Autism Associated with Abnormal Brain Structure

Kathleen Blanchard's picture
Autism and Brain

According to a report published in the May issues of the Archives of General Psychiatry, autism is associated with abnormal brain structure. Researchers have found the area of the brain responsible for processing information related to emotions, and attention, the amygdala, is enlarged in toddlers with autism. Enlarged of the amygdala, seen early in life, may be the root cause of why autistic toddlers are unable to share attention with others. Abnormal brain structure is an important component associated with autism.

Matthew W. Mosconi, Ph.D., and colleagues at the University of North Carolina at Chapel Hill performed MRI studies on 50 autistic children at age 2 and 4. The researchers also looked at the behavior of the autistic children, finding they were more likely to have abnormal brain structure, specifically enlargement of the amygdala. The scientists compared the children to a control group.


The authors write, "These findings suggest that, consistent with a previous report of head circumference growth rates in autism and studies of amygdala volume in childhood, amygdala growth trajectories are accelerated before age 2 years in autism and remain enlarged during early childhood, “ leading the group to believe abnormal brain structure is a major factor in autism.

The study concluded that abnormal brain structure, early in life, plays a critical role in recognizing facial expression and processing significant emotional events. The researchers say, "Moreover, amygdala enlargement in 2-year-old children with autism is disproportionate to overall brain enlargement and remains disproportionate at age 4 years."

It is likely that autism is associated with multiple areas of brain abnormality. The new study shows that autism may be closely associated with abnormal brain structure, specifically related to enlargement of the amygdala of the brain.

Arch Gen Psychiatry. 2009;66(5):509-516.