Secret Life of the Grown-Up Brain (2 page)

What’s more, middle age is a far more important time for our brains than anyone ever suspected. This is when paths diverge. What we do when we’re on Planet Middle Age determines what the next stop, Planet Old Age, will look like. As one neuroscientist told me, at midlife, the brain is “on the cusp.” What we do matters, and even what we think matters.

Over the years, we’ve been trained to think that the body and the brain age in tandem. Certain bodily changes are undeniable. Despite my best efforts—the regular runs, the laps at the YMCA pool, the yoga—I’m twenty pounds heavier than I ever was before. I need glasses that correct for three different distances—reading, driving, and writing on a computer. My hair, without help, is an undistinguished brownish gray, my face has deep lines. Sometimes, catching a glimpse of myself in a mirror or a window, I think, for a quick moment, that I’m really looking at my mother.

And as we watch the hair on our heads turn gray or disappear altogether, we assume that there’s equivalent decay inside our heads. It’s not hard to imagine our neurons turning their own shades of brownish gray, drying up, or disappearing altogether, too.

But what’s actually happening turns out to be much more complicated. And researchers—from sociologists and psychologists to neuroscientists—have discovered that middle-aged brains do not necessarily act like the rest of our bodies at all.

So what do we know?

What is known of middle age now comes to us from the results of major studies just now emerging of how people actually live their lives, as well as from research from labs all over the world that are now dissecting the experience of middle age, brain cell by brain cell.

Our brains vary greatly in terms of which functions decline and which maintain their capacities, or even reach their height, in middle age and beyond. Parts of our memory—certainly the part that remembers names—wane. But at the same time, our ability to make accurate judgments about people, about jobs, about finances—about the world around us—grows stronger. Our brains build up patterns of connections, interwoven layers of knowledge that allow us to instantly recognize similarities of situations and see solutions.

And because of our generally healthy childhoods—compared with earlier generations—most cognitive declines of consequence are not occurring for those in middle age now until much later than even our parents’ generation. There’s also evidence that as a group we’re considerably smarter than any similarly aged groups that went before us.

Much of what I’ve written here is quite new. Even as I wrote the book, various interpretations of some findings were still being hotly debated.

As it’s come into focus and scrutiny, middle age has attracted its own rumors, fantasies, and ghosts. With the current deeper understanding of what actually happens, however, many of those ghosts are disappearing. The midlife crisis, for instance, that currency of cocktail-party conversation, turns out on closer inspection to have little grounding in reality. The empty-nest syndrome, another staple of our expectations of middle age, is equally rare, if not imaginary.

In fact, scientists have found that moving into middle age for most is a journey into a happier time. In particularly hard or stressful moments it might not seem likely, but around middle age, we start growing happier, and the cause may be aging itself. The positive wins out over the negative in how we see the world, in part because we start to use our brains differently. There may be evolutionary reasons for this, too. A happier, calmer middle-aged human is better able to help the younger humans in his care.

Clearly, the middle-aged brain is no longer pristine. Researchers meticulously tracking the brain as it ages in humans and animals see distinct declines in the chemicals that make our brains function—the neurotransmitters, such as dopamine, that keep us alert and on the move. There’s a decrease in brain branches, where neurons communicate. There’s new—very new—work that has found a whole new brain state—a default mode. This is a kind of daydreaming state of quiet and continuous inner chatter where our brains increasingly go as we age, leaving us distracted, and confirmation of its existence is considered one of the most important discoveries ever made about how brains operate and age.

What’s more, one scientist at Pomona College in California has now carefully documented what, in fact, happens when we forget names, why it starts in middle age, what it might mean, and why, for heaven’s sake, we can remember that a person works as a banker but cannot remember that his name is Bob. There is now general agreement that some brain functions simply do not keep up, particularly what scientists like to call processing speed. If you think, at age fifty-five, that you’ll be able to keep pace in all areas with an average twenty-five-year-old—to swerve as quickly to avoid a squirrel in the road or adjust as quickly to yet another new computer system at work—think again.

But in the end, a name here or there or a top rate of brain speed may not matter so much. While losses occur by middle age in our brains, they are neither as uniform nor as drastic as we feared. Indeed, even the long-held view that our brains lose millions of brain cells through the years has now been discounted. Using brain scanners and watching the brains of real people aging in real time, researchers have now shown that brain cells do not disappear in large numbers with the normal aging process. Most stick around for the long haul and, given half a chance, can be there—intact and ready—well into our eighties and nineties and perhaps beyond.

Neuroscientists at UCLA and elsewhere can now watch parts of brain cells—in particular, the fatty white coating of neurons called myelin—continue to grow late into middle age. As myelin increases, it builds connections that help us make sense of our surroundings. This growth of white matter, as one Harvard scientist has put it, may in itself be “middle-aged wisdom.” There’s new interest, too, in defining what exactly wisdom is. We talk glibly of someone being wise, but what does that mean? How is such a thing stored in a brain and made use of in the day-to-day life of a fifty-year-old mother of teenagers or a sixty-year-old professor? For many years, what we call experience was also taken for granted. But experience is now being broken into its component parts and we’re learning exactly how experience physically changes the brain, which kinds of experience alter the brain for the better, and what it really means to be a competent manager, a prudent pilot, or a gifted teacher.

There are recent findings, too, that show how the middle-aged brain—rather than giving up and giving in—adapts. As we age, our brains power up, not down, and use more of themselves to solve problems. And it is those with the highest functioning cognitive skills who learn to use their brains this way. In some cases, as researchers at Duke University and elsewhere have found, people in middle age begin to use two sides of their brains instead of one—a trick called bilateralization. Those who recruit—or learn to recruit—the strength of their brains’ powerful frontal cortex, in particular, develop what scientists call “cognitive reserve,” thought to be a buffer against the effects of aging. This is the kind of brain strength that helps us get the point of an argument faster than younger peers—to get the gist, size up a situation, and act judiciously rather than rashly. This brain reserve may also help us ward off early outward symptoms of diseases such as Alzheimer’s. And there are strong hints that something as simple as education—or working—may be the key to building this brain buffer for a lifetime.

The question this leaves us with, of course, is, how can we both develop that buffer and keep it. If we’re lucky enough to remain relatively healthy, can we push our brains to remain strong beyond middle age? To get that answer, science first has to tease out exactly what constitutes normal aging and what is pathology and illness. Since for years most aging research was conducted largely in nursing homes, we’ve had an overly negative view of what it means to get old. For many years, even most doctors thought dementia was inevitable.

But now we know that dementia, while its risks certainly increase with age, is a specific disease. If we maintain a normal path of aging without major illnesses, our brains can stay in relatively good shape.

So what do we need to do?

In the last part of the book, I explore the science of brain improvement, an area steeped in hype. What do we really know about the magic of eating blueberries or omega-3’s anyhow? Does exercise make a difference, and, if so, what kind and how?

At Boston University Medical School, neuroscientist Mark Moss is studying middle-aged monkeys to find out how normal aging happens and what can keep middle-aged brains intact. Is it fish oil? Red wine? Hours on the elliptical trainer? Elsewhere scientists are testing starvation diets to see why low-calorie diets seem to prolong lives, or why poor diets, high in fat and sugar, are harmful. One top researcher at the National Institutes of Health, for instance, has been severely limiting his own caloric intake since he was in graduate school, to see if he can maintain his brain’s vitality, ward off disease, extend his own life—and figure out how to prolong ours, too. Newer studies are asking what it is about obesity or high blood pressure that might increase the risks of dementia. Far beyond simply suggesting that a glass of wine or a bunch of blueberries is beneficial, researchers are now looking closely at the chemical makeup of certain foods. Is it the dark color of the fruit’s skin that helps our cells stay healthy? Is it the antioxidants? How many glasses of wine do we have to drink anyhow? Can we find a pill that will work instead?

One way to measure how excited a particular group of scientists is about the potential of their field is to follow the money. And there is now real money behind various ideas about how to extend the useful life of our brain cells. Now that science knows that we do not lose millions of neurons as we age, it seems suddenly plausible that we can, if we look hard enough, find easier ways to keep our brain cells in top form. There’s increasing talk of “druggable” targets to help the brain as it ages, and a number of top scientists have begun their own companies in the hopes that once that target is found, there will be money to be made. Indeed, one top researcher I know said the biggest change she’s seen over the past few years has been that legitimate scientists are now talking unabashedly about possible brain “interventions,” including drugs that may be within reach.

For many researchers working on the aging brain, this new culture of possibility is a surprise. But then, as we watch ourselves age, many of us, too, are finding that we have to reconsider how we think about our own brains—and our own lives—as we enter and traverse middle age.

In an essay in 2007, author Ann Patchett expressed her own surprise at the evolving talents she has found in her brain as she reaches middle age. Even as her skin droops, Patchett has discovered that her mind is maturing.

“I was searching through files of photographs recently . . . when I found the proof sheets from a photo shoot I had sat for in 1996,” she wrote. “I was 32 years old, and I looked good. I mean really good: clear-eyed, sharp-jawed, generally lanky and self-possessed. . . .

“Looking at them now . . . I was struck by the fact that even though I am devoted to yoga and eat and get loads of rest and take vitamins and do all the other things you’re supposed to do to maintain the lustrous beauty of youth, I looked much better 11 years ago.”

But “I was also struck by the fact that I am smarter now. . . . My mind . . . is like a bank account and every investment I make seems to grow with a steady rate of interest. I am hoping that it will be there to keep me company as I age and that it will remain curious and agile. I’m working hard on it. And I do so love the work.”

As I wrote this book, I, too, began to view my own brain with a new respect.

When you actually take a moment to watch what a middle-aged brain does—and does with ease—it can come as a surprise. But it is also comforting. Over and over, when I told others I was writing a book about the brain in middle age, I would be met with suspicious glances. Then, after a moment, those same people, all middle-aged, would say things like, “Well, you know I am a better teacher now,” or, “Oh, well, yes, I am a better parent now.” Certainly, during middle age, we have a lot going on, a lot on our minds. But many of those in middle age told me that, rather than just feeling overwhelmed, they are, on some level, quite proud of what they can accomplish. One sixty-year-old friend put it another way: “My brain feels like one of those blueberries they keep telling us to eat,” she said. “You know, finally ripe and ready and whole.”

And that leaves the final—and perhaps most important—question. And that is, if our brain does in fact retain its strength— and we find methods of maintaining that strength—what shall we do with it?

The trappings and timetables of our lives are woefully out of date—set up for long-ago life spans in which by middle age we were expected to curl up—and give up. But if—as current trends indicate—many of us manage to live well into our eighties and nineties, and if we manage to keep our brains intact during that time, what will we be doing?

The world is set up to treat a middle-aged brain not as ripe, ready, and whole, but as diminished, declining, and depressed. We set up mandatory retirement ages that have little bearing on current lives. We tell teachers, lawyers, writers, and bankers they’re too old to work and we send them home—to do what?

Part One: The Powers That Be

1 Am I Losing My Mind?

Sometimes, but the Gains Beat the Losses

I’m standing in my basement.

I’ve come downstairs to get something. The question is, what?

I look around, trying to jog my memory. I stare at the shelves where I store big pots and pans. Was it the pasta plate? My mind is suddenly, inexplicably, blank.

I stare at my hands. Maybe if I look at my hands long enough, I’ll get a picture in my mind, a clue as to what I came down to the basement to put into those hands.