July 29, 2013
The New Yorker
Patricia Marx

Workouts at the brain gym

Do I seem smarter than I did a few weeks ago? Since then, I’ve spent many hours in front of my computer, challenged by crucially important questions, like which two butterflies of the five that flickered onscreen for seventy-nine milliseconds were the matching pair, whether the ripples that rippled across the little magenta square went this way or that way, and how many more drills I must complete before I’m smart enough to date Harold Bloom. Remember when we called these sorts of activity video games and yelled at our kids for playing them? Now we refer to them as brain exercises, and we hope and trust that our digital exertions will make us as mentally agile as teen-agers wielding M27 assault rifles in Call of Duty: Black Ops II.

Teen-agers, I said—not twenty-seven-year-olds. That’s because most neuroscientists believe that by our late twenties the speed of our mental processing has begun to ebb, and so has our attention prowess and our working memory—i.e., the scratch pad in our minds that allows us to remember information long enough to calculate the tip on the taxi fare or . . . wait, what was I saying? While it is consoling that our vocabulary improves over the years, and that we oldsters are better at big-picture thinking and are more empathetic, still, by the advanced age of twenty there is a very good chance that our prefrontal cortex (the brains of the brain, responsible for problem-solving, decision-making, and complex thought) has already begun to shrink. We humans, by the way, are the only animals whose brains are known to atrophy as we grow older, and—yay, us again—we are also sui generis in suffering from Alzheimer’s disease. As distinctions go, this may not be as auspicious as, say, the opposable thumb. Nor is it necessarily the first chapter of a story that ends with being found wandering through Central Park in your pajamas. I’m also not guaranteeing that this might not happen to you. At an Alzheimer’s Association conference in Boston last week, researchers described a newly coined condition called “subjective cognitive decline.” According to a front-page article in the Times about these ominous findings, “People with more concerns about memory and organizing ability were more likely to have amyloid, a key Alzheimer’s-related protein, in their brains.” For the time being, there is nothing we can do about the amyloids, but in the past few years scientists and entrepreneurs have been claiming that there are measures one can take to minimize, slow down, or even reverse cognitive decline. With my fingers crossed, I travelled around the country to meet some of these authorities and find out how I could turbocharge my brain.

As recently as a few decades ago, most biologists thought that the brain was fully formed during childhood and, like a photograph after it’s been developed, was doomed to degrade thereafter, with neurons (nerve cells) fading like pigment on paper until you succumbed to senility. Today, we regard Alzheimer’s and other dementias as diseases, rather than as a consequence of normal aging. Moreover, we now consider the brain to be as labile as a digital image in the hands of a Photoshop fiend. The three-pound, pinkish-gray wrinkly guck in your skull contains about a hundred billion neurons. Each neuron can hook up with up to ten thousand others; hence, there are at least a hundred trillion neural connections in your brain, which is more than there are stars in the Milky Way galaxy. Not only does the brain have a lifelong ability to create new neurons; like a government with an unlimited highway budget, it has an endless capacity to build new roadways. Networks of linked neurons communicate chemically and electrically encoded data to one another (Hey, neuron, the keys are on the table) at junctures called synapses. Fresh neural trails are generated whenever we experience something new—learn the tango, try a liverwurst canapé, take a different route to work. Repeat the activity and the pathway will be reinforced. This is why London cabbies, whose job requires them to memorize a mesh of twenty-five thousand streets and thousands of landmarks, were found to have larger hippocampi than the city’s bus drivers, who are responsible for learning only a few routes. (The hippocampus plays a major role in memory.) The ability of the brain to establish new connections is called plasticity, and brain-fitness exercises are predicated on this mechanism. Working out has also been shown to revamp the brain and prevent it from shrinking. That’s enough science for now. Let’s get back to me. . . .