White matter correlates of sensory processing in autism spectrum disorders

Abstract

Autism spectrum disorder (ASD) has been characterized by atypical socio-communicative behavior, sensorimotor impairment and abnormal neurodevelopmental trajectories. DTI has been used to determine the presence and nature of abnormality in white matter integrity that may contribute to the behavioral phenomena that characterize ASD. Although atypical patterns of sensory responding in ASD are well documented in the behavioral literature, much less is known about the neural networks associated with aberrant sensory processing. To address the roles of basic sensory, sensory association and early attentional processes in sensory responsiveness in ASD, our investigation focused on five white matter fiber tracts known to be involved in these various stages of sensory processing: superior corona radiata, centrum semiovale, inferior longitudinal fasciculus, posterior limb of the internal capsule, and splenium. We acquired high angular resolution diffusion images from 32 children with ASD and 26 typically developing children between the ages of 5 and 8. We also administered sensory assessments to examine brain-behavior relationships between white matter integrity and sensory variables. Our findings suggest a modulatory role of the inferior longitudinal fasciculus and splenium in atypical sensorimotor and early attention processes in ASD. Increased tactile defensiveness was found to be related to reduced fractional anisotropy in the inferior longitudinal fasciculus, which may reflect an aberrant connection between limbic structures in the temporal lobe and the inferior parietal cortex. Our findings also corroborate the modulatory role of the splenium in attentional orienting, but suggest the possibility of a more diffuse or separable network for social orienting in ASD. Future investigation should consider the use of whole brain analyses for a more robust assessment of white matter microstructure.

Somatosensory Event-Related Potentials and Association with Tactile Behavioral Responsiveness Patterns in Children with ASD

“…This supports the idea that both sensory hypo- and hyper-responsiveness are important contributors to the global autism behavioral phenotype. More specifically, this study provides further support of a link between atypical response to touch and autism symptoms (Cascio, Foss-Feig, Burnette, Heacock, & Cosby, 2012; Foss-Feig et al, 2012; Pryweller et al, 2014; Voos, Pelphrey, & Kaiser, 2013), suggesting that this is an area ripe for further exploration in ASD.…”

Thalamocortical Dysconnectivity in Autism Spectrum Disorder: An Analysis of the Autism Brain Imaging Data Exchange

“…The serotonergic system likely has multiple functional influences on the development and expression of sensory and other behavioral features of ASD, including the influence of transient perinatal expression of serotonin transporter on the organization of thalamocortical somatotopic projections to primary somatosensory cortex (44,45). While tactile defensiveness in ASD has also been associated with structural connectivity differences in intracortical association fibers (46), a model of cascading effects downstream from aberrantly enhanced thalamocortical signals to somatosensory cortex is very plausible. Such a model could, if supported by future studies designed to test it explicitly, unify behavioral measures as well as brain structural and functional correlates of aberrant somatosensory perception in ASD.…”

Intrainsular connectivity and somatosensory responsiveness in young children with ASD

“…This sample is the same as that reported by Pryweller et al [12]. After excluding participants with poor image quality resulting from excessive motion or scanner/acquisition errors (ASD n  = 5; TD n  = 1), the final sample included 23 children with ASD (6.61 years ± 0.89, 2 females) and 24 children with TD (6.58 years ± 1.13, 4 females).…”