and their evolution over the first stages of brain development. Here, we applied state-of-the-art sulcus-based morphometry methods to a large highly-selective cohort of 73 young male children of age spanning from 18 to 108 months. Moreover, such large cohort was selected through extensive behavioral assessments and stringent inclusion criteria for the group of 59 children with autism. After manual labeling of 59 different sulci in each hemisphere, we computed multiple shape descriptors for each single sulcus element, hereby separating the folding measurement into distinct factors such as the length and depth of the sulcus. We demonstrated that the central, intraparietal and frontal medial sulci showed a significant and consistent pattern of abnormalities across our different geometrical indices. We also found that autistic and control children exhibited strikingly different relationships between age and structural changes in brain morphology. Lastly, the different measures of sulcus shapes were correlated with the CARS and ADOS scores that are specific to the autistic pathology and indices of symptom severity. Inherently, these structural abnormalities are confined to regions that are functionally relevant with respect to cognitive disorders in ASD. In contrast to those previously reported in adults, it is very unlikely that these abnormalities originate from general compensatory mechanisms unrelated to the primary pathology. Rather, they most probably reflect an early disruption on developmental trajectory that could be part of the primary pathology.

A systematic review of structural MRI biomarkers in autism spectrum disorder: A machine learning perspective

“…Of the two reviewed studies quantifying sulcal morphology, specifically sulcal depth (SD), one reported altered SD in children with autism (Dierker et al, 2015) and the other reported no changes in SD (Pappaianni et al, 2018). Despite increased SD (Ecker et al, 2010a; Nordahl et al, 2007), sulcal length (Shokouhi et al, 2012) and sulcal depth and length combined (Auzias et al, 2014) being observed in patients with ASD in several 1.5 T MRI studies, specifically in frontal and parietal regions, as well as sulcal morphology being correlating with several measures of severity including CARS and ADOS (Auzias et al, 2014; Watanabe et al, 2014), there is limited evidence to establish a specific measure of sulcal morphology as a biomarker of autism. Further studies are needed utilising 3 T imaging and leveraging the multiple surface maps (such as those produced by FreeSurfer) to elucidate any cortical differences associated with autism.…”

Reduced Gyrification Is Related to Reduced Interhemispheric Connectivity in Autism Spectrum Disorders

“…Whole-brain studies have indeed shown a pattern of increased sulcal complexity 13 and differences in cortical shape 14 and sulcal pattern 15,16 in children and adolescents with ASD.…”

Genetic analysis of cortical sulci in 1,009 adults

“…However, there are many more features besides volume that can be reliably extracted from brain scans, and these may offer additional insights into the specific genetic programs that help shape the human brain. "Sulcus-based morphometry" provides measures of the cortical fissures of the brain, that have been found to be associated with developmental maturation in adolescents [2], degenerative changes in the elderly [3], schizophrenia [4,5], bipolar disorders [6] and autism in children [7]; altered fissuration is also found in several neurogenetic disorders, such as Williams syndrome [8,9].…”