New Tool Shows How a Child's Brain Grows
The final period, from age 13-15, is perhaps the most surprising of all: Rapid growth ends abruptly, and the area of the brain that controls learned motor skills shrinks to about half its former mass, seeming to lose its ability to quickly learn new motor skills. "This is the area of the brain that, when you get better at a motor skill, takes over more and more of that function," Thompson says.
Thompson suggests that many severe developmental problems -- such as autism, dyslexia, and child-onset schizophrenia -- may not be caused as much by abnormal brain structure as by abnormal brain growth. If this is true, the new technique might be able to detect such problems before they become severe. He and coworkers are now studying abnormal children to see if this is the case. If so, pediatricians soon may have a powerful new diagnostic tool, and parents may one day be taking their children to the radiologist for regular brain scans.
However, not all experts in the field fully agree with Thompson's interpretation. USC's Mitchell says that changes in brain structure do not necessarily mean there have been changes in the way the brain works. "This [new MRI technique] shows you how things are growing and when, but there is more to it than that. You are seeing the pieces of the jigsaw puzzle, but not putting it together yet," she says.
In addition to studies of children with developmental abnormalities, Thompson and coworkers are looking in a completely different direction: Alzheimer's disease. In cooperation with SmithKline Beecham, they are exploring the use of the new MRI technique to measure the effects of new medications on the brain with Alzheimer's disease.