Brains of Children and Adolescents Inefficient, Details Emerge

More details are emerging from research at the Ecole Polytechnique Fédérale de Lausanne (EPFL) and the University of Lausanne (UNIL). Swiss scientists worked with researchers from Harvard and the Indiana University to map the brains of 30 children from age 2 to age 18.

A young child's brain is similar to the early Internet with isolated, poorly linked hubs and inefficient connections, say the researchers from EPFL and UNIL. An adult brain, on the other hand, is more like a modern day, fully integrated fiber optic network. The scientists hypothesized that while the brain does not undergo significant topographical changes in childhood, its white matter -- the bundles of nerve cells connecting different parts of the brain -- transitions from weak and inefficient connections to powerful neuronal highways. To test their idea, the team worked with colleagues at Harvard Medical School and Indiana University to map the brains of 30 children between the ages of two and 18.

With MRI, they tracked the diffusion of water in the brain and, in turn, the fibers that carry this water. Thiran and UNIL professor Patric Hagmann, in the Department of Radiology, then created a database of the various fiber cross-sections and graphed the results. In the end, they had a 3D model of each brain showing the thousands of strands that connect different regions.

These individual models provide insight not only into how a child's brain develops but also into the structural differences in the brain between left-handed and right-handed people, for example, or between a control and someone with schizophrenia or epilepsy. The models may also help inform brain surgeons of where, or where not, to cut to relieve epilepsy symptoms. _SD

We also know that the brain continues to mature into the middle and later 20s, with improved frontal lobe development and myelination. Some individuals may not achieve maximum maturation until they are nearly 30 years of age. (Psychological neotenates, of course, tend to never mature)

Unfortunately, the energy of youth begins to subside at almost the same time that the brain achieves its maximum power. The brain itself continues to change and develop throughout the rest of a person's life, but the absolute computing power of the brain -- for most persons -- begins to subside sometime in the 40s. This is most clearly seen in the careers of mathematicians and theoretical physicists, whose individual novel contributions generally drop off rapidly after they reach their 50s.

The experience and wisdom a person may accumulate in adulthood often helps to compensate for the loss of thinking speed and absolute cognitive power. As population demographics in the developed world continues to shift toward an older population, some of these issues will need to be confronted -- more money will need to be spent on research into reversing the mental and physical decline of aging.