Progress

About a year ago, research showed that new neurons were produced in the hippocampus of human brains. Now scientists are looking at parts of the brain to see if new neurons are produced there, too. To look for new neurons, researchers use a chemical called bromodeoxyuridine, or BrdU for short. BrdU is incorporated into new cells, thus making them distinguishable from old cells. When researchers examine brain tissue, they can look for cells that contain BrdU.

Dr. Elizabeth Gould, a professor of Psychology at Princeton University, has reported (Science, October 15, 1999) that new neurons are added to other parts of the brain in adult macaque monkeys. These areas include those involved in "higher functions" such as learning, problem solving, and memory. Dr. Gould and her research group saw the generation of neurons in the prefrontal cortex, inferior temporal cortex, and the posterior parietal cortex. Each of these areas has been implicated in cognitive functions. The prefrontal region is thought to be involved in short-term memory and decision making; the inferior temporal area contributes to visual recognition (e.g., recognition of faces); and the posterior parietal cortex aids in interpreting the positions of objects in space.

This new study indicates that neurogenesis in the brain is more widespread than previously thought. If researchers can find out how new neurons appear, what conditions are necessary for generating new neurons, what factors need to be present or what chemicals must be absent, perhaps this information can be used to fight neurodegenerative diseases. Answers to these questions may provide treatments for disorders such as Alzheimer's disease and Parkinson's disease.