New Tool Shows How a Child's Brain Grows

May Some Day Help Doctors Assess Children's Development

By Daniel J. DeNoon
WebMD Medical News

March 13, 2000 (Atlanta) -- Is my child normal? A new brain mapping technique promises to give pediatricians a way to answer -- and also may point to the best times to teach children language and motor skills.

"Between the ages of 3 and 15 there is almost a forest fire of growth beginning at the front of the brain and moving back to the center," the co-developer of the technique, Paul M. Thompson, PhD, tells WebMD.

Thompson and coworkers at the UCLA Laboratory of Neuroimaging (LONI) used a tool known as magnetic resonance imaging (MRI) to create 3-dimensional pictures of children's brains. The researchers used several of these pictures -- taken from two weeks to four years apart -- to create a single, computer-generated color image that shows exactly where growth is taking place in a child's brain. These images can be viewed on the LONI web site at
http://www.loni.ucla.edu/~thompson/JAY/Growth_REVISED.html

Because of the limitations of current MRI technology, which requires a person to sit very still for eight minutes, it was impossible to map the brains of normal children younger than 3 years of age. However, the researchers did manage to obtain images from one 3-year-old.

The results showed three distinct periods of brain growth. During the first period, between the ages of 3 and 6 years, there is furious growth in the front of the brain that controls planning and organization. Child neurologist Wendy Gayle Mitchell, who was not connected with the MRI studies, tells WebMD that as the front of the brain develops, a child begins to be able to interpret things instead of just responding to them. "Instead of just doing and seeing, you interpret; you can put things in an orderly way," she says. "You develop an awareness of your own ability to think." Mitchell is a professor in the Keck School of Medicine at the University of Southern California.

In the second period of brain growth, at age 6-13 years, the high growth rate moves back toward the middle of the brain to an area involved in language skills. "It appears clear that because language systems grow at such a tremendous rate at these ages, that [age 6-13] may be a key period to teach languages," Thompson says.

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.

 

© 2000 Healtheon/WebMD. All rights reserved.