Megan Brooks
Mar 08, 2013

Three-dimensional mapping of the brains of 7 adults with a rare brain birth defect has shed new light on the cause of autism.
Known as agenesis of the corpus callosum (AgCC), the defect is characterized by complete or partial absence of the corpus callosum, which connects the left and right sides of the brain. One of the primary genetic causes of autism, it was part of the brain physiology of Laurence Kim Peek, the savant portrayed by actor Dustin Hoffman in the 1987 film Rain Man.
"Our most interesting observation was the reduced connectivity of the cingulate gyrus in both left and right cerebral hemispheres in AgCC compared to the normally developed brain," Pratik Mukherjee, MD, PhD, professor of radiology and biomedical imaging at the University of California, San Francisco (UCSF), and senior coauthor of the research, told Medscape Medical News.
"This is interesting for 2 reasons — it definitively shows that abnormalities in AgCC are not limited to the corpus callosum; and it helps explain the high incidence of autistic spectrum disorder in individuals with AgCC," said Dr. Mukherjee.
"The cingulate gyrus is perhaps the most important structure in the brain for integrating cognitive information with emotional signals. It has already been shown that the cingulate gyrus is abnormal in autism," he added.
The study will be published in the April 15 issue of NeuroImage and is available online now.