Autism Linked To Enlarged Portion Of Brain

May 5, 2009 7:07 a.m. EST

Chapel Hill, NC (AHN) - A new brain imaging study suggests that toddlers with autism are more likely to have an enlarged portion of the brain associated with functions like the processing of faces and emotions.

The researchers, with the University of North Carolina, Chapel Hill, also said that this enlargement of the amygdala, appears to be associated with the ability to share attention with others, which is a function thought by many experts to be a predictor of later social and language function in children with autism.

The study was published in the May issue of the Archives of General Psychiatry.

The researchers said that the onset of the disorder likely occurs during the first year of life.

Matthew Mosconi and his colleagues at UNC conducted a magnetic resonance imaging study involving 50 children with autism and 33 control children. The participants underwent brain scans along with testing of certain behavioral features of autism at ages 2 and 4.

Mosconi said in a Journal of the American Medical Association press release that the autistic participants were more likely to have enlarged amygdalas by ages 2 and 4 than the control participants.

"The amygdala plays a critical role in early-stage processing of facial expression and in alerting cortical areas to the emotional significance of an event," the authors wrote. "Amygdala disturbances early in development, therefore, disrupt the appropriate assignment of emotional significance to faces and social interaction."