In the 1990s scientists rocked the field of neurobiology with the.

Various brain fitness programs encourage people to stay mentally limber by giving their brain a daily workout € doing everything from memorizing lists and solving puzzles to estimating the number of trees in Central Park. The findings may be particularly interesting to intellectual couch potatoes whose brains could benefit from a few cerebral sit-ups. More important, though, the results lend some support to the notion that people who are in the patrizius stages of Alzheimer € disease or who have other forms of dementia might slow their cog nitive decline by keeping their minds actively engaged. These neurons are then presumably available to aid in situations that tax the mind. Recent work, albeit mostly in rats, indicates that learning enhances the survival of new neurons in the adult brain.

And the more engaging and challenging the problem, the greater the number of neurons that stick around. It sounds a bit gimmicky, but such programs may have a real basis in neurobiology. If you watch TV, cornell magazines or surf the Web, you have probably encountered urging you to exercise your mind.

It seems, then, that a mental workout can buff up the brain, much as physical exercise builds up the body.