Quoting from the 01-16-06 issue of TIME magazine, an article entitled "The Surprising Power of the Aging Brain" by Jeffrey Kluger--

...Risk-taking seniors making daring mental leaps? That's not the stereotype. Indeed, until quite recently most researchers believed the human brain followed a fairly predictable developmental arc. It started out protean, gained shape and intellectual muscle as it matured, and reached its peak of power and nimbleness by age 40. After that, the brain began a slow decline, clouding up little by little until, by age 60 or 70, it had lost much of its ability to retain new information and was fumbling with what it had. But that was all right because late-life crankiness had by then made us largely resistant to new ideas anyway.

That, as it turns out, is hooey. More and more, neurologists and psychologists are coming to the conclusion that the brain at midlife—a period increasingly defined as the years from 35 to 65 and even beyond—is a much more elastic, much more supple thing than anyone ever realized.

Far from slowly powering down, the brain as it ages begins bringing new cognitive systems on line and cross-indexing existing ones in ways it never did before. You may not pack so much raw data into memory as you could when you were cramming for college finals, and your short-term memory may not be what it was, but you manage information and parse meanings that were entirely beyond you when you were younger. What's more, your temperament changes to suit those new skills, growing more comfortable with ambiguity and less susceptible to frustration or irritation. Although inflexibility, confusion, and even later-life dementia are very real problems, for many people the aging process not only does not batter the brain, it actually makes it better. ...

As we age, .. the walls between the hemispheres seem to fall, with the two halves working increasingly in tandem. Neuroscientist Roberto Cabeza of Duke University dubs that the HAROLD (hemispheric asymmetry reduction in older adults) model, and judging by his work, the phenomenon is a powerful one.

Cabeza recruited a sample group of adults 65 to 95 years old who had scored high on a memory test, along with a group of lower-performing adults of the same age and a group of younger, college-age adults. He then asked them all to perform a series of tasks that called on numerous skills, including language, memory, perception and motor functions. Throughout the tasks, he conducted functional magnetic resonance imaging scans of their brains. Again and again, he found that the high-functioning older adults were using either a hemisphere different from the one the other subjects were using or both hemispheres at the same time.

Why that is so is still unclear, but Cabeza doesn't believe the brain is programmed to get stronger as it ages. Rather, he acknowledges, in many ways it gets weaker, with neurons processing information less efficiently. The bilateralization may be a trick the brain uses to compensate for the decline, sometimes integrating the hemispheres so efficiently that our thought and reasoning processes are actually better than they were before. ...

Journal entry dated 04 April 2006
Category: Eye on a world becoming