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Brains of smart kids develop differently

Associated Press
Published March 30, 2006


NEW YORK - Very smart children, despite their reputation for being ahead of their peers mentally, actually lag behind other kids in development of the "thinking" part of the brain, a study says.

The brain's outer mantle, or cortex, gets thicker and then thins during childhood and the teen years. The study found that in kids with superior intelligence, the cortex reaches its thickest stage a few years later than in other children.

Nobody knows what causes that or how it relates to superior intelligence. But researchers said the finding does not rule out a role for environment - such as intellectual stimulation - in affecting a child's level of intelligence.

In fact, the brain's delay in thickening may promote higher intelligence because it means a child is older and processing more complex experiences while the cortex is building up, said Dr. Judith Rapoport, study co-author.

Rapoport, with researcher Dr. Philip Shaw and others at the National Institute of Mental Health in Bethesda, Md., followed development of the cortex in 307 children. They used repeated magnetic resonance imaging scans from childhood to the latter teens.

Results are published in the journal Nature. Researchers also found that despite the delayed schedule, the cortex thickens and thins faster in brilliant kids than in other children.

The overall findings are especially strong for cortex development in the front part of the brain and in a strip over the top of the head, areas where complex mental tasks are done, Shaw said.

One analysis found the cortex in kids with the highest IQs - 121 to 149 - didn't reach maximum thickness until age 11. Children who were just slightly less bright reached that point at age 9, and those with average intelligence at around 6. In all cases, the cortex later thinned as the children matured.

It's not known what is happening within the cortex to make it get thicker or thinner, Shaw said, so it's impossible to say why those changes would be related to intelligence.

Study finds no consensus on elective C-sections

WASHINGTON - Women who want several children should avoid the new trend of purely elective Caesarean sections - planned surgical births when there's no clear medical need - government advisers said Wednesday.

But for mothers-to-be who plan only one or two children, there's too little research to say definitively whether it's a good or bad idea.

So concluded scientists assembled by the National Institutes of Health who spent three days hearing an impassioned debate on the apparent rise in elective C-sections - only to conclude there are few easy answers.

"We don't believe it should be discouraged or encouraged," said Dr. Mary D'Alton, obstetrics chief at Columbia University Medical Center, who chaired the panel.

Instead, there are pros and cons to different methods of childbirth, and women and their doctors must work tailor the choice, the panel said.

"There's not one right answer for everyone," said panelist Barbara Hughes, a nurse-midwife at the University of Colorado Health Sciences Center.

Caesarean rates have reached an all-time high, 29 percent of U.S. births - a 40 percent increase since 1996, and a rise that shows no sign of tapering off.

No one knows how many of those C-sections are purely elective; some studies suggest there may be 80,000 or so a year.