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Regional Differences in Gray Matter Structure in Children with Autism Spectrum Disorder

Thursday, 2 May 2013: 14:00-18:00
Banquet Hall (Kursaal Centre)
N. E. Foster1,2, K. A. R. Doyle-Thomas3, A. Tryfon1,2, T. Ouimet1,2, A. C. Evans2, E. Anagnostou3, L. Zwaigenbaum4, K. L. Hyde1,2 and .. NeuroDevNet ASD Imaging Group5, (1)Faculty of Medicine, Montreal Children’s Hospital, McGill University, Montreal, QC, Canada, (2)Montreal Neurological Institute, Montreal, QC, Canada, (3)Holland Bloorview Kids Rehabilitation Hospital, Toronto, ON, Canada, (4)Glenrose Rehabilitation Hospital, University of Alberta, Edmonton, AB, Canada, (5), Vancouver, BC, Canada
Background: Structural brain imaging studies have revealed differences between individuals with autism spectrum disorders (ASD) and Typical Development (TD), particularly in frontal brain regions. However, there are few detailed studies of gray matter structural differences between ASD and TD children using multiple structural imaging techniques.

Objectives: To better document gray matter structural differences in ASD versus TD children using multiple structural brain imaging measures, including cortical thickness (CT), Voxel Based Morphometry (VBM) and Surface Area (SA). 

Methods: We present preliminary data from 30 ASD and 36 TD control children as part of the ‘NeuroDevNet ASD project’, an ongoing multi-site study on brain and behavioral development in ASD.  Ethical approval was granted by the Montreal Neurological Institute Research Ethics Board. The groups were matched on age (from 6-16 years old), and all subjects had an IQ above 70 (except 2 ASD individuals). CT, gray matter VBM, and SA data were generated from T1 structural MR images using the CIVET pipeline. The general linear model was used to test for group differences in CT, VBM and SA, covarying for age and scanner site.

Results: The CT group comparison revealed greater CT in ASD in left and right frontal regions including middle frontal gyrus and medial orbitofrontal gyrus.  The VBM analysis revealed increases in gray matter density in the same brain regions. Combined increases in CT and SA in ASD were found in fusiform gyrus. Increased SA was also found in left superior temporal gyrus, adjacent to primary auditory cortex.

Conclusions: We provide convergent evidence through multiple structural imaging techniques for regional differences in gray matter in ASD children.  Structural differences found in frontal and temporal cortex correspond to previous functional differences found in ASD in regions known to be involved in core features (e.g., atypical social cognition and communication), and atypical sensory perception in ASD.

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