EMBARGOED FOR RELEASE UNTIL 4 PM ET, April 14, 2002
Brain Undergoes Gains and Losses in Cognitive Abilities during Adolescence
Denver, Colo. -
The transition from childhood to adulthood means we gain some cognitive abilities, but lose others, according to a scientific paper presented at the American Academy of Neurology Annual Meeting in Denver, April 13-20. The conclusions from the relatively small study are preliminary. "Humans gain an expansion in the scope and depth of knowledge and comprehension during adolescence," according to study author Gabrielle M. de Courten-Myers, MD, of the University of Cincinnati College of Medicine. "However, about the same time we lose some ability to acquire new sounds and speech patterns. In this regard, adults are more limited than children." Researchers at studied the post-mortem cerebral cortexes of six 12- to 17-year-olds and five 17- to 24-year-olds. All of the individuals had been of normal health and intelligence. They studied 43 different areas in each brain hemisphere, measuring for cortical thickness, neuronal density and pyramidal neuronal size. Corrections were made for gender differences in the size of the brain. The average pyramidal soma size was 15.5 percent smaller in the older age group than in the younger one. This suggests that these nerve cells undergo "pruning" or "streamlining" of their processing during adolescence, said de Courten-Myers. Other measures of the brain were slightly larger in the older age group, including cortical thickness (1.9 percent), neural density (1.8 percent), the number of neurons/standard cortical columns (3.8 percent), neuropil volume/standard cortical column (3.1 percent), and neuropil volume/neuron (1.3 percent). The study was supported by the Foundation for the Prevention of and Research on Mental Retardation, Geneva, Switzerland.