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Nov. 29, 2007 (Chicago) -- Using a novel imaging technique, researchers have found that autistic kids have more gray matter in the brain area that governs social processing and learning-by-seeing than children who don't have the developmental disorder.
Basically, the "monkey see, monkey do" feature is broken in autistic youngsters, according to researcher Manzar Ashtari, PhD, of the Children's Hospital of Philadelphia.
First observed in the macaque monkey, this is the brain system that governs our ability to empathize and learn by watching another person.
Ashtari studied mirror neurons -- brain cells that activate when you perform an action or experience an emotion and when you see someone else doing the same thing.
"Our findings suggest that an inability of the autistic child to relate to people and life situations in an ordinary way is the result of an abnormally functioning mirror neuron system," she says.
The study, presented at the annual meeting of the Radiological Society of North America, involved 13 high-functioning boys with autism or Asperger syndrome (an autism spectrum disorder) and an IQ greater than 70 and 12 healthy boys. Their average age was 11.
Brain function was assessed using a combination of two techniques: diffusion tensor imaging (DTI) and apparent diffusion coefficient based morphometry (ABM).
Results showed that the autistic children had increased gray matter in brain regions of the parietal lobes that control our sense of environment.
The children then underwent tests that assess learning and behavior.
"The larger the gray matter in the parietal lobes, the more restricted and the more stereotyped the behavior of the child," Ashtari tells WebMD.
Also, in the healthy children, the larger the gray matter in the parietal area, the higher the IQ, she says.
"But in the autistic brain, increased gray matter does not correspond to IQ, because this gray matter is not functioning properly," she says.
"If you think of autism as an inability to see other individuals as creatures like yourself, then mirror neurons would be a logical thing to investigate," says Robert Zimmerman, MD, executive chairman of the department of radiology at New York Presbyterian-Weill Cornell Medical School of Medicine in New York City.
Zimmerman tells WebMD the research "is promising in that it may offer a foothold into something we can actually measure to identify children with autism earlier. That's important so we can intervene earlier."
But there's still a long way to go before this will offer a tool to diagnose autism, cautions Philip O. Alderson, MD, chairman of radiation oncology at Columbia University in New York.
Ashtari conducted the study while at the Fay J. Lindner Center for Autism in North Shore-Long Island Jewish Health System in Bethpage, N.Y.