31262
Typical and Anomalous Inferior Parietal Lobule Connectivity in Children with Autism: Associations with Motor and Social-Communicative Skills.
Children with autism spectrum disorder (ASD) consistently display impairments in skilled motor behavior, of which, there is strong correspondence with primary social and communicative features of autism. In particular, children with ASD show impairment in the representation of everyday actions (praxis) as measured using pantomimed gestures. Healthy and impaired brain states have reliably shown that connectivity of the inferior parietal lobe (IPL) is essential for the representation of everyday motor skills. Despite robust behavioral evidence of abnormal praxis in ASD, there is little understanding of how IPL connectivity affects praxis in children with ASD.
Objectives:
To test if connectivity of specific IPL subnetworks is abnormal in children with ASD, if IPL connectivity is related to praxis, and if connectivity meaningful to praxis is also related to core social and communicative features in children with ASD.
Methods:
We acquired resting-state functional magnetic resonance imaging (rfMRI) scans from 128 (63 ASD, 65 typically developing, TD) children aged 8-12 years. Groups were balanced for age, handedness, and IQ general ability index (GAI). Masked independent components analysis (ICA) and dual regression were used to estimate functional connectivity of the IPL, separately for left and right hemisphere. We tested for brain-behavior relationships by including measures of praxis-based gesture (Florida Apraxia Battery modified for children) and social skill (social responsiveness scale, SRS total raw score) as covariates. Reported results meet FWE cluster correction (P<0.05), with initial threshold post-correction for multiple tests at P<0.005.
Results:
Children with ASD were less accurate on praxis gesture than TD children (P<0.0001). Multiple IPL subnetworks were correlated with praxis, with strongest associations for the left and right central IPL subnetworks (cIPL: posterior supramarginal and anterior angular gyri). For both ASD and TD, greater accuracy on praxis gestures was related to increased connectivity from cIPL to predominantly left primary and secondary premotor cortices, bilateral posterior parietal cortex, and cerebellum (Figure1). Further, we observed ASD-specific praxis effects, particularly right cIPL connectivity with left angular gyrus, primary visual cortex, and right cerebellum (Figure2a). In addition, for children with ASD, SRS was correlated with praxis-related connectivity between right cIPL subnetwork and left angular gyrus, left cerebellum, and bilateral retrosplenial cortex (Figure2b).
Conclusions:
Our findings suggest that the representation of everyday motor skill, or praxis, in children (TD and ASD) relies on cIPL connectivity (predominantly left hemisphere). As such, impaired praxis in children with ASD appears to be associated with reduced connectivity of this cIPL subnetwork. Further, our observation of ASD-specific associations of stronger right cIPL connectivity with better praxis and SRS scores, suggests that for children with ASD, connectivity of the right cIPL may have compensatory influence on development of a wide range of skills – including motor and social-communicative skills. These findings highlight the importance in understanding the involvement of the IPL connectivity in impaired acquisition of skilled behavior in ASD with potential utility for development of movement-based intervention to augment social and communicative skills.