A psychology researcher has pinpointed regions of the brain that are linked to "ritualistic repetitive behavior" in autistic children -- the insatiable desire to rock back and forth for hours or to tirelessly march in place.
Keith Shafritz, an assistant professor of psychology at Hofstra University on Long Island, compared brain images of autistic children with those of neurologically normal youngsters. He and collaborators at Duke University and the University of North Carolina in Chapel Hill used a form of magnetic resonance imaging to explore sites in the brain.
They reported their findings in the current issue of Biological Psychiatry.
Repetitive behavior is one of autism's core traits. It has driven parents to extremes as they try to distract a child to engage in other activities.
Mapping the brain constitutes a journey into the inner labyrinths of a three-pound cosmos where countless frontiers have yet to be explored.
In children with autism, Shafritz found deficits in specific regions of the cerebral cortex, the outer layer of gray matter linked to all higher human functions, including repetitive behavior. He also mapped deficits in the basal ganglia, a region deep below the cerebral hemispheres.
"We like to think about the research process as discovering clues why people engage in certain behaviors," Shafritz said. "We were able to identify a series of brain regions that showed diminished activity when people were asked to alter certain behaviors and were not able to do so."
Autism is a neurodevelopmental disorder that is becoming a major public policy issue. Federal health officials estimate that it afflicts 1 in every 150 children, which affects not only families but communities.
School systems don't have enough appropriately trained teachers. Social services departments are overwhelmed by parents who need support and respite care.
For clues to the disorder, some scientists are scanning the human genome for suspect DNA.
Others, like Shafritz, are exploring the geography of the brain.
Edward G. Carr, a psychology professor at Stony Brook University in New York, said Shafritz's discovery was important because it helped demystify repetitive behavior.
"Repetitive behavior is sometimes called self-stimulatory behavior. A very common form of it is body-rocking. A child will do it for hours," Carr said. "Another child may wave his or her hands back and forth in front of their eyes. This is very common, and it's called hand-flapping. They extend their arms forward and wave their hands in front of them. It's like a light show."
Shafritz said the brain areas associated with repetitious behavior were not associated with another autism problem, self-injury. Some children repeatedly slam their heads against a wall, for instance.
Still, Shafritz found a relationship between the newly identified brain areas and overlapping regions linked to schizophrenia, obsessive compulsive disorder and attention-deficit hyperactivity disorder.
Dr. Anil K. Malhotra, director of psychiatric research at Zucker Hillside Hospital in Glen Oaks, N.Y., said he was not surprised. He too is studying links between autism and schizophrenia, and autism and obsessive-compulsive disorder.