Brain Region Linked to Rocking Motion in Autism

A New York researcher has pinpointed for the first time brain regions in children with autism linked to “ritualistic repetitive behavior,” the insatiable desire to rock back and forth for hours or tirelessly march in place.

Collaborating with investigators at Duke University and the University of North Carolina in Chapel Hill, Dr. Keith Shafritz, an assistant professor of psychology at Hofstra University, unmasked brain regions in children with autism typified by reduced neural activity. In a series of high-tech mapping studies, he compared brain images of children with autism to those of neurologically normal youngsters.

Repetitive behavior is one of autism’s core traits and has driven some parents to extremes as they try to distract a child to engage in other activities.

Shafritz and colleagues used a form of magnetic resonance imaging _ MRI _ to explore sites in the brain. They report their findings in the current issue of Biological Psychiatry.

Mapping the brain constitutes a journey into the inner labyrinths of a 3-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 last week. “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 rapidly becoming a major public policy issue. Federal health officials estimate it affects 1 in every 150 children, impacting not only individual families but communities. School systems lack a sufficient number of appropriately trained teachers; social services departments are overwhelmed by parents in need of support and respite care.

Amid social concerns are the plodding attempts to understand the disorder’s basic biology. Some scientists are scanning the human genome in search of suspect DNA. Others like Shafritz, are exploring the geography of the brain.

Edward Carr, a psychology professor at Stony Brook University, said the Shafritz discovery is important because it helps 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.

“Some kids will take 100 crayons and line them up over and over. If you move one of the crayons they get very upset. It might lead to a tantrum, a major outburst of problem behavior.”

Even though the brain mapping revealed sites associated with repetitious behavior, Shafritz emphasized these areas are not associated with injurious acts, which may occur as a result of dysfunctions elsewhere in the brain. Some children repeatedly slam their heads against a wall and indulge in other self-injurious behavior.

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 Malhotra, director of psychiatric research at Zucker Hillside Hospital, said he is not surprised. He, too, is studying links between autism and schizophrenia, and autism and obsessive compulsive disorder.

“This is an area of great interest,” Malhotra said, adding that autism and schizophrenia are related because both disorders are marked by problems with social interaction.

“We also see an overlap between (obsessive compulsive disorder) and autism,” Malhotra said.