Exercising the Brain

Innovative training software could turn back the clock on aging brains.

Baby boomers regularly head to the gym to combat middle-age spread. Now evidence is piling up that exercising the aging brain is just as important.

A new cognitive training program designed to rejuvenate the brain's natural plasticity could slow down mental decline by as much as ten years. The program and others like it may be an accessible way for older people to take advantage of recent advances in the neuroscience of aging.

The connections in the brain are plastic, meaning that when we learn something, the properties of our synapses and other neural circuits change, improving their processing speed and the fidelity of the information being encoded.

As we age, though, this natural learning process starts to deteriorate. "Sensory information gets encoded less accurately, and the brain has to look and listen longer before it can make a decision about what it's seeing or hearing," says Michael Merzenich, a neuroscientist at the University of California at San Francisco, who's been studying the neural basis of learning for 30 years.

This slowing is at the root of some age-related memory loss. For example, older persons are significantly worse than college-age ones at remembering two musical tones presented in quick succession. But if the stimuli are slowed down by just a few hundred milliseconds, giving the subject more time to process the information, the difference in performance disappears.

Recent research has shown that reading the newspaper or doing crossword puzzles can help to keep older people mentally fit. According to Merzenich, a more focused and rigorous approach will have a considerably larger impact. In 2003, he founded the for-profit Posit Science in San Francisco to develop a software program based on the idea that individuals can retrain their brains to think faster, similar to the way, say, a retired violinist can recover his or her skill at the instrument with more intense practice.

During the training sessions that Merzenich and collaborators have conducted subjects answer questions about recorded narratives. The narratives are first played slowly, then progressively faster. The program adapts to the individual's skill level, so that the listening task is always difficult but not insurmountably so.

Experts say this level of challenge is a crucial component for triggering the brain's plasticity, which underlies improvements in processing speed. "This is what good rehab therapists do, but most people don't have the money to do that," says Michael Kilgard, a neuroscientist at the University of Texas at Dallas, who works with Posit. "We think it's possible to deliver this with a computer, rather than one-on-one."