The Brain That Changes Itself PDF

The Brain That Changes Itself Stories of Personal Triumph from the Frontiers of Brain Science NORMAN DOIDGE, M.D. For Eugene L. Goldberg, M.D., because you said you might like to read it Contents 1 A Woman Perpetually Falling... Rescued by the Man Who Discover...

The Brain That Changes Itself Stories of Personal Triumph from the Frontiers of Brain Science NORMAN DOIDGE, M.D. For Eugene L. Goldberg, M.D., because you said you might like to read it Contents 1 A Woman Perpetually Falling... Rescued by the Man Who Discovered the Plasticity of Our Senses 2 Building Herself a Better Brain A Woman Labeled "Retarded" Discovers How to Heal Herself 3 Redesigning the Brain A Scientist Changes Brains to Sharpen Perception and Memory, Increase Speed of Thought, and Heal Learning Problems 4 Acquiring Tastes and Loves What Neuroplasticity Teaches Us About Sexual Attraction and Love 5 Midnight Resurrections Stroke Victims Learn to Move and Speak Again 6 Brain Lock Unlocked Using Plasticity to Stop Worries, OPsessions, Compulsions, and Bad Habits 7 Pain The Dark Side of Plasticity 8 Imagination How Thinking Makes It So 9 Turning Our Ghosts into Ancestors Psychoanalysis as a Neuroplastic Therapy 10 Rejuvenation The Discovery of the Neuronal Stem Cell and Lessons for Preserving Our Brains 11 More than the Sum of Her Parts A Woman Shows Us How Radically Plastic the Brain Can Be Appendix 1 The Culturally Modified Brain Appendix 2 Plasticity and the Idea of Progress Note to the Reader All the names of people who have undergone neuroplastic transformations are real, except in the few places indicated, and in the cases of children and their families. The Notes and References section at the end of the book includes comments on both the chapters and the appendices. Preface This book is about the revolutionary discovery that the human brain can change itself, as told through the stories of the scientists, doctors, and patients who have together brought about these astonishing transformations. Without operations or medications, they have made use of the brain's hitherto unknown ability to change. Some were patients who had what were thought to be incurable brain problems; others were people without specific problems who simply wanted to improve the functioning of their brains or preserve them as they aged. For four hundred years this venture would have been inconceivable because mainstream medicine and science believed that brain anatomy was fixed. The common wisdom was that after childhood the brain changed only when it began the long process of decline; that when brain cells failed to develop properly, or were injured, or died, they could not be replaced. Nor could the brain ever alter its structure and find a new way to function if part of it was damaged. The theory of the unchanging brain decreed that people who were born with brain or mental limitations, or who sustained brain damage, would be limited or damaged for life. Scientists who wondered if the healthy brain might be improved or preserved through activity or mental exercise were told not to waste their time, A neurological nihilism — a sense that treatment for many brain problems was ineffective or even unwarranted — had taken hold, and it spread through our culture, even stunting our overall view of human nature. Since the brain could not change, human nature, which emerges from it, seemed necessarily fixed and unalterable as well. The belief that the brain could not change had three major sources: the fact that brain-damaged patients could so rarely make full recoveries; our inability to observe the living brain's microscopic activities; and the idea — dating back to the beginnings of modern science — that the brain is like a glorious machine. And while machines do many extraordinary things, they don't change and grow. I became interested in the idea of a changing brain because of my work as a research psychiatrist and psychoanalyst. When patients did not progress psychologically as much as hoped, often the conventional medical wisdom was that their problems were deeply "hardwired" into an unchangeable brain. "Hardwiring" was another machine metaphor coming from the idea of the brain as computer hardware, with permanently connected circuits, each designed to perform a specific, unchangeable function. When I first heard news that the human brain might not be hardwired, I had to investigate and weigh the evidence for myself. These investigations took me far from my consulting room. I began a series of travels, and in the process I met a band of brilliant scientists, at the frontiers of brain science, who had, in the late 1960s or early 1970s, made a series of unexpected discoveries. They showed that the brain changed its very structure with each different activity it performed, perfecting its circuits so it was better suited to the task at hand. If certain "parts" failed, then other parts could sometimes take over. The machine metaphor, of the brain as an organ with specialized parts, could not fully account for changes the scientists were seeing. They began to call this fundamental brain property "neuroplasticity." Neuro is for "neuron," the nerve cells in our brains and nervous systems. Plastic is for "changeable, malleable, modifiable." At first many of the scientists didn't dare use the word "neuroplasticity" in their publications, and their peers belittled them for promoting a fanciful notion. Yet they persisted, slowly overturning the doctrine of the unchanging brain. They showed that children are not always stuck with the mental abilities they are born with; that the damaged brain can often reorganize itself so that when one part fails, another can often substitute; that if brain cells die, they can at times be replaced; that many "circuits" and even basic reflexes that we think are hardwired are not. One of these scientists even showed that thinking, learning, and acting can turn our genes on or off, thus shaping our brain anatomy and our behavior — surely one of the most extraordinary discoveries of the twentieth century. In the course of my travels I met a scientist who enabled people who had been blind since birth to begin to see, another who enabled the deaf to hear; I spoke with people who had had strokes decades before and had been declared incurable, who were helped to recover with neuroplastic treatments; I met people whose learning disorders were cured and whose IQs were raised; I saw evidence that it is possible for eighty-year-olds to sharpen their memories to function the way they did when they were fifty-five. I saw people rewire their brains with their thoughts, to cure previously incurable obsessions and traumas. I spoke with Nobel laureates who were hotly debating how we must rethink our model of the brain now that we know it is ever changing. The idea that the brain can change its own structure and function through thought and activity is, I believe, the most important alteration in our view of the brain since we first sketched out its basic anatomy and the workings of its basic component, the neuron. Like all revolutions, this one will have profound effects, and this book, I hope, will begin to show some of them. The neuroplastic revolution has implications for, among other things, our understanding of how love, sex, grief, relationships, learning, addictions, culture, technology, and psychotherapies change our brains. All of the humanities, social sciences, and physical sciences, insofar as they deal with human nature, are affected, as are all forms of training. All of these disciplines will have to come to terms with the fact of the self-changing brain and with the realization that the architecture of the brain differs from one person to the next and that it changes in the course of our individual lives. While the human brain has apparently underestimated itself, neuroplasticity isn't all good news; it renders our brains not only more resourceful but also more vulnerable to outside influences. Neuroplasticity has the power to produce more flexible but also more rigid behaviors — a phenomenon I call "the plastic paradox." Ironically, some of our most stubborn habits and disorders are products of our plasticity. Once a particular plastic change occurs in the brain and becomes well established, it can prevent other changes from occurring. It is by understanding both the positive and negative effects of plasticity that we can truly understand the extent of human possibilities. Because a new word is useful for those who do a new thing, I call the practitioners of this new science of changing brains "neuroplasticians." What follows is the story of my encounters with them and the patients they have transformed. Chapter 1 A Woman Perpetually Falling... Rescued by the Man Who Discovered the Plasticity of Our Senses And they saw the voices. Exodus 20:18 Cheryl Schiltz feels like she's perpetually falling. And because she feels like she's falling, she falls. When she stands up without support, she looks, within moments, as if she were standing on a precipice, about to plummet. First her head wobbles and tilts to one side, and her arms reach out to try to stabilize her stance. Soon her whole body is moving chaotically back and forth, and she looks like a person walking a tightrope in that frantic seesaw moment before losing his balance — except that both her feet are firmly planted on the ground, wide apart. She doesn't look like she is only afraid of falling, more like she's afraid of being pushed. "You look like a person teetering on a bridge," I say, "Yeah, I feel I am going to jump, even though I don't want to." Watching her more closely, I can see that as she tries to stand still, she jerks, as though an invisible gang of hoodlums were pushing and shoving her, first from one side, then from another, cruelly trying to knock her over. Only this gang is actually inside her and has been doing this to her for five years. When she tries to walk, she has to hold on to a wall, and still she staggers like a drunk. For Cheryl there is no peace, even after she's fallen to the floor, "What do you feel when you've fallen?" I ask her. "Does the sense of falling go away once you've landed?" "There have been times," says Cheryl, "when I literally lose the sense of the feeling of the floor... and an imaginary trapdoor opens up and swallows me." Even when she has fallen, she feels she is still falling, perpetually, into an infinite abyss. Cheryl's problem is that her vestibular apparatus, the sensory organ for the balance system, isn't working. She is very tired, and her sense that she is in free fall is driving her crazy because she can't think about anything else. She fears the future. Soon after her problem began, she lost her job as an international sales representative and now lives on a disability check of $1,000 a month. She has a newfound fear of growing old. And she has a rare form of anxiety that has no name. An unspoken and yet profound aspect of our well-being is based on having a normally functioning sense of balance. In the 1930s the psychiatrist Paul Schilder studied how a healthy sense of being and a "stable" body image are related to the vestibular sense. When we talk of "feeling settled" or "unsettled," "balanced" or "unbalanced," "rooted" or "rootless," "grounded" or "ungrounded," we are speaking a vestibular language, the truth of which is fully apparent only in people like Cheryl. Not surprisingly, people with her disorder often fall to pieces psychologically, and many have committed suicide. We have senses we don't know we have — until we lose them; balance is one that normally works so well, so seamlessly, that it is not listed among the five that Aristotle described and was overlooked for centuries afterward. The balance system gives us our sense of orientation in space. Its sense organ, the vestibular apparatus, consists of three semicircular canals in the inner ear that tell us when we are upright and how gravity is affecting our bodies by detecting motion in three-dimensional space. One canal detects movement in the horizontal plane, another in the vertical plane, and another when we are moving forward or backward. The semicircular canals contain little hairs in a fluid bath. When we move our head, the fluid stirs the hairs, which send a signal to our brains telling us that we have increased our velocity in a particular direction. Each movement requires a corresponding adjustment of the rest of the body. If we move our heads forward, our brains tell an appropriate segment of our bodies to adjust, unconsciously, so that we can offset that change in our center of gravity and maintain our balance. The signals from the vestibular apparatus go along a nerve to a specialized clump of neurons in our brain, called the "vestibular nuclei," which process them, then send commands to our muscles to adjust themselves. A healthy vestibular apparatus also has a strong link to our visual system. When you run after a bus, with your head bouncing up and down as you race forward, you are able to keep that moving bus at the center of your gaze because your vestibular apparatus sends messages to your brain, telling it the speed and direction in which you are running. These signals allow your brain to rotate and adjust the position of your eyeballs to keep them directed at your target, the bus. I am with Cheryl, and Paul Bach-y-Rita, one of the great pioneers in understanding brain plasticity, and his team, in one of his labs. Cheryl is hopeful about today's experiment and is stoical but open about her condition. Yuri Danilov, the team biophysicist, does the calculations on the data they are gathering on Cheryl's vestibular system. He is Russian, extremely smart, and has a deep accent. He says, "Cheryl is patient who has lost vestibular system — ninety-five to one hundred percent." By any conventional standard, Cheryl's case is a hopeless one. The conventional view sees the brain as made up of a group of specialized processing modules, genetically hardwired to perform specific functions and those alone, each developed and refined over millions of years of evolution. Once one of them is this damaged, it can't be replaced. Now that her vestibular system is damaged, Cheryl has as much chance of regaining her balance as a person whose retina has been damaged has of seeing again. But today all that is about to be challenged. She is wearing a construction hat with holes in the side and a device inside it called an accelerometer. Licking a thin plastic strip with small electrodes on it, she places it on her tongue. The accelerometer in the hat sends signals to the strip, and both are attached to a nearby computer. She laughs at the way she looks in the hat, "because if I don't laugh I will cry." This machine is one of Bach-y-Rita's bizarre-looking prototypes. It will replace her vestibular apparatus and send balance signals to her brain from her tongue. The hat may reverse Cheryl's current nightmare. In 1997 after a routine hysterectomy, Cheryl, then thirty-nine years old, got a postoperative infection and was given the antibiotic gentamicin. Excessive use of gentamicin is known to poison the inner ear structures and can be responsible for hearing loss (which Cheryl doesn't have), ringing in the ears (which she does), and devastation to the balance system. But because gentamicin is cheap and effective, it is still prescribed, though usually for only a brief period of time. Cheryl says she was given the drug way beyond the limit. And so she became one of a small tribe of gentamicin's casualties, known among themselves as Wobblers. Suddenly one day she discovered she couldn't stand without falling. She'd turn her head, and the whole room would move. She couldn't figure out if she or the walls were causing the movement. Finally she got to her feet by hanging on to the wall and reached for the phone to call her doctor. When she arrived at the hospital, the doctors gave her various tests to see if her vestibular function was working. They poured freezing-cold and warm water into her ears and tilted her on a table. When they asked her to stand with her eyes closed, she fell over. A doctor told her, "You have no vestibular function." The tests showed she had about 2 percent of the function left. "He was," she says, "so nonchalant. 'It looks like a side effect of the gentamicin.'" Here Cheryl gets emotional. "Why in the world wasn't I told about that? 'It's permanent,' he said. I was alone. My mother had taken me to the doctor, but she went off to get the car and was waiting for me outside the hospital. My mother asked, 'Is it going to be okay?' And I looked at her and said, 'It's permanent... this is never going to go away'" Because the link between Cheryl's vestibular apparatus and her visual system is damaged, her eyes can't follow a moving target smoothly. "Everything I see bounces like a bad amateur video," she says. "It's as though everything I look at seems made of Jell-O, and with each step I take, everything wiggles." Although she can't track moving objects with her eyes, her vision is all she has to tell her that she is upright. Our eyes help us know where we are in space by fixing on horizontal lines. Once when the lights went out, Cheryl immediately fell to the floor. But vision proves an unreliable crutch for her, because any kind of movement in front of her — even a person reaching out to her — exacerbates the falling feeling. Even zigzags on a carpet can topple her, by initiating a burst of false messages that make her think she's standing crookedly when she's not. She suffers mental fatigue, as well, from being on constant high alert. It takes a lot of brain power to maintain an upright position — brain power that is taken away from such mental functions as memory and the ability to calculate and reason. While Yuri is readying the computer for Cheryl, I ask to try the machine. I put on the construction worker's hat and slip into my mouth the plastic device with electrodes on it, called a tongue display. It is flat, no thicker than a stick of chewing gum. The accelerometer, or sensor, in the hat detects movement in two planes. As I nod my head, the movement is translated onto a map on the computer screen that permits the team to monitor it. The same map is projected onto a small array of 144 electrodes implanted in the plastic strip on my tongue. As I tilt forward, electric shocks that feel like champagne bubbles go off on the front of my tongue, telling me that I am bending forward. On the computer screen I can see where my head is. As I tilt back, I feel the champagne swirl in a gentle wave to the back of my tongue. The same happens when I tilt to the sides. Then I close my eyes and experiment with finding my way in space with my tongue. I soon forget that the sensory information is coming from my tongue and can read where I am in space. Cheryl takes the hat back; she keeps her balance by leaning against the table. "Let's begin," says Yuri, adjusting the controls. Cheryl puts on the hat and closes her eyes. She leans back from the table, keeping two fingers on it for contact. She doesn't fall, though she has no indication whatsoever of what is up and down except the swirling of the champagne bubbles over her tongue. She lifts her fingers from the table. She's not wobbling anymore. She starts to cry — the flood of tears that comes after a trauma; she can open up now that she has the hat on and feels safe. The first time she put on the hat, the sense of perpetual falling left her — for the first time in five years. Her goal today is to stand, free, for twenty minutes, with the hat on, trying to keep centered. For anyone — not to mention a Wobbler — to stand straight for twenty minutes requires the training and skill of a guard at Buckingham Palace. She looks peaceful. She makes minor corrections. The jerking has stopped, and the mysterious demons that seemed to be inside her, pushing her, shoving her, have vanished. Her brain is decoding signals from her artificial vestibular apparatus. For her, these moments of peace are a miracle — a neuroplastic miracle, because somehow these tingling sensations on her tongue, which normally make then way to the part of the brain called the sensory cortex — the thin layer on the surface of the brain that processes the sense of touch — are making their way, through a novel pathway in the brain, to the brain area that processes balance. "We are now working on getting this device small enough so that it is hidden in the mouth," says Bach-y-Rita, "like an orthodontist's mouth retainer. That's our goal. Then she, and anyone with this problem, will have a normal life restored. Someone like Cheryl should be able to wear the apparatus, talk, and eat without anyone knowing she has it. "But this isn't just going to affect people damaged by gentamicin," he continues. "There was an article in The New York Times yesterday on falls in the elderly. Old people are more frightened of falling than of being mugged, A third of the elderly fall, and because they fear falling, they stay home, don't use their limbs, and become more physically frail. But I think part of the problem is that the vestibular sense — just like hearing, taste, eyesight, and our other senses — starts to weaken as we age. This device will help them." "It's time," says Yuri, turning off the machine. Now comes the second neuroplastic marvel. Cheryl removes the tongue device and takes off the hat. She gives a big grin, stands free with her eyes closed, and doesn't fall. Then she opens her eyes and, still not touching the table, lifts one foot off the ground, so she's balancing on the other. "I love this guy," she says, and goes over and gives Bach-y-Rita a hug. She comes over to me. She's overflowing with emotion, overwhelmed by feeling the world under her feet again, and she gives me a hug too. "I feel anchored and solid. I don't have to think where my muscles are. I can actually think of other things." She returns to Yuri and gives him a kiss. "I have to emphasize why this is a miracle," says Yuri, who considers himself a data-driven skeptic. "She has almost no natural sensors. For the past twenty minutes we provided her with an artificial sensor. But the real miracle is what is happening now that we have removed the device, and she doesn't have either an artificial or a natural vestibular apparatus. We are awakening some kind of force inside her." The first time they tried the hat, Cheryl wore it for only a minute. They noticed that after she took it off, there was a "residual effect" that lasted about twenty seconds, a third of the time she wore the device. Then Cheryl wore the hat for two minutes and the residual effect lasted about forty seconds. Then they went up to about twenty minutes, expecting a residual effect of just under seven minutes. But instead of lasting a third of the time, it lasted triple the time, a full hour. Today, Bach-y-Rita says, they are experimenting to see if twenty more minutes on the device will lead to some kind of training effect, so that the residual effect will last even longer. Cheryl starts clowning and showing off. "I can walk like a woman again. That's probably not important to most people, but it means a lot that I don't have to walk with my feet wide apart now." She gets up on a chair and jumps off. She bends down to pick things up off the floor, to show she can right herself. "Last time I did this I was able to jump rope in the residual time." "What is amazing," says Yuri, "is that she doesn't just keep her posture. After some time on the device, she behaves almost normally. Balancing on a beam. Driving a car. It is the recovery of the vestibular function. When she moves her head, she can keep her focus on her target — the link between the visual and vestibular systems is also recovered." I look up, and Cheryl is dancing with Bach-y-Rita. She leads. How is it that Cheryl can dance and has returned to normal functioning without the machine? Bach-y-Rita thinks there are several reasons. For one, her damaged vestibular system is disorganized and "noisy," sending off random signals. Thus, noise from the damaged tissue blocks any signals sent by healthy tissue. The machine helps to reinforce the signals from her healthy tissues. He thinks the machine also helps recruit other pathways, which is where plasticity comes in. A brain system is made of many neuronal pathways, or neurons that are connected to one another and working together. If certain key pathways are blocked, then the brain uses older pathways to go around them. "I look at it this way," says Bach-y-Rita. "If you are driving from here to Milwaukee, and the main bridge goes out, first you are paralyzed. Then you take old secondary roads through the farmland. Then, as you use these roads more, you find shorter paths to use to get where you want to go, and you start to get there faster." These "secondary" neural pathways are "unmasked," or exposed, and, with use, strengthened. This "unmasking" is generally thought to be one of the main ways the plastic brain reorganizes itself. The fact that Cheryl is gradually lengthening the residual effect suggests that the unmasked pathway is getting stronger. Bach-y-Rita hopes that Cheryl, with training, will be able to continue extending the length of the residual effect. A few days later an e-mail for Bach-y-Rita arrives from Cheryl, her report from home about how long the residual time lasted. "Total residual time was: 3 hours, 20 minutes... The wobbling begins in my head — just like usual... I am having trouble finding words... Swimming feeling in my head. Tired, exhausted... Depressed." A painful Cinderella story. Coming down from normalcy is very hard. When it happens, she feels she has died, come to life, and then died again. On the other hand, three hours and twenty minutes after only twenty minutes on the machine is residual time ten times greater than the time on the device. She is the first Wobbler ever to have been treated, and even if the residual time never grows longer, she could now wear the device briefly four times a day and have a normal life. But there is good reason to expect more, since each session seems to be training her brain to extend the residual time. If this keeps up...... It did keep up. Over the next year Cheryl wore the device more frequently to get relief and build up her residual effect. Her residual effect progressed to multiple hours, to days, and then to four months. Now she does not use the device at all and no longer considers herself a Wobbler. In 1969, Nature, Europe's premier science journal, published a short article that had a distinctly sci-fi feel about it. Its lead author, Paul Bach-y-Rita, was both a basic scientist and a rehabilitation physician — a rare combination. The article described a device that enabled people who had been blind from birth to see. All had damaged retinas and had been considered completely untreatable. The Nature article was reported in The New York Times, Newsweek, and Life, but perhaps because the claim seemed so implausible, the device and its inventor soon slipped into relative obscurity. Accompanying the article was a picture of a bizarre-looking machine — a large old dentist's chair with a vibrating back, a tangle of wires, and bulky computers. The whole contraption, made of castaway parts combined with 1960s electronics, weighed four hundred pounds. A congenitally blind person — someone who had never had any experience of sight — sat in the chair, behind a large camera the size of those used in television studios at the time. He "scanned" a scene in front of him by turning hand cranks to move the camera, which sent electrical signals of the image to a computer that processed them. Then the electrical signals were conveyed to four hundred vibrating stimulators, arranged in rows on a metal plate attached to the inside of the chair back, so the stimulators rested against the blind subject's skin. The stimulators functioned like pixels vibrating for the dark part of a scene and holding still for the brighter shades. This "tactile-vision device," as it was called, enabled blind subjects to read, make out faces and shadows, and distinguish which objects were closer and which farther away. It allowed them to discover perspective and observe how objects seem to change shape depending upon the angle from which they were viewed. The six subjects of the experiment learned to recognize such objects as a telephone, even when it was partially obscured by a vase. This being the 1960s, they even learned to recognize a picture of the anorexic supermodel Twiggy. Everyone who used the relatively clunky tactile-vision device had a remarkable perceptual experience, as they went from having tactile sensations to "seeing" people and objects. With a little practice, the blind subjects began to experience the space in front of them as three-dimensional, even though the information entered from the two- dimensional array on their backs. If someone threw a ball toward the camera, the subject would automatically jump back to duck it. If the plate of vibrating stimulators was moved from their backs to their abdomens, subjects still accurately perceived the scene as happening in front of the camera. If tickled near the stimulators, they didn't confuse the tickle with a visual stimulus. Their mental perceptual experience took place not on the skin surface but in the world. And their perceptions were complex. With practice, subjects could move the camera around and say things like "That is Betty; she is wearing her hair down today and does not have her glasses on; her mouth is open, and she is moving her right hand from her left side to the back of her head," True, the resolution was often poor, but as Bach-y-Rita would explain, vision doesn't have to be perfect to be vision. "When we walk down a foggy street and see the outline of a building," he would ask, "are we seeing it any less for the lack of resolution? When we see something in black and white, are we not seeing it for lack of color?" This now-forgotten machine was one of the first and boldest applications of neuroplasticity — an attempt to use one sense to replace another — and it worked. Yet it was thought implausible and ignored because the scientific mind-set at the time assumed that the brain's structure is fixed, and that our senses, the avenues by which experience gets into our minds, are hardwired. This idea, which still has many adherents, is called "localizationism." It's closely related to the idea that the brain is like a complex machine, made up of parts, each of which performs a specific mental function and exists in a genetically predetermined or hardwired location — hence the name. A brain that is hardwired, and in which each mental function has a strict location, leaves little room for plasticity. The idea of the machinelike brain has inspired and guided neuro-science since it was first proposed in the seventeenth century, replacing more mystical notions about the soul and the body. Scientists, impressed by the discoveries of Galileo (1564-1642), who showed that the planets could be understood as inanimate bodies moved by mechanical forces, came to believe that all nature functioned as a large cosmic clock, subject to the laws of physics, and they began to explain individual living things, including our bodily organs, mechanistically, as though they too were machines. This idea that all nature was like a vast mechanism, and that our organs were machinelike, replaced the two-thousand-year-old Greek idea that viewed all nature as a vast living organism, and our bodily organs as anything but inanimate mechanisms. But the first great accomplishment of this new "mechanistic biology" was a brilliant and original achievement. William Harvey (1578-1657), who studied anatomy in Padua, Italy, where Galileo lectured, discovered how our blood circulates through our bodies and demonstrated that the heart functions like a pump, which is, of course, a simple machine. It soon seemed to many scientists that for an explanation to be scientific it had to be mechanistic — that is, subject to the mechanical laws of motion. Following Harvey, the French philosopher Rene Descartes (1596-1650) argued that the brain and nervous system also functioned like a pump. Our nerves were really tubes, he argued, that went from our limbs to the brain and back. He was the first person to theorize how reflexes work, proposing that when a person is touched on the skin, a fluidlike substance in the nerve tubes flows to the brain and is mechanically "reflected" back down the nerves to move the muscles. As crude as it sounds, he wasn't so far off. Scientists soon refined his primitive picture, arguing that not some fluid but an electric current moved through the nerves. Descartes's idea of the brain as a complex machine culminated in our current idea of the brain as a computer and in localizationism. Like a machine, the brain came to be seen as made of parts, each one in a preassigned location, each performing a single function, so that if one of those parts was damaged, nothing could be done to replace it; after all, machines don't grow new parts. Localizationism was applied to the senses as well, theorizing that each of our senses — sight, hearing, taste, touch, smell, balance — has a receptor cell that specializes in detecting one of the various forms of energy around us. When stimulated, these receptor cells send an electric signal along their nerve to a specific brain area that processes that sense. Most scientists believed that these brain areas were so specialized that one area could never do the work of another. Almost in isolation from his colleagues, Paul Bach-y-Rita rejected these localizationist claims. Our senses have an unexpectedly plastic nature, he discovered, and if one is damaged, another can sometimes take over for it, a process he calls "sensory substitution." He developed ways of triggering sensory substitution and devices that give us "supersenses." By discovering that the nervous system can adapt to seeing with cameras instead of retinas, Bach-y-Rita laid the groundwork for the greatest hope for the blind: retinal implants, which can be surgically inserted into the eye. Unlike most scientists, who stick to one field, Bach-y-Rita has become an expert in many — medicine, psychopharmacology, ocular neurophysiology (the study of eye muscle), visuall neurophysiology (the study of sight and the nervous system), and biomedical engineering. He follows ideas wherever they take him. He speaks five languages and has lived for extended periods in Italy, Germany, France, Mexico, Sweden, and throughout the United States. He has worked in the labs of major scientists and Nobel Prize winners, but he has never much cared what others thought and doesn't play the political games that many researchers do in order to get ahead. After becoming a physician, he gave up medicine and switched to basic research. He asked questions that seemed to defy common sense, such as, "Are eyes necessary for vision, or ears for hearing, tongues for tasting, noses for smelling?" And then, when he was forty-four years old, his mind ever restless, he switched back to medicine and began a medical residency, with its endless days and sleepless nights, in one of the dreariest specialties of all: rehabilitation medicine. His ambition was to turn an intellectual backwater into a science by applying to it what he had learned about plasticity. Bach-y-Rita is a completely unassuming man. He is partial to five-dollar suits and wears Salvation Army clothes whenever his wife lets him get away with it. He drives a rusty twelve-year-old car, his wife a new model Passat. He has a full head of thick, wavy gray hair, speaks softly and rapidly, has the darkish skin of a Mediterranean man of Spanish and Jewish ancestry, and appears a lot younger than his sixty-nine years. He's obviously cerebral but radiates a boyish warmth toward his wife, Esther, a Mexican of Mayan descent. He is used to being an outsider. He grew up in the Bronx, was four foot ten when he entered high school because of a mysterious disease that stunted his growth for eight years, and was twice given a preliminary diagnosis of leukemia. He was beaten up by the larger students every day and during those years developed an extraordinarily high pain threshold. When he was twelve, his appendix burst, and the mysterious disease, a rare form of chronic appendicitis, was properly diagnosed. He grew eight inches and won his first fight. We are driving through Madison, Wisconsin, his home when he's not in Mexico. He is devoid of pretension, and after many hours of our talking together, he lets only one even remotely self-congratulatory remark leave his lips. "I can connect anything to anything." He smiles. "We see with our brains, not with our eyes," he says. This claim runs counter to the commonsensical notion that we see with our eyes, hear with our ears, taste with our tongues, smell with our noses, and feel with our skin. Who would challenge such facts? But for Bach-y-Rita, our eyes merely sense changes in light energy; it is our brains that perceive and hence see. How a sensation enters the brain is not important to Bach-y-Rita. ''When a blind man uses a cane, he sweeps it back and forth, and has only one point, the tip, feeding him information through the skin receptors in the hand, Yet this sweeping allows him to sort out where the doorjamb is, or the chair, or distinguish a foot when he hits it, because it will give a little. Then he uses this information to guide himself to the chair to sit down. Though his hand sensors are where he gets the information and where the cane 'interfaces' with him, what he subjectively perceives is not the cane's pressure on his hand but the layout of the room: chairs, walls, feet, the three-dimensional space. The actual receptor surface in the hand becomes merely a relay for information, a data port. The receptor surface loses its identity in the process," Bach-y-Rita determined that skin and its touch receptors could substitute for a retina, because both the skin and the retina are two-dimensional sheets, covered with sensory receptors, that allow a "picture" to form on them. It's one thing to find a new data port, or way of getting sensations to the brain. But it's another for the brain to decode these skin sensations and turn them into pictures. To do that, the brain has to learn something new, and the part of the brain devoted to processing touch has to adapt to the new signals. This adaptability implies that the brain is plastic in the sense that it can reorganize its sensory-perceptual system. If the brain can reorganize itself, simple localizationism cannot be a correct image of the brain. At first even Bach-y-Rita was a localizationist, moved by its brilliant accomplishments. Serious localizationism was first proposed in 1861, when Paul Broca, a surgeon, had a stroke patient who lost the ability to speak and could utter only one word. No matter what he was asked, the poor man responded, "Tan, tan." When he died, Broca dissected his brain and found damaged tissue in the left frontal lobe. Skeptics doubted that speech could be localized to a single part of the brain until Broca showed them the injured tissue, then reported on other patients who had lost the ability to speak and had damage in the same location. That place came to be called "Broca's area" and was presumed to coordinate the movements of the muscles of the lips and tongue. Soon afterward another physician, Carl Wernicke, connected damage in another brain area farther back to a different problem: the inability to understand language. Wernicke proposed that the damaged area was responsible for the mental representations of words and comprehension. It came to be known as "Wernicke's area." Over the next hundred years localizationism became more specific as new research refined the brain map. Unfortunately, though, the case for localizationism was soon exaggerated. It went from being a series of intriguing correlations (observations that damage to specific brain areas led to the loss of specific mental functions) to a general theory that declared that every brain function had only one hardwired location — an idea summarized by the phrase "one function, one location," meaning that if a part was damaged, the brain could not reorganize itself or recover that lost function. A dark age for plasticity began, and any exceptions to the idea of "one function, one location" were ignored. In 1868 Jules Cotard studied children who had early massive brain disease, in which the left hemisphere (including Broca's area) wasted away. Yet these children could still speak normally. This meant that even if speech tended to be processed in the left hemisphere, as Broca claimed, the brain might be plastic enough to reorganize itself, if necessary. In 1876 Otto Soltmann removed the motor cortex from infant dogs and rabbits — the part of the brain thought to be responsible for movement — yet found they were still able to move. These findings were submerged in the wave of localizationist enthusiasm. Bach-y-Rita came to doubt localizationism while in Germany in the early 1960s. He had joined a team that was studying how vision worked by measuring with electrodes electrical discharge from the visual processing area of a cat's brain. The team fully expected that when they showed the cat an image, the electrode in its visual processing area would send off an electric spike, showing it was processing that image. And it did. But when the cat's paw was accidentally stroked, the visual area also fired, indicating that it was processing touch as well. And they found that the visual area was also active when the cat heard sounds. Bach-y-Rita began to think that the localizationist idea of "one function, one location" couldn't be right. The "visual" part of the cat's brain was processing at least two other functions, touch and sound. He began to conceive of much of the brain as "polysensory" — that its sensory areas were able to process signals from more than one sense. This can happen because all our sense receptors translate different kinds of energy from the external world, no matter what the source, into electrical patterns that are sent down our nerves. These electrical patterns are the universal language "spoken" inside the brain — there are no visual images, sounds, smells, or feelings moving inside our neurons. Bach-y-Rita realized that the areas that process these electrical impulses are far more homogeneous than neuroscientists appreciated, a belief that was reinforced when the neuroscientist Vernon Mountcastle discovered that the visual, auditory, and sensory cortices all have a similar six-layer processing structure. To Bach-y-Rita, this meant that any part of the cortex should be able to process whatever electrical signals were sent to it, and that our brain modules were not so specialized after all. Over the next few years Bach-y-Rita began to study all the exceptions to localizationism. With his knowledge of languages, he delved into the untranslated, older scientific literature and rediscovered scientific work done before the more rigid versions of localizationism had taken hold. He discovered the work of Marie-Jean-Pierre Flourens, who in the 1820s showed that the brain could reorganize itself. And he read the oft-quoted but seldom translated work of Broca in French and found that even Broca had not closed the door to plasticity as his followers had. The success of his tactile-vision machine further inspired Bach-y-Rita to reinvent his picture of the human brain. After all, it was not his machine that was the miracle, but the brain that was alive, changing, and adapting to new kinds of artificial signals. As part of the reorganization, he guessed that signals from the sense of touch (processed initially in the sensory cortex, near the top of the brain) were rerouted to the visual cortex at the back of the brain for further processing, which meant that any neuronal paths that ran from the skin to the visual cortex were undergoing development. Forty years ago, just when localization's empire had extended to its furthest reaches, Bach-y-Rita began his protest. He praised localization's accomplishments but argued that "a large body of evidence indicates that the brain demonstrates both motor and sensory plasticity." One of his papers was rejected for publication six times by journals, not because the evidence was disputed but because he dared to put the word "plasticity" in the title. After his Nature article came out, his beloved mentor, Ragnar Granit, who had received the Nobel Prize in physiology in 1965 for his work on the retina, and who had arranged for the publication of Bach-y-Rita's medical school thesis, invited him over for tea. Granit asked his wife to leave the room and, after praising Bach-y- Rita's work on the eye muscles, asked him — for his own good — why he was wasting his time with "that adult toy." Yet Bach-y-Rita persisted and began to lay out, in a series of books and several hundred articles, the evidence for brain plasticity and to develop a theory to explain how it might work. Bach-y-Rita's deepest interest became explaining plasticity, but he continued to invent sensory-substitution devices. He worked with engineers to shrink the dentist-chair-computer-camera device for the blind. The clumsy, heavy plate of vibrating stimulators that had been attached to the back has now been replaced by a paper-thin strip of plastic covered with electrodes, the diameter of a silver dollar, that is slipped onto the tongue, The tongue is what he calls the ideal "brain-machine interface," an excellent entry point to the brain because it has no insensitive layer of dead skin on it. The computer too has shrunk radically, and the camera that was once the size of a suitcase now can be worn strapped to the frame of eyeglasses. He has been working on other sensory-substitution inventions as well. He received NASA funding to develop an electronic "feeling" glove for astronauts in space. Existing space gloves were so thick that it was hard for the astronauts to feel small objects or perform delicate movements. So on the outside of the glove he put electric sensors that relayed electrical signals to the hand. Then he took what he learned making the glove and invented one to help people with leprosy, whose illness mutilates the skin and destroys peripheral nerves so that the lepers lose sensation in their hands. This glove, like the astronaut's glove, had sensors on the outside, and it sent its signals to a healthy part of the skin — away from the diseased hands — where the nerves were unaffected. That healthy skin became the portal of entry for hand sensations. He then began work on a glove that would allow blind people to read computer screens, and he even has a project for a condom that he hopes will allow spinal cord injury victims who have no feeling in their penises to have orgasms. It is based on the premise that sexual excitement, like other sensory experiences, is "in the brain," so the sensations of sexual movement, picked up by sensors on the condom, can be translated into electrical impulses that can then be transmitted to the part of the brain that processes sexual excitement. Other potential uses of his work include giving people "supersenses," such as infrared or night vision. He has developed a device for the Navy SEALs that helps them sense how their bodies are oriented underwater, and another, successfully tested in France, that tells surgeons the exact position of a scalpel by sending signals from an electronic sensor attached to the scalpel to a small device attached to their tongues and to their brains. The origin of Bach-y-Rita's understanding of brain rehabilitation lies in the dramatic recovery of his own father, the Catalan poet and scholar Pedro Bach-y- Rita, after a disabling stroke. In 1959 Pedro, then a sixty-five-year-old widower, had a stroke that paralyzed his face and half of his body and left him unable to speak. George, Paul's brother, now a psychiatrist in California, was told that his father had no hope of recovery and would have to go into an institution. Instead, George, then a medical student in Mexico, brought his paralyzed father from New York, where he lived, back to Mexico to live with him. At first he tried to arrange rehabilitation for his father at the American British Hospital, which offered only a typical four-week rehab, as nobody believed the brain could benefit from extended treatment. After four weeks his father was nowhere near better. He was still helpless and needed to be lifted onto and off the toilet and showered, which George did with the help of the gardener. "Fortunately, he was a little man, a hundred and eighteen pounds, and we could manage him," says George. George knew nothing about rehabilitation, and his ignorance turned out to be a godsend, because he succeeded by breaking all its current rules, unencumbered by pessimistic theories. "I decided that instead of teaching my father to walk, I was going to teach him first to crawl. I said, 'You started off crawling, you are going to have to crawl again for a while.' We got kneepads for him. At first we held him on all fours, but his arms and legs didn't hold him very well, so it was a struggle." As soon as Pedro could support himself somewhat, George then got him to crawl with his weak shoulder and arm supported by a wall. "That crawling beside the wall went on for months. After that I even had him practicing in the garden, which led to problems with the neighbors, who were saying it wasn't nice, it was unseemly, to be making the professor crawl like a dog. The only model I had was how babies learn. So we played games on the floor, with me rolling marbles, and him having to catch them. Or we'd throw coins on the floor, and he'd have to try and pick them up with his weak right hand. Everything we tried involved turning normal life experiences into exercises. We turned washing pots into an exercise. He'd hold the pot with his good hand and make his weak hand — it had little control and made spastic jerking movements — go round and round, fifteen minutes clockwise, fifteen minutes counterclockwise. The circumference of the pot kept his hand contained. There were steps, each one overlapping with the one before, and little by little he got better. After a while he helped to design the steps. He wanted to get to the point where he could sit down and eat with me and the other medical students." The regime took many hours every day, but gradually Pedro went from crawling, to moving on his knees, to standing, to walking, Pedro struggled with his speech on his own, and after about three months there were signs it too was coming back. After a number of months he wanted to resume his writing. He would sit in front of the typewriter, his middle finger over the desired key, then drop his whole arm to strike it. When he had mastered that, he would drop just the wrist, and finally the fingers, one at a time. Eventually he learned to type normally again. At the end of a year his recovery was complete enough for Pedro, now sixty-eight, to start full-time teaching again at City College in New York. He loved it and worked until he retired at seventy. Then he got another teaching job at San Francisco State, remarried, and kept working, hiking, and traveling. He was active for seven more years after his stroke. On a visit to friends in Bogota, Colombia, he went climbing high in the mountains. At nine thousand feet he had a heart attack and died shortly thereafter. He was seventy-two. I asked George if he understood how unusual this recovery was so long after his father's stroke and whether he thought at the time that the recovery might have been the result of brain plasticity. "I just saw it in terms of taking care of Papa. But Paul, in subsequent years, talked about it in terms of neuroplasticity. Not right away, though. It wasn't until after our father died." Pedro's body was brought to San Francisco, where Paul was working. It was 1965, and in those days, before brain scans, autopsies were routine because they were one way doctors could learn about brain diseases, and about why a patient died. Paul asked Dr. Mary Jane Aguilar to perform the autopsy. "A few days later Mary Jane called me and said, 'Paul, come down. I've got something to show you.' When I got to the old Stanford Hospital, there, spread out on the table, were slices of my father's brain on slides." He was speechless. "I was feeling revulsion, but I could also see Mary Jane's excitement, because what the slides showed was that my father had had a huge lesion from his stroke and that it had never healed, even though he recovered all those functions. I freaked out. I got numb. I was thinking, 'Look at all this damage he has.' And she said, 'How can you recover with all this damage?'" When he looked closely, Paul saw that his father's seven-year-old lesion was mainly in the brain stem — the part of the brain closest to the spinal cord — and that other major brain centers in the cortex that control movement had been destroyed by the stroke as well. Ninety-seven percent of the nerves that run from the cerebral cortex to the spine were destroyed — catastrophic damage that had caused his paralysis. "I knew that meant that somehow his brain had totally reorganized itself with the work he did with George. We didn't know how remarkable his recovery was until that moment, because we had no idea of the extent of his lesion, since there were no brain scans in those days. When people did recover, we tended to assume that there really hadn't been much damage in the first place. She wanted me to be a coauthor on the paper she wrote about his case. I couldn't." His father's story was firsthand evidence that a "late" recovery could occur even with a massive lesion in an elderly person. But after examining that lesion and reviewing the literature, Paul found more evidence that the brain can reorganize itself to recover functions after devastating strokes, discovering that in 1915 an American psychologist, Shepherd Ivory Franz, had shown that patients who had been paralyzed for twenty years were capable of making late recoveries with brain-stimulating exercises. His father's "late recovery" triggered a career change for Bach-y-Rita. At forty- four, he went back to practicing medicine and did residencies in neurology and rehabilitation medicine. He understood that for patients to recover they needed to be motivated, as his father had been, with exercises that closely approximated real-life activities. He turned his attention to treating strokes, focusing on "late rehabilitation)" helping people overcome major neurological problems years after they'd begun, and developing computer video games to train stroke patients to move their arms again. And he began to integrate what he knew about plasticity into exercise design. Traditional rehabilitation exercises typically ended after a few weeks, when a patient stopped improving, or plateaued, and doctors lost the motivation to continue. But Bach-y-Rita, based on his knowledge of nerve growth, began to argue that these learning plateaus were temporary — part of a plasticity- based learning cycle — in which stages of learning are followed by periods of consolidation. Though there was no apparent progress in the consolidation stage, biological changes were happening internally, as new skills became more automatic and refined. Bach-y-Rita developed a program for people with damaged facial motor nerves, who could not move their facial muscles and so couldn't close their eyes, speak properly, or express emotion, making them look like monstrous automatons. Bach-y-Rita had one of the "extra" nerves that normally goes to the tongue surgically attached to a patient's facial muscles. Then he developed a program of brain exercises to train the "tongue nerve" (and particularly the part of the brain that controls it) to act like a facial nerve. These patients learned to express normal facial emotions, speak, and close their eyes — one more instance of Bach- y-Rita's ability to "connect anything to anything." Thirty-three years after Bach-y-Rita's Nature article, scientists using the small modern version of his tactile-vision machine have put patients under brain scans and confirmed that the tactile images that enter patients through their tongues are indeed processed in their brains' visual cortex. All reasonable doubt that the senses can be rewired was recently put to rest in one of the most amazing plasticity experiments of our time. It involved rewiring not touch and vision pathways, as Bach-y-Rita had done, but those for hearing and vision — literally. Mriganka Sur, a neuroscientist, surgically rewired the brain of a very young ferret. Normally the optic nerves run from the eyes to the visual cortex, but Sur surgically redirected the optic nerves from the ferret's visual to its auditory (hearing) cortex and discovered that the ferret learned to see. Using electrodes inserted into the ferret's brain, Sur proved that when the ferret was seeing, the neurons in its auditory cortex were firing and doing the visual processing. The auditory cortex, as plastic as Bach-y-Rita had always imagined, had reorganized itself, so that it had the structure of the visual cortex. Though the ferrets that had this surgery did not have 20/20 vision, they had about a third of that, or 20/60 — no worse than some people who wear eyeglasses. Till recently, such transformations would have seemed utterly inexplicable. But Bach-y-Rita, by showing that our brains are more flexible than localizationism admits, has helped to invent a more accurate view of the brain that allows for such changes. Before he did this work, it was acceptable to say, as most neuroscientists do, that we have a "visual cortex" in our occipital lobe that processes vision, and an "auditory cortex" in our temporal lobe that processes hearing. From Bach-y-Rita we have learned that the matter is more complicated and that these areas of the brain are plastic processors, connected to each other and capable of processing an unexpected variety of input. Cheryl has not been the only one to benefit from Bach-y-Rita's strange hat. The team has since used the device to train fifty more patients to improve their balance and walking. Some had the same damage Cheryl had; others have had brain trauma, stroke, or Parkinson's disease. Paul Bach-y-Rita's importance lies in his being the first of his generation of neuroscientists both to understand that the brain is plastic and to apply this knowledge in a practical way to ease human suffering. Implicit in all his work is the idea that we are all born with a far more adaptable, all-purpose, opportunistic brain than we have understood. When Cheryl's brain developed a renewed vestibular sense — or blind subjects' brains developed new paths as they learned to recognize objects, perspective, or movement — these changes were not the mysterious exception to the rule but the rule: the sensory cortex is plastic and adaptable. When Cheryl's brain learned to respond to the artificial receptor that replaced her damaged one, it was not doing anything out of the ordinary. Recently Bach-y- Rita's work has inspired cognitive scientist Andy Clark to wittily argue that we are "natural-born cyborgs," meaning that brain plasticity allows us to attach ourselves to machines, such as computers and electronic tools, quite naturally. But our brains also restructure themselves in response to input from the simplest tools too, such as a blind man's cane. Plasticity has been, after all, a property inherent in the brain since prehistoric times. The brain is a far more open system than we ever imagined, and nature has gone very far to help us perceive and take in the world around us. It has given us a brain that survives in a changing world by changing itself. Chapter 2 Building Herself a Better Brain A Woman Labeled "Retarded" Discovers How to Heal Herself The scientists who make important discoveries about the brain are often those whose own brains are extraordinary, working on those whose brains are damaged. It is rare that the person who makes an important discovery is the one with the defect, but there are some exceptions. Barbara Arrowsmith Young is one of these. "Asymmetry" is the word that best describes her mind when she was a schoolgirl. Born in Toronto in 1951 and raised in Peterborough, Ontario, Barbara had areas of brilliance as a child — her auditory and visual memory both tested in the ninety-ninth percentile. Her frontal lobes were remarkably developed, giving her a driven, dogged quality. But her brain was "asymmetrical," meaning that these exceptional abilities coexisted with areas of retardation. This asymmetry left its chaotic handwriting on her body as well. Her mother made a joke of it. "The obstetrician must have yanked you out by your right leg," which was longer than her left, causing her pelvis to shift. Her right arm never straightened, her right side was larger than her left, her left eye less alert, Her spine was asymmetrical and twisted with scoliosis. She had a confusing assortment of serious learning disabilities. The area of her brain devoted to speech, Broca's area, was not working properly, so she had trouble pronouncing words. She also lacked the capacity for spatial reasoning. When we wish to move our bodies in space, we use spatial reasoning to construct an imaginary pathway in our heads before executing our movements. Spatial reasoning is important for a baby crawling, a dentist drilling a tooth, a hockey player planning his moves. One day when Barbara was three she decided to play matador and bull. She was the bull, and the car in the driveway was the matador's cape. She charged, thinking she would swerve and avoid it, but she misjudged the space and ran into the car, ripping her head open. Her mother declared she would be surprised if Barbara lived another year. Spatial reasoning is also necessary for forming a mental map of where things are. We use this kind of reasoning to organize our desks or remember where we have left our keys. Barbara lost everything all the time. With no mental map of things in space, out of sight was literally out of mind, so she became a "pile person" and had to keep everything she was playing with or working on in front of her in piles, and her closets and dressers open. Outdoors she was always getting lost. She also had a "kinesthetic" problem. Kinesthetic perception allows us to be aware of where our body or limbs are in space, enabling us to control and coordinate our movements. It also helps us recognize objects by touch. But Barbara could never tell how far her arms or legs had moved on her left side. Though a tomboy in spirit, she was clumsy. She couldn't hold a cup of juice in her left hand without spilling it. She frequently tripped or stumbled. Stairs were treacherous. She also had a decreased sense of touch on her left and was always bruising herself on that side. When she eventually learned to drive, she kept denting the left side of the car. She had a visual disability as well. Her span of vision was so narrow that when she looked at a page of writing, she could take in only a few letters at a time. But these were not her most debilitating problems. Because the part of her brain that helps to understand the relationships between symbols wasn't functioning normally, she had trouble understanding grammar, math concepts, logic, and cause and effect. She couldn't distinguish between "the father's brother" and "the brother's father." The double negative was impossible for her to decipher. She couldn't read a clock because she couldn't understand the relationship between the hands. She literally couldn't tell her left hand from her right, not only because she lacked a spatial map but because she couldn't understand the relationship between "left" and "right." Only with extraordinary mental effort and constant repetition could she learn to relate symbols to one another. She reversed b, d, q, and p, read "was" as "saw," and read and wrote from right to left, a disability called mirror writing. She was right-handed, but because she wrote from right to left, she smeared all her work. Her teachers thought she was being obstreperous. Because she was dyslexic, she made reading errors that cost her dearly. Her brothers kept sulfuric acid for experiments in her old nose-drops bottle. Once when she decided to treat herself for sniffles, Barbara misread the new label they had written. Lying in bed with acid running into her sinuses, she was too ashamed to tell her mother of yet another mishap. Unable to understand cause and effect, she did odd things socially because she couldn't connect behavior with its consequences. In kindergarten she couldn't understand why, if her brothers were in the same school, she couldn't leave her class and visit them in theirs whenever she wanted. She could memorize math procedures but couldn't understand math concepts. She could recall that five times five equals twenty-five but couldn't understand why. Her teachers responded by giving her extra drills, and her father spent hours tutoring her, to no avail. Her mother held up flash cards with simple math problems on them. Because Barbara couldn't figure them out, she found a place to sit where the sun made the paper translucent, so she could read the answers on the back. But the attempts at remediation didn't get at the root of the problem; they just made it more agonizing. Wanting desperately to do well, she got through elementary school by memorizing during lunch hours and after school. In high school her performance was extremely erratic. She learned to use her memory to cover her deficits and with practice could remember pages of facts. Before tests she prayed they would be fact-based, knowing she could score 100; if they were based on understanding relationships, she would probably score in the low teens. Barbara understood nothing in real time, only after the fact, in lag time. Because she did not understand what was happening around her while it was occurring, she spent hours reviewing the past, to make its confusing fragments come together and become comprehensible. She had to replay simple conversations, movie dialogue, and song lyrics twenty times over in her head because by the time she got to the end of a sentence, she could not recall what the beginning meant. Her emotional development suffered. Because she had trouble with logic, she could not pick up inconsistencies when listening to smooth talkers and so she was never sure whom to trust. Friendships were difficult, and she could not have more than one relationship at a time. But what plagued her most was the chronic doubt and uncertainty that she felt about everything. She sensed meaning everywhere but could never verify it. Her motto was "I don't get it." She told herself, "I live in a fog, and the world is no more solid than cotton candy." Like many children with serious learning disabilities, she began to think she might be crazy. Barbara grew up in a time when little help was available. "In the 1950s, in a small town like Peterborough, you didn't talk about these things," she says. "The attitude was, you either make it or you don't. There were no specialized teachers, no visits to medical specialists or psychologists. The term 'learning disabilities' wouldn't be widely used for another two decades. My grade- one teacher told my parents I had 'a mental block' and I wouldn't ever learn the way others did. That was as specific as it got. You were either bright, average, slow, or mentally retarded." If you were mentally retarded, you were placed in "opportunity classes." But that was not the place for a girl with a brilliant memory who could ace vocabulary tests. Barbara's childhood friend Donald Frost, now a sculptor, says, "She was under incredible academic pressure. The whole Young family were high achievers. Her father, Jack, was an electrical engineer and inventor with thirty-four patents for Canadian General Electric. If you could pull Jack from a book for dinner, it was a miracle. Her mother, Mary, had the attitude: 'You will succeed; there is no doubt,' and 'If you have a problem, fix it.' Barbara was always incredibly sensitive, warm, and caring," Frost continues, "but she hid her problems well. It was hush- hush. In the postwar years there was a sense of integrity that meant you didn't draw attention to your disabilities any more than you would to your pimples." Barbara gravitated toward the study of child development, hop-ins somehow to sort things out for herself. As an undergraduate at the University of Guelph, her great mental disparities were again apparent. But fortunately her teachers saw that she had a remarkable ability to pick up nonverbal cues in the child- observation laboratory, and she was asked to teach the course. She felt there must have been some mistake. Then she was accepted into graduate school at the Ontario Institute for Studies in Education (OISE). Most students read a research paper once or twice, but typically Barbara had to read one twenty times as well as many of its sources to get even a fleeting sense of its meaning, She survived on four hours of sleep a night. Because Barbara was brilliant in so many ways, and so adept at child observation, her teachers in graduate school had trouble believing she was disabled. It was Joshua Cohen, another gifted but learning-disabled student at OISE, who first understood. He ran a small clinic for learning-disabled kids that used the standard treatment, "compensations," based on the accepted theory of the time; once brain cells die or fail to develop, they cannot be restored. Compensations work around the problem. People with trouble reading listen to audiotapes. Those who are "slow" are given more time on tests. Those who have trouble following an argument are told to color-code the main points. Joshua designed a compensation program for Barbara, but she found it too time-consuming. Moreover, her thesis, a study of learning-disabled children treated with compensations at the OISE clinic, showed that most of them were not really improving. And she herself had so many deficits that it was sometimes hard to find healthy functions that could work around her deficits. Because she had had such success developing her memory, she told Joshua she thought there must be a better way. One day Joshua suggested she look into some books by Aleksandr Luria that he'd been reading. She tackled them, going over the difficult passages countless times, especially a section in Luria's Basic Problems of Neurolinguistics about people with strokes or wounds who had trouble with grammar, logic, and reading clocks. Luria, born in 1902, came of age in revolutionary Russia. He was deeply interested in psychoanalysis, corresponded with Freud, and wrote papers on the psychoanalytic technique of "free association," in which patients say everything that comes to mind. His goal was to develop objective methods to assess Freudian ideas. While still in his twenties, he invented the prototype of the lie detector. When the Great Purges of the Stalin era began, psychoanalysis became scientianon grata, and Luria was denounced. He delivered a public recantation, admitting to having made certain "ideological mistakes." Then, to remove himself from view, he went to medical school. But he had not totally finished with psychoanalysis. Without calling attention to his work, he integrated aspects of the psycho-analytic method and of psychology into neurology, becoming the founder of neuropsychology. His case histories, instead of being brief vignettes focused on symptoms, described his patients at length. As Oliver Sacks wrote, "Luria's case histories, indeed, can only be compared to Freud's in their precision, their vitality, their wealth and depth of detail." One of Luria's books, The Man with a Shattered World, was the summary of, and commentary on, the diary of a patient with a very peculiar condition. At the end of May 1943 Comrade Lyova Zazetsky, a man who seemed like a boy, came to Luria's office in the rehabilitation hospital where he was working. Zazetsky was a young Russian lieutenant who had just been injured in the battle of Smolensk, where poorly equipped Russians had been thrown against the invading Nazi war machine. He had sustained a bullet wound to the head, with massive damage on the left side, deep inside his brain. For a long time he lay in a coma. When Zazetsky awoke, his symptoms were very odd. The shrapnel had lodged in the part of the brain that helped him understand relationships between symbols. He could no longer understand logic, cause and effect, or spatial relationships. He couldn't distinguish his left from his right. He couldn't understand the elements of grammar dealing with relationships. Prepositions such as "in," "out," "before," "after," "with," and 'without" had become meaningless to him. He couldn't comprehend a whole word, understand a whole sentence, or recall a complete memory because doing any of those things would require relating symbols. He could grasp only fleeting fragments. Yet his frontal lobes — which allowed him to seek out what is relevant and to plan, strategize, form intentions, and pursue them — were spared, so he had the capacity to recognize his defects, and the wish to overcome them, Though he could not read, which is largely a perceptual activity, he could write, because it is an intentional one. He began a fragmentary diary he called I'll Fight On that swelled to three thousand pages. "I was killed March 2, 1943," he wrote, "but because of some vital power of my organism, I miraculously remained alive." Over thirty years Luria observed him and reflected on the way Zazetsky's wound affected his mental activities, He would witness Zazetsky's relentless fight "to live, not merely exist." Reading Zazetsky's diary, Barbara thought "He is describing my life." "I knew what the word? 'mother' and 'daughter' meant but not the expression 'mother's daughter,'" Zazetsky wrote. "The expressions 'mother's daughter' and 'daughter's mother' sounded just the same to me. I also had trouble with expressions like 'Is an elephant bigger than a fly?' All I could figure out was that a fly was small and an elephant is big, but I didn't understand the words 'bigger' and 'smaller.'" While watching a film, Zazetsky wrote, "before I've had a chance to figure out what the actors are saying, a new scene begins." Luria began to make sense of the problem. Zazetsky's bullet had lodged in the left hemisphere, at the junction of three major perceptual areas where the temporal lobe (which normally processes sound and language), the occipital lobe (which normally processes visual images), and the parietal lobe (which normally processes spatial relationships and integrates information from different senses) meet. At this junction perceptual input from those three areas is brought together and associated. While Zazetsky could perceive properly, Luria realized he could not relate his different perceptions, or parts of things to wholes. Most important, he had great difficulty relating a number of symbols to one another, as we normally do when we think with words. Thus Zazetsky often spoke in malapropisms. It was as though he didn't have a large enough net to catch and hold words and their meanings, and he often could not relate words to their meanings or definitions. He lived with fragments and wrote, 'I'm in a fog all the time... All that flashes through my mind are images.. hazy visions that suddenly appear and just as suddenly disappear... I simply can't understand or remember what these mean." For the first time, Barbara understood that her main brain deficit had an address. But Luria did not provide the one thing she needed: a treatment. When she realized how impaired she really was, she found herself more exhausted and depressed and thought she could not go on this way. On subway platforms she looked for a spot from which to jump for maximum impact. It was at this point in her life, while she was twenty-eight and still in graduate school, that a paper came across her desk. Mark Roseneig of the University of California at Berkeley had studied rats in stimulating and nonstimulating environments, and in postmortem exams he found that the brains of the stimulated rats had more neurotransmitters, were heavier, and had better blood supply than those from the less stimulating environments. He was one of the first scientists to demonstrate neuroplasticity by showing that activity could produce changes in the structure of the brain. For Barbara, lightning struck. Rosenzweig had shown that the brain could be modified. Though many doubted it, to her this meant that compensation might not be the only answer. Her own breakthrough would be to link Rosenzweig's and Luria's research. She isolated herself and began toiling to the point of exhaustion, week after week — with only brief breaks for sleep — at mental exercises she designed, though she had no guarantee they would lead anywhere. Instead of practicing compensation, she exercised her most weakened function — relating a number of symbols to each other, One exercise involved reading hundreds of cards picturing clock faces showing different times. She had Joshua Cohen write the correct time on the backs. She shuffled the cards so she couldn't memorize the answers. She turned up a card, attempted to tell the time, checked the answer, then moved on to the next card as fast as she could. When she couldn't get the time right, she'd spend hours with a real clock, turning the hands slowly, trying to understand why, at 2:45, the hour hand was three-quarters of the way toward the three. When she finally started to get the answers, she added hands for seconds and sixtieths of a second. At the end of many exhausting weeks, not only could she read clocks faster than normal people, but she noticed improvements in her other difficulties relating to symbols and began for the first time to grasp grammar, math, and logic. Most important, she could understand what people were saying as they said it. For the first time in her life, she began to live in real time. Spurred on by her initial success, she designed exercises for her other disabilities — her difficulties with space, her trouble with knowing where her limbs were, and her visual disabilities — and brought them up to average level. Barbara and Joshua Cohen married, and in 1980 they opened the Arrowsmith School in Toronto. They did research together, and Barbara continued to develop brain exercises and to run the school from day to day. Eventually they parted, and Joshua died in 2000. Because so few others knew about or accepted neuroplasticity or believed that the brain might be exercised as though it were a muscle, there was seldom any context in which to understand her work. She was viewed by some critics as making claims — that learning disabilities were treatable — that couldn't be substantiated. But far from being plagued by uncertainty, she continued to design exercises for the brain areas and functions most commonly weakened in those with learning disabilities. In these years before high-tech brain scans were available, she relied on Luria's work to understand which areas or the brain commonly processed which mental functions. Luria had formed his own map of the brain by working with patients like Zazetsky. He observed where a soldier's wound had occurred and related this location to the mental functions lost. Barbara found that learning disorders were often milder versions of the thinking deficits seen in Luria's patients. Applicants to the Arrowsmith School — children and adults alike — undergo up to forty hours of assessments, designed to determine precisely which brain functions are weak and whether they might be helped. Accepted students, many of whom were distracted in regular schools, sit quietly working at their computers. Some, diagnosed with attention-deficit as well as learning disorders, were on Ritalin when they entered the school. As their exercises progress, some can come off medication, because their attention problems are secondary to their underlying learning disorders. At the school, children who, like Barbara, had been unable to read a clock now work at computer exercises reading mind-numbingly complex ten-handed clocks (with hands not only for minutes, hours, and seconds but also for other time divisions, such as days, months, years) in mere seconds. They sit quietly, with intense concentration, until they get enough answers right to progress to the nest level, when they shriek out a loud "Yes!" and their computer screen lights up to congratulate them. By the time they finish, they can read clocks far more complex than those any "normal" person can read. At other tables children are studying Urdu and Persian letters to strengthen their visual memories. The shapes of these letters are unfamiliar, and the brain exercise requires the students to learn to recognize these alien shapes quickly. Other children, like little pirates, wear eye patches on their left eyes and diligently trace intricate lines, squiggles, and Chinese letters with pens. The eye patch forces visual input into the right eye, then to the side of the brain where they have a problem. These children are not simply learning to write better. Most of them come with three related problems: trouble speaking in a smooth, flowing way, writing neatly, and reading. Barbara, following Luria, believes that all three difficulties are caused by a weakness in the brain function that normally helps us to coordinate and string together a number of movements when we perform these tasks. When we speak, our brain converts a sequence of symbols — the letters and words of the thought — into a sequence of movements made by our tongue and lip muscles. Barbara believes, again following Luria, that the part of the brain that strings these movements together is the left premotor cortex of the brain. I referred several people with a weakness in this brain function to the school. One boy with this problem was always frustrated, because his thoughts came faster than he could turn them into speech, and he would often leave out chunks of information, have trouble finding words, and ramble. He was a very social person yet could not express himself and so remained silent much of the time. When he was asked a question in class, he often knew the answer but took such a painfully long time to get it out that he appeared much less intelligent than he was, and he began to doubt himself. When we write a thought, our brain converts the words — which are symbols — into movements of the fingers and hands. The same boy had very jerky writing because his processing capacity for converting symbols into movements was easily overloaded, so he had to write with many separate, small movements instead of long, flowing ones. Even though he had been taught cursive writing, he preferred to print. (As adults, people with this problem can often be identified because they prefer to print or type. When we print, we make each letter separately, with just a few pen movements, which is less demanding on the brain. In cursive we write several letters at a time, and the brain must process more complex movements.) Writing was especially painful for the boy, since he often knew the right answers on tests but wrote so slowly that he couldn't get them all down. Or he would think of one word, letter, or number but write another. These children are often accused of being careless, but actually their over-loaded brains fire the wrong motor movements. Students with this disability also have reading problems. Normally when we read, the brain reads part of a sentence, then directs the eyes to move the right distance across the page to take in the next part of the sentence, requiring an ongoing sequence of precise eye movements. The boy's reading was very slow because he skipped words, lost his place, and then lost his concentration. Reading was overwhelming and exhausting. On exams he would often misread the question, and when he tried to proofread his answers, he'd skip whole sections. At the Arrowsmith School this boy's brain exercises involved tracing complex lines to stimulate his neurons in the weakened pre-motor area. Barbara has found that tracing exercises improve children in all three areas — speaking, writing, and reading. By the time the boy graduated, he read above grade level and could read for pleasure for the first time. He spoke more spontaneously in longer, fuller sentences, and his writing improved. At the school some students listen to CDs and memorize poems to improve their weak auditory memories. Such children often forget instructions and are thought to be irresponsible or lazy, when in fact they have a brain difficulty. Whereas the average person can remember seven unrelated items (such as a seven-digit phone number), these people can remember only two or three. Some take notes compulsively, so they won t forget. In severe cases, they can't follow a song lyric from beginning to end, and they get so overloaded they just tune out. Some have difficulty remembering not only spoken language but even their own thoughts, because thinking with language is slow. This deficit can be treated with exercises in rote memorizing. Barbara has also developed brain exercises for children who are socially clumsy because they have a weakness in the brain function that would allow them to read nonverbal cues. Other exercises are for those who have frontal lobe deficits and who are impulsive or have problems planning, developing strategies, sorting out what is relevant, forming goals, and sticking to them, They often appear disorganized, flighty, and unable to learn from their mistakes. Barbara believes that many people labeled "hysterical" or "antisocial" have weaknesses in this area. The brain exercises are life-transforming. One American graduate told me that when he came to the school at thirteen, his math and reading skills were still at a third-grade level. He had been told after neuropsychological testing at Tufts University that he would never improve. His mother had tried him in ten different schools for students with learning disabilities, but none had helped. After three years at Arrowsmith, he was reading and doing math at a tenth-grade level. Now he has graduated from college and works in venture capital. Another student came to Arrowsmith at sixteen reading at a first-grade level. His parents, both teachers, had tried all the standard compensation techniques. After fourteen months at Arrowsmith he is reading at a seventh-grade level. We all have some weak brain functions, and such neuroplasticity-based techniques have great potential to help almost everyone. Our weak spots can have a profound effect on our professional success, since most careers require the use of multiple brain functions. Barbara used brain exercises to rescue a talented artist who had a first-rate drawing ability and sense of color but a weak ability to recognize the shape of objects. (The ability to recognize shapes depends on a brain function quite different from those functions required for drawing or seeing color; it is the same skill that allows some people to excel at games like Where's Waldo? Women are often better at it at than men, which is why men seem to have more difficulty finding things in the refrigerator.) Barbara also helped a lawyer, a promising litigator who, because of a Broca's area pronunciation deficit, spoke poorly in court. Since expending the extra mental effort to support a weak area seems to divert resources from strong areas, a person with a Broca's problem may also find it harder to think while talking. After practicing brain exercises focused on Broca's area, the lawyer went on to a successful courtroom career. The Arrowsmith approach, and the use of brain exercises generally, has major implications for education. Clearly many children would benefit from a brain- area-based assessment to identify their weakened functions and a program to strengthen them — a far more productive approach than tutoring that simply repeats a lesson and leads to endless frustration. When "weak links in the chain" are strengthened, people gain access to skills whose development was formerly blocked, and they feel enormously liberated. A patient of mine, before he did the brain exercises, had a sense that he was very bright but could not make full use of his intelligence. For a long time I mistakenly thought his problems were based primarily on psychological conflicts, such as a fear of competition, and buried conflicts about surpassing his parents and siblings. Such conflicts did exist and did hold him back. But I came to see that his conflict about learning — his wish to avoid it — was based mostly on years of frustration and on a very legitimate fear of failure based on his brain's limits. Once he was liberated from his difficulties by Arrowsmith's exercises, his innate love of learning emerged full force. The irony of this new discovery is that for hundreds of years educators did seem to sense that children's brains had to be built up through exercises of increasing difficulty that strengthened brain functions. Up through the nineteenth and early twentieth centuries a classical education often included rote memorization of long poems in foreign languages, which strengthened the auditory memory (hence thinking in language) and an almost fanatical attention to handwriting, which probably helped strengthen motor capacities and thus not only helped handwriting but added speed and fluency to reading and speaking. Often a great deal of attention was paid to exact elocution and to perfecting the pronunciation of words. Then in the 1960s educators dropped such traditional exercises from the curriculum, because they were too rigid, boring, and "not relevant." But the loss of these drills has been costly; they may have been the only opportunity that many students had to systematically exercise the brain function that gives us fluency and grace with symbols, For the rest of us, their disappearance may have contributed to the general decline of eloquence, which requires memory and a level of auditory brainpower unfamiliar to us now. In the Lincoln-Douglas debates of 1858 the debaters would comfortably speak for an hour or more without notes, in extended memorized paragraphs; today many of the most learned among us, raised in our most elite schools since the 1960s, prefer the omnipresent PowerPoint presentation — the ultimate compensation for a weak premotor cortex. Barbara Arrowsmith Young's work compels us to imagine how much good might be accomplished if every child had a brain-based assessment and, if problems were found, a tailor-made program created to strengthen essential areas in the early years, when neuroplasticity is greatest. It is far better to nip brain problems in the bud than to allow the child to wire into his brain the idea that he is "stupid," begin to hate school and learning, and stop work in the weakened area, losing whatever strength he may have. Younger children often progress more quickly through brain exercises than do adolescents, perhaps because in an immature brain the number of connections among neurons, or synapses, is 50 percent greater than in the adult brain. When we reach adolescence, a massive "pruning back" operation begins in the brain, and synaptic connections and neurons that have not been used extensively suddenly die off — a classic case of "use it or lose it." It is probably best to strengthen weakened areas while all this extra cortical real estate is available. Still, brain-based assessments can be helpful all through school and even in college and university, when many students who did well in high school fail because their weak brain functions are overloaded by the increased demand. Even apart from these crises, every adult could benefit from a brain-based cognitive assessment, a cognitive fitness test, to help them better understand their own brain. It's been years since Mark Rosenzweig first did the rat experiments that inspired Barbara and showed her that enriched environments and stimulation lead the brain to grow. Over the years his labs and others have shown that stimulating the brain makes it grow in almost every conceivable way. Animals raised in enriched environments — surrounded by other animals, objects to explore, toys to roll, ladders to climb, and running wheels — learn better than genetically identical animals that have been reared in impoverished environments. Acetylcholine, a brain chemical essential for learning, is higher in rats trained on difficult spatial problems than in rats trained on simpler problems. Mental training or life in enriched environments increases brain weight by 5 percent in the cerebral cortex of animals and up to 9 percent in areas that the training directly stimulates. Trained or stimulated neurons develop 25 percent more branches and increase their size, the number of connections per neuron, and their blood supply. These changes can occur late in life, though they do not develop as rapidly in older animals as in younger ones. Similar effects of training and enrichment on brain anatomy have been seen in all types of animals tested to date. For people, postmortem examinations have shown that education increases the number of branches among neurons. An increased number of branches drives the neurons farther apart, leading to an increase in the volume and thickness of the brain. The idea that the brain is like a muscle that grows with exercise is not just a metaphor. Some things can never be put together again. Lyova Zazetsky's diaries remained mostly a series of fragmented thoughts till the end. Aleksandr Luria, who figured out the meaning of those fragments, could not really help him. But Zazetsky's life story made it possible for Barbara Arrowsmith Young to heal herself and now others. Today Barbara Arrowsmith Young is sharp and funny, with no noticeable bottlenecks in her mental processes. She flows from one activity to the next, from one child to the next, a master of many skills. She has shown that children with learning disabilities can often go beyond compensations and correct their underlying problem. Like all brain exercise programs, hers work best and most quickly for people with only a few areas of difficulty, But because she has developed exercises for so many brain dysfunctions, she is often able to help children with multiple learning disabilities — children like herself, before she built herself a better brain. Chapter 3 Redesigning the Brain A Scientist Changes Brains to Sharpen Perception and Memory, Increase Speed of Thought, and Heal Learning Problems Michael Merzenich is a driving force behind scores of neuroplastic innovations and practical inventions, and I am on the road to Santa Rosa, California, to find him. His is the name most frequently praised by other neuroplasticians, and he's by far the hardest to track down. Only when I found out that he would be at a conference in Texas, went there, and sat myself down beside him, was I finally able to set up a meeting in San Francisco. "Use this e-mail address," he says. "And if you don't respond again?" "Be persistent."At the last minute, he switches our meeting to his villa in Santa Rosa. Merzenich is worth the search. The Irish neuroscientist Ian Robertson has described him as "the world's leading researcher on brain plasticity." Merzenich's specialty is improving people's ability to think and perceive by redesigning the brain by training specific processing areas, called brain maps, so that they do more mental work. He has also, perhaps more than any other scientist, shown in rich scientific detail how our brain- processing areas change. This villa in the Santa Rosa hills is where Merzenich slows down and regenerates himself. This air, these trees, these vineyards, seem like a piece of Tuscany transplanted into North America. I spend the night here with him and his family, and then in the morning we are off to his lab in San Francisco. Those who work with him call him "Merz," to rhyme with "whirs" and "stirs." As he drives his small convertible to meetings — he's been double-booked much of the afternoon — his gray hair flies in the wind, and he tells me that many of his most vivid memories, in this, the second half of his life — he's sixty-one — are of conversations about scientific ideas. I hear him pour them into his cell phone, in his crackling voice. As we pass over one of San Francisco's glorious bridges, he pays a toll he doesn't have to because he's so involved with the concepts we are discussing. He has dozens of collaborations and experiments all going on at once and has started several companies. He describes himself as "just this side of crazy." He is not, but he is an interesting mix of intensity and informality. He was born in Lebanon, Oregon, of German stock, and though his name is Teutonic and his work ethic unrelenting, his speech is West Coast, easygoing, down-to-earth. Of neuroplasticians with solid hard-science credentials, it is Merzenich who has made the most ambitious claims for the field: that brain exercises may be as useful as drugs to treat diseases as severe as schizophrenia; that plasticity exists from the cradle to the grave; and that radical improvements in cognitive functioning — how we learn, think, perceive, and remember — are possible even in the elderly. His latest patents are for techniques that show promise in allowing adults to learn language skills, without effortful memorization. Merzenich argues that practicing a new skill, under the right conditions, can change hundreds of millions and possibly billions of the connections between the nerve cells in our brain maps. If you are skeptical of such spectacular claims, keep in mind that they come from a man who has already helped cure some disorders that were once thought intractable. Early in his career Merzenich developed, along with his group, the most commonly used design for the cochlear implant, which allows congenitally deaf children to hear. His current plasticity work helps learning-disabled students improve their cognition and perception. These techniques — his series of plasticity-based computer programs, Fast ForWord — have already helped hundreds of thousands. Fast ForWord is disguised as a children's game. What is amazing about it is how quickly the change occurs. In some cases people who have had a lifetime of cognitive difficulties get better after only thirty to sixty hours of treatment. Unexpectedly, the program has also helped a number of autistic children. Merzenich claims that when learning occurs in a way consistent with the laws that govern brain plasticity, the mental "machinery" of the brain can be improved so that we learn and perceive with greater precision, speed, and retention. Clearly when we learn, we increase what we know. But Merzenich's claim is that we can also change the very structure of the brain itself and increase its capacity to learn.