Children with autism have more brain cells and heavier brains compared to typically developing children, according to researchers partly funded by the National Institutes of Health. Published in theJournal of the American Medical Association on Nov. 9, 2011, the small, preliminary study provides direct evidence for possible prenatal causes of autism.
"Earlier studies of head circumference and early brain overgrowth have pointed us in this direction, but there have been few quantitative neuroanatomical studies due to the lack of post-mortem tissue from children with autism," said Thomas R. Insel, M.D., director of the National Institute of Mental Health (NIMH), part of NIH. "These new results, along with an earlier study reporting altered wiring of the prefrontal cortex, focus our attention on this critical area of the brain in autism."
The prefrontal cortex is involved in various higher order functions such as language and communication, social behavior, mood, and attention. Children who have autism tend to show deficits in such functions.
The researchers found that children with autism had 67 percent more neurons in the prefrontal cortex and heavier brains for their age compared to typically developing children. Since these neurons are produced before birth, the study's findings suggest that faulty prenatal cell birth or maintenance may be involved in the development of autism. Another possible factor that may contribute to the neuronal excess is a reduction in apoptosis, or programmed cell death, which normally occurs during the third trimester and early postnatal life.
Read more: http://www.sciencedaily.com/releases/2011/11/111108200720
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