Can you keep your brain from aging?

A special issue on neuroscience and neuroculture.
April 25 2007 8:55 PM

Train Your Brain

The new mania for neuroplasticity.

Click here for more from the Brains! special issue.

Train Your Mind, Change Your Brain by Sharon Begley

Not long ago, I began to get mild migraines that lasted a few days. The headaches weren't bad, but while they endured, it seemed to me, my memory began to grow newly … indefinite. I had never been good at remembering names of characters in books or movies. But now I couldn't remember the names for things like "sideboard" or "remote control" or "Graydon Carter." Had early senility taken hold? Or was this the hidden price of today's chaotic information-age lives—of answering hundreds of e-mails while juggling phone calls and text messages, jumping every time Outlook went ping? So I did what it seemed everyone else was already doing: I began a regimen of crossword puzzles, Sudoku, and physical exercise to try to reduce my "brain age." I could only hope irreparable damage hadn't already been done.

That the brain—as distinct from the mind—is in cultural vogue is hardly news. The 1990s, after all, were pronounced "The Decade of the Brain" by George Bush. For years, Op-Ed columnists have invoked genetic determinism, fMRI neural imaging scans, and evolutionary psychology at the drop of a hat. But it is only in the 21st century, as advances in brain science have vastly expanded what we know about the 3-pound organ, that we've learned that genetic determinism isn't our fate. Instead, we might be able to get the brain we want—the brain we feel we really deserve.

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Welcome to the age of neuroplasticity: the notion that adult brains are more adaptable, capable of reprogramming themselves, than was once thought. As a host of popularizers have begun to argue, neuroplasticity has enormous implications not only for our physical health but for our mental health. One recent example, Sharon Begley's Train Your Mind, Change Your Brain: How a New Science Reveals Our Extraordinary Potential To Transform Ourselves, aims to harness the self-improving yen of aging baby boomers while couching the desire in highbrow guise (offering up a dash of Buddhism, a short history of Tibet, a little biology). Even more than evolutionary psychology—yesterday's brain cause du jour—neuroplasticity has become fundamental to how we try to understand the brain, and ourselves.

This new perspective is grounded in (somewhat) recent, solid scientific findings. For decades, it was assumed by many neuroscientists that adult humans had a "hardwired" brain that did not generate new cells and could not significantly change. As the Spanish neuroanatomist Ramón y Cajal put it in 1913, the adult human brain was "fixed, ended, immutable." Scientists believed that if an adult lost her sight, her visual cortex (the area in the brain where visual stimuli are processed) would become a neuronal black hole, as it were; if she lost feeling in her arm, the section of her cortex allotted to arm sensations would go silent. Only children had malleable brains, capable of readily absorbing information (like new languages), and receptive to whatever programming (Mozart, Baby Einstein, an affection for smoked mozzarella) instrumental-minded adults tried to cram into it. The rest of us were stuck with our creaky memories and our paltry mastery of French; there was no way to stop and call for a "do-over."

That this wasn't entirely the case was suspected by a handful of scientists as early as the 1920s. In 1923, researcher Karl Lashley discovered evidence that the brain of an adult rhesus monkey was fairly changeable, with neurons following different paths from week to week in response to the same stimuli. Such evidence led him to suspect that "a plasticity of neural function" allowed the motor cortex to "remodel itself continuously to reflect its owner's recent patterns of movement," as Begley puts it. By the 1950s, there was much more evidence for such plasticity, but the neuroscientific establishment resisted the notion, holding on to the idea that the brain could not regenerate or heal itself following injury. In the 1970s, a researcher named Michael Merzenich discovered that when he severed a nerve ending in the hands of adult monkeys, the monkeys' brains quickly "rewired" to continue to use the region of the somatosensory cortex that, according to conventional wisdom, should have gone dark; the brain had begun to process signals from other parts of the hand, where the monkey could still feel. As studies accumulated, the certainty in the neuroscientific façade began to crack.