A personality profile marked by overly gregarious yet anxious behavior is rooted in abnormal development of a circuit hub buried deep in the front center of the brain, say scientists at the National Institutes of Health. They used three different types of brain imaging to pinpoint the suspect brain area in people with Williams syndrome, a rare genetic disorder characterized by these behaviors. Matching the scans to scores on a personality rating scale revealed that the more an individual with Williams syndrome showed these personality/temperament traits, the more abnormalities there were in the brain structure, called the insula.
"Scans of the brain's tissue composition, wiring, and activity produced converging evidence of genetically-caused abnormalities in the structure and function of the front part of the insula and in its connectivity to other brain areas in the circuit," explained Karen Berman, M.D., of the NIH's National Institute of Mental Health (NIMH).
Berman, Drs. Mbemda Jabbi, Shane Kippenham, and colleagues, report on their imaging study in Williams syndrome online in the journal Proceedings of the National Academy of Sciences.
"This line of research offers insight into how genes help to shape brain circuitry that regulates complex behaviors such as the way a person responds to others and thus holds promise for unraveling brain mechanisms in other disorders of social behavior," said NIMH Director Thomas R. Insel, M.D.
Williams syndrome is caused by the deletion of some 28 genes, many involved in brain development and behavior, in a particular section of chromosome 7. Among deficits characteristic of the syndrome are a lack of visual-spatial ability such as is required to assemble a puzzle and a tendency to be overly-friendly with people, while overly anxious about non-social matters, such as spiders or heights. Many people with the disorder are also mentally challenged and learning disabled, but s
|Contact: Jules Asher|
NIH/National Institute of Mental Health