THURSDAY, March 30 (HealthDay News) -- Researchers have discovered that the trajectory of cortical development in childhood, rather than overall size, more closely correlates with intelligence, according to a report in the March 30 issue of Nature.
Philip Shaw, M.D., from the National Institute of Mental Health in Bethesda, Md., and colleagues used magnetic resonance imaging to monitor cortical development in 307 children and teens as they matured. Children were scanned one or two times every two years and stratified into average (83-108), high (109-120), and superior (121-145) IQ groups based on test scores.
The researchers found that the relationship between cortical thickness and IQ varied with age, especially in the prefrontal cortex. A wax and wane of cortical thickness is observed as children mature, with a peak occurring in children with average IQ at around age 8. The researchers found that cortical thickness in children with the highest IQ peaked at age 11 to 12 but thinned as expected, although occurring rapidly.
"Studies of brains have taught us that people with higher IQs do not have larger brains. Thanks to brain imaging technology, we can now see that the difference may be in the way the brain develops," said NIH Director Elias A. Zerhouni, M.D., in a statement.
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