Autistic Brain Structure Is Different

Feb. 14, 2002 -- The social isolation and seemingly obsessive-compulsive behavior typically associated with autism may trace its roots back to structural problems in the brain, according to a new study.

Using computerized imaging, researchers have now identified among autistic patients abnormalities in the areas of the brain that control speech and the senses. The study, published in the February 2002 issue of the journal Neurology, suggests that these structural differences may explain many classic autistic behaviors, such as social withdrawal, resistance to change, and odd speech patterns.

Researchers studied and compared the brain tissue of nine autistic and nine healthy patients. They found basic differences between the groups in the size and number of structures called minicolumns. Minicolumns are basic organizational units of brain cells. They act as connective wiring, allowing a person to take in information, process it, and respond. Autistic patients had smaller minicolumns, but also many more of them compared with healthy individuals.

The study authors suggest that if autistic brains have more minicolumns, but not the necessary processing capacity required to interpret and make sense of all that information, then the brain becomes flooded by "noise" -- incoming signals that put too much strain on the brain.

These findings are consistent with the current theory stating that autistic individuals are in a constant state of arousal -- since they are being bombarded by signals that their brain cannot process. As a result, they may use abnormal behaviors as a coping mechanism to silence the noise in their brain.

Researchers say more studies are needed to find out whether a genetic mutation or some other factor may be responsible for this brain abnormality.