The brains of very intelligent children develop differently than those of kids with average intelligence, according to a new study published in the journal Nature. The researchers say the study involving normal, healthy children, is ultimately intended to help children with serious emotional and neurological difficulties.
For the past 15 years, researchers at the U.S. National Institutes of Mental Health have been using high-tech brain imaging known as M.R.I. to look at the brains of just over 300 children between five and 11 years old.
According to researcher Philip Shaw, investigators have been trying to answer a number of questions. "And the one we were looking at here was do children's brains grow differently according to how clever they are?", he said.
Over the course of the study, each child underwent an M.R.I. at least once, while others had two or more brain scans at least two years apart.
During this same time period, the children also took intelligence tests that measured their verbal and non-verbal reasoning, which is associated with an area of the brain known as the frontal cortex.
Shaw says all of the children showed the same basic pattern of increased cortical thickening from a young age. "And we find the most intelligent children started off with a relatively thin cortex, but it then got thicker relatively rapidly, reached its peak thickness in certain key areas several years later but then also got thinner quicker," he said.
In the study, the brains of very intelligent kids reached their peak thickness around age 11, a couple of years ahead of children with average intelligence.
Shaw speculates on the effect of the extra development time. "It might reflect an extended period for the development of very high level, complicated brain circuits in this region which support very high level, complicated thought," he said.
Shaw hopes the data collected on the brain structures of healthy children will help scientists develop treatments for youngsters with serious brain disorders, including childhood onset schizophrenia and less severe conditions such as attention deficit hyperactivity disorder.
Mary Blue is a pediatric developmental disabilities researcher at the Kennedy Krieger Institute in Baltimore, Maryland. Blue notes that the study found only a slight, six to 12 percent difference in brain structure development among the children.
But she agrees that studies mapping a normal brain could help children with serious neurological difficulties. "This could be a measure that you could use to look at when you are applying therapies. So, if you use different kinds of therapies, can you actually change brain structure?," he said.
Meanwhile, Shaw and his colleagues are currently using data collected from the current study to see if they can pinpoint key differences between the brains of healthy children and those with severe disorders.