大脑老化不一定是坏事?

在大众的观念当中,大脑的不断老化所伴随着都应该是一些负面的信息,如记忆力退化,反应迟钝等等,而加州大学洛杉矶分校的某项研究发现事实并非如此,想了解其中的奥妙吗?那就让我们跟着Gary Small一起来了解吧!

March 1, 2010 - MICHELLE TRUDEAU: I'm Michelle Trudeau. Just as in adolescence, there's good news and bad news about the brain in middle age, and ways researchers tell us to maintain good brain health. First, the bad news for us middle-agers.

Dr. GARY SMALL (Director, UCLA Center on Aging): Reaction time is slower. It takes us longer to learn new information.

TRUDEAU: That's research psychiatrist Gary Small, from UCLA.

Dr. SMALL: Sometimes it takes us longer to retrieve information, so we have that tip-of-the-tongue phenomenon. That's typical of a middle-age brain.

TRUDEAU: Any more bad news?

Dr. SMALL: We're not so great at multi-tasking. We're quick, but we're sloppy. We make more errors when we're middle-aged.

TRUDEAU: Is there any good news?

Dr. SMALL: Complex reasoning is very good when we get older, as we age.

TRUDEAU: Small explains that myelination, the insulation wrapped around each nerve cell that increases conductivity, reaches its maximum in middle age.

Dr. SMALL: So that means that the neural circuits fire more rapidly, so you're going from dial-up to DSL.

TRUDEAU: And Small adds empathy to our plus column.

Dr. SMALL: If you design an experiment, and you present several options for a young person, they're more likely to choose a more narcissistic option than one that tends to take into account the other person's interest and point of view than, say, a middle-age or older person would.

TRUDEAU: One of the great discoveries from recent neuroscience research is that our brains are always changing, always developing, even able to grow new brain cells.

In a recent study, one he calls "Your Brain on Google," Gary Small trained healthy, middle-aged folks who were novices on the computer to do Google searches. They practiced searching online an hour a day for a week, and then came back into the lab for brain scans. The scans showed significant increases in brain activity in the areas that control memory and decision-making.

Dr. SMALL: One interpretation of that is that with practice, very quickly, an older brain can alter its neural circuitry, can strengthen those neural circuits controlling working memory, controlling decision-making areas of the brain.

TRUDEAU: Research by neuroscientist Art Kramer, at the University of Illinois, demonstrates the plasticity, or the ability to grow and change, of the aging brain. In his studies on physical exercise, memory improves with aerobic, treadmill training.

Dr. ART KRAMER (Neuroscientist, University of Illinois): So what we find is that over a six-month to a one-year period, at three days a week, working up to an hour a day, that people improve in various aspects of both short-term and long-term memory.

TRUDEAU: And people who exercised had larger hippocampi, a critical memory center. Other brain areas, too central for decision-making, planning and multi-tasking were also larger, larger than when they began the aerobic exercise program.

Dr. KRAMER: There are number of regions that on MRI scans tend to show not just stability, but increases as a function of exercise in middle-age and older brains.

TRUDEAU: And these scientists are walking the walk. For all you baby boomers out there with middle-aged brains, heres what Dr. Kramer, age 56 and next, Dr. Small, age 58, do to keep their own brains healthy.

Dr. KRAMER: Before this interview, I was over at the gym, and I was riding a stationary bike and reading a few newspapers. And I was also lifting weights.

Dr. SMALL: And I'll start out in the New York Times, and I'll do "KenKen." And then either Ill solve it, or I get to the point where I screwed it up. And then I move on the crossword. That's my typical day.

For NPR News, I'm Michelle Trudeau.