The Medical Research Council UK Autism Imaging Multicentre Study which was comprised of the Institute of Psychiatry at Kings College in London, the Autism Research Centre at the University of Cambridge and the Autism Research Group at the University of Oxford analyzed the brains of males with autism versus male controls using quantitative magnetic resonance imaging. The study was comprised of 89 men with autism spectrum disorder (mean age 26 and “full-scale IQ 110”) and 89 “male control participants” (mean age 28 and “full-scale IQ 113”). The differences in the two groups were identified statistically through “partial least squares analysis.”
The results of the study showed significant brain anatomy differences between the two groups although the adults with autism spectrum disorder did not “differ significantly from the controls in overall brain volume.” Study individuals with autism did have “significantly increased gray matter volume in the anterior temporal and dorsolateral prefrontal regions and significant reductions in the occipital and medial parietal regions as compared with controls.” The importance of these regional differences in neuroanatomy is that there was a “significant correlation between these differences and the severity of specific autistic symptoms.” Additional differences between those with autism spectrum disorder and the male controls were that those with autism had “spatially distributed reductions in white matter volume.”
In summary, quantitative MRI showed that although the overall brain volume of those with autism spectrum disorder and the controls (commonly referred to as the neurotypical) is not significantly different, there are significant brain anatomy differences in gray matter volume as well as white matter volume in those with autism spectrum disorder compared to the neurotypical; and further, the regional differences correlated with autistic symptom severity.
Source: Journal of the Archives of General Psychiatry; Jan. 2, 2012; copyrighted by the American Medical Association as detailed on the Nuffield Department of Clinical Neurosciences Medical Sciences Division of University of Oxford website: http://www.ndcn.ox.ac.uk/publications/343223.