Brain anatomy differences between autistic, typically developing individuals are indistinguishable

Posted on November 5, 2014

"Our findings offer definitive answers regarding several scientific controversies about brain anatomy, which have occupied autism research for the past 10 to 15 years," says Dr. Ilan Dinstein of BGU's Departments of Psychology and Brain and Cognitive Sciences. "Previous hypotheses suggesting that autism is associated with larger intra-cranial gray matter, white matter and amygdala volumes, or smaller cerebellar, corpus callosum and hippocampus volumes were mostly refuted by this new study."

The researchers used data from the Autism Brain Imaging Data Exchange (ABIDE), which provides an unprecedented opportunity to conduct large-scale comparisons of anatomical MRI scans across autism and control groups and resolve many outstanding questions. This recently- released database is a worldwide collection of MRI scans from over 1,000 individuals (half with autism and half controls) ages six to 35 years old.

In the study, the researchers performed very detailed anatomical examinations of the scans, which included dividing each brain into over 180 regions of interest and assessing multiple anatomical measures such as the volume, surface area and thickness of each region. The researchers then examined how the autism and control groups differed with respect to each region and also with respect to groups of regions using more complex analyses.

The most striking finding was that anatomical differences within both the control group and the autistic group was immense and greatly overshadowed minute differences between the two groups. For example, individuals in the control group differ by 80 to 90 percent in their brain volumes, while differences in brain volume across autism and control groups differed by two to three percent at most. This led to the conclusion that anatomical measures of brain volume or surface areas do not offer much information regarding the underlying mechanism or pathology of Autistic Spectrum Disorder (ASD).

These sobering results suggest that autism is not a disorder that is associated with specific anatomical pathology and as a result, anatomical measures alone are likely to be of low scientific and clinical significance for identifying children, adolescents and adults with ASD, or for elucidating their neuropathology.

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Source material from Science Daily