Precentral gyrus functional connectivity signatures of autism.

Mary Beth Nebel,Anita D Barber,Ani Eloyan,Stewart H Mostofsky

doi:10.3389/fnsys.2014.00080

Abstract

Motor impairments are prevalent in children with autism spectrum disorders (ASD) and are perhaps the earliest symptoms to develop. In addition, motor skills relate to the communicative/social deficits at the core of ASD diagnosis, and these behavioral deficits may reflect abnormal connectivity within brain networks underlying motor control and learning. Despite the fact that motor abnormalities in ASD are well-characterized, there remains a fundamental disconnect between the complexity of the clinical presentation of ASD and the underlying neurobiological mechanisms. In this study, we examined connectivity within and between functional subregions of a key component of the motor control network, the precentral gyrus, using resting state functional Magnetic Resonance Imaging data collected from a large, heterogeneous sample of individuals with ASD as well as neurotypical controls. We found that the strength of connectivity within and between distinct functional subregions of the precentral gyrus was related to ASD diagnosis and to the severity of ASD traits. In particular, connectivity involving the dorsomedial (lower limb/trunk) subregion was abnormal in ASD individuals as predicted by models using a dichotomous variable coding for the presence of ASD, as well as models using symptom severity ratings. These findings provide further support for a link between motor and social/communicative abilities in ASD.

Highlights

Defined by impairments in social reciprocity and communication, as well as the presence of restricted, repetitive behaviors, Autism Spectrum Disorder (ASD) is a pervasive diagnosis that emerges early in life and is generally associated with life-long disability (Howlin et al, 2004)
Consistent with our hypothesis, stronger functional coupling between the DM and VL parcels was associated with increased odds of ASD (e β = 2.37, p = 0.036), indicating that individuals with ASD showed increased DM-VL coupling compared to controls
Functional connectivity differences involving the DM and Anterior Lateral (AL) regions and the rest of the brain outside of the precentral gyrus (PCG) have previously been reported in children with ASD (Nebel et al, 2014); these findings suggest that the way DM and AL are connected to the other functional subregions within the PCG is disrupted in individuals with ASD

Summary

Introduction

Defined by impairments in social reciprocity and communication, as well as the presence of restricted, repetitive behaviors, Autism Spectrum Disorder (ASD) is a pervasive diagnosis that emerges early in life and is generally associated with life-long disability (Howlin et al, 2004). The severity of motor impairments experienced by children with ASD relates to the severity of the communicative/social deficits at the core of their diagnosis (Dziuk et al, 2007; Dowell et al, 2009), and better early motor control has been shown to be related to decreased severity of ASD in later life (Sutera et al, 2007). Considered together, these converging lines of evidence suggest that a purely cognitive explanation for ASD is shortsighted and underscore the need for systematic examination of the neural underpinnings of motor development in individuals with ASD

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Conclusion