Miércoles 2 de Mayo de 2007, Ip nº 189

Train Your Brain
Por Meghan O'Rourke

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.

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.

But the recent wave of how-to literature inspired by the wonders of neuroplasticity has obviously been inspired as much by a perceived cultural need as by cut-and-dried scientific proof. In March, Newsweek ran a cover story about the benefits of exercise to the adult brain. The mania for Sudoku, which purports to keep the aging brain on its mental toes, has led to more than $250 million in revenue for the global Sudoku business over the past two years, according to the New York Times. And the appetite for Japanese-style "Brain Age" tests led Nintendo to develop one for the DS, its hand-held device; participants can calculate their brain age on a daily basis. This month's Men's Vogue has an article suggesting that such puzzles could make us smarter and even stave off Alzheimer's. Neuroplasticity certainly has capacious ramifications, but you could be forgiven for thinking that the mania for harnessing its supposed anti-aging benefits is just our latest form of magical thinking, invoked by baby boomers who've turned away from fussing over their children's brains to ward off their own eventual decline.

After all, the concept offers an almost too-apt, metaphoric expression of fears about the unmanageability of life in the Information Age: It promises that we can use the mind—our faculties of determination—to rewrite the "hard-wired" brain, overcoming both genetic determinism and the frazzling wear and tear of contemporary connected life. One of the most interesting studies showed that only voluntary exercise reshapes the brain, and Begley turns to studies of monks to argue that meditation leads them to have higher rates of compassion toward the fellow man—as evidenced by the increased "gamma signal" activity in their brains. With its emphasis on mindful self-improvement, then, neuroplasticity answers a contemporary frustration with the chaotic connectivity of daily life while implying that we can have our connection and sever it too, so to speak: Just stop e-mailing for a few days and practice meditation, before starting the cycle all over again. It's a low-cost promise of regeneration.

Unfortunately, it is a promise that is almost certainly inflated. The notion of neuroplasticity as a life-altering "therapy" that might keep us on our mental toes into our 90s—as well as prime us for greater compassion toward our fellow man—does not rest on substantial, uncontested evidence. As Begley herself reported in the Wall Street Journal last spring, the effects of Brain Age-style games like Sudoku appear to be minimal in some respects. One study of elderly people (ranging in age from 65 to 94) found that while training in a particular task did help performance in that task, it did not improve cognitive function in other tasks, nor did it slow the participants' overall decline in cognitive function. More peculiarly, declines in function were the most extreme over time in those who had received training than those who had not. (Timothy Salthouse, who analyzed the study, told Begley this might reflect the fact that "if performance rises, it has farther to fall.") As Begley points out, many scientists now pooh-pooh the "use-it-or-lose-it" theory of mental functioning. Instead, they argue that it is "cognitive reserve" built up largely before the age of 30, not ongoing mental training, that benefits aging adults. That is, those 70-year-olds who were particularly smart 30-year-olds have more of a cushion to draw on than peers who were only average at 30 and therefore don't decline as far with age.

Be that as it may, the idea that a little mindful meditation could calm down the forgetful, buzzing frenzy of our brains is still an appealing one. Even if the science is less than solid, maybe the placebo effect will kick in; and in any case, my brain seems to enjoy its crossword-puzzle respites and its Sudoku vacations, the way my muscles enjoy a massage. Or so my mind is telling me. Seven-letter word for "memory loss," anyone?

  25/04/2007. Slate Magazine.


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