Researchers found a reduced connection between the amygdala and parts of the brain associated with social communication and language in children with autism spectrum disorder (ASD). The study was published in the Journal of the American Academy of Child and Adolescent Psychiatry.

According to lead researcher, Christine Nordahl, assistant adjunct professor of psychiatry and behavioral sciences at the University of California, Davis, these conclusions were difficult to reach because brains they examined could be affected by intervention, medication, life in general or the neural basis of autism. 

To get a better insight, researchers used imaging and scanned the amygdala of 43 children with autism and 29 controls between the ages of 2 and 4. Because it wasn't easy to keep most of the children still in the scanner, Nordahl and her colleagues waited until they fell asleep and then carefully placed the children into the MRI machine and scanned them as they slept. 

Data suggested that the preschool aged children with ASD have an interrupted functional connectivity between the amygdala and parts of their brain key to social communication and language. Connectivity that was weaker was also associated with increased autism severity. 

"Moverover, although amygdala connectivity was associated with behavioral domains that are diagnostic of ASD, altered connectivity of primary visual cortex was related to sensory hypersensitivity," the authors wrote. 

To better understand how growth in these same participants affect connectivity, Nordahl and her team will scan the same participants over time.