This brain structure may grow too fast in babies who develop autism
A brain structure called the amygdala grows too fast in babies who are diagnosed with autism by age 2, a new study suggests.
The study researchers found that this overgrowth occurs between 6 and 12 months of age, before children are typically diagnosed with autism. The findings, published Friday (March 25) in The American Journal of Psychiatry, suggest that therapies for children at high risk of autism may have the best chance of working if they start in infancy.
"Our research suggests an optimal time to start interventions and support children who are at highest likelihood of developing autism may be during the first year of life," study senior author Dr. Joseph Piven ... said in a statement. ...
The amygdala is an almond-shaped structure deep in the brain that's involved with processing emotions, including feelings of fear, as well as interpreting facial expressions. Researchers already knew that the amygdala appears larger in school-age children with ASD compared with children without ASD, but exactly when this enlargement starts was not known. ...
In the new study, researchers scanned the brains of more than 400 infants, including 270 who were at higher risk of developing autism because they had an older sibling with the condition; 109 infants with typical development; and 29 infants with Fragile X syndrome, a genetic disorder that causes developmental and intellectual disability. The children underwent MRI scans at ages 6 months, 12 months and 24 months. By age 24 months, 58 (or about 21%) of the at-risk children had been diagnosed with ASD.
The researchers found that at age 6 months, all of the children had similar-sized amygdalae. But by 12 months, the children who would later develop autism had enlarged amygdalae compared with children who didn't develop autism and those with Fragile X syndrome. What's more, those with the fastest rate of amygdala growth had the most severe symptoms of autism. ...
The researchers hypothesized that early problems with visual and sensory information processing in infancy may put stress on the amygdala, resulting in its overgrowth.