Size of a specific part of the brain helps experts pinpoint when autism develops

The size of a particular area of the brain could help experts determine when autism could first formulate, University of North Carolina researchers report.

As noted in the May issue of Archives of General Psychiatry, the findings compared the MRI results of 50 autistic children and 33 control children.

The UNC scientists centered on the amygdala, a region deep in the brain that helps control emotions, regulate attention and read social cues from eye contact.

The amygdala is a structure that has previously been implicated in social and emotional perception and in autism, said Dr. Joseph Piven, director of UNC’s Neurodevelopmental Disorders Research Center and one of the study’s authors.

“We also found that this enlargement was related to something called joint attention, or the ability of a young child to take cues from an adult about where to look in the visual field, for example, at an object of interest,” he said.

This ability occurs in a narrow window, between 9 and 15 months, and is believed to be a significant deficit in autistic individuals that predicts poor outcomes in social behavior and language, Piven explained.

“In another study, we have shown evidence that the brain in autism is normal in size until the end of the first year of life, at which time it overgrows,” he said.

Because boys were most of their sample, they added that further studies are necessary in autistic girls.
The scientists also stated that the severity of autism was less in children whose amygdala were largest.