The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science

by Norman Doidge

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.

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.

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.

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 Rosenzweig 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.

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 brain-power unfamiliar to us now.

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.

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.

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.

Language development, for instance, has a critical period that begins in infancy and ends between eight years and puberty. After this critical period closes, a person’s ability to learn a second language without an accent is limited. In fact, second languages learned after the critical period are not processed in the same part of the brain as is the native tongue.

The competitive nature of plasticity affects us all. There is an endless war of nerves going on inside each of our brains. If we stop exercising our mental skills, we do not just forget them: the brain map space for those skills is turned over to the skills we practice instead. If you ever ask yourself, “How often must I practice French, or guitar, or math to keep on top of it?” you are asking a question about competitive plasticity. You are asking how frequently you must practice one activity to make sure its brain map space is not lost to another.

task.

When a child learns to play piano scales for the first time, he tends to use his whole upper body—wrist, arm, shoulder—to play each note. Even the facial muscles tighten into a grimace. With practice the budding pianist stops using irrelevant muscles and soon uses only the correct finger to play the note. He develops a “lighter touch,” and if he becomes skillful, he develops “grace” and relaxes when he plays. This is because the child goes from using a massive number of neurons to an appropriate few, well matched to the task. This more efficient use of neurons occurs whenever we become proficient at a skill, and it explains why we don’t quickly run out of map space as we practice or add skills to our repertoire.

That’s why learning a new language in old age is so good for improving and maintaining the memory generally. Because it requires intense focus, studying a new language turns on the control system for plasticity and keeps it in good shape for laying down sharp memories of all kinds. No doubt

Merzenich himself is an advocate of learning a new language in old age. “You will gradually sharpen everything up again, and that will be very highly beneficial to you.

These exercises are now available in thirty independent-living communities and for individuals through the Posit Science Web site.

Currently Taub is studying what length of training is best. He has begun to get reports from clinicians that three hours a day may produce good results and that increasing the number of movements per hour is better than undergoing the exhausting six hours of treatment. What rewires patients’ brains is not mitts and slings, of course. Though they force the patients to practice using their damaged arms, the essence of the cure is the incremental training or shaping, increasing in difficulty over time. “Massed practice”—concentrating an extraordinary amount of exercise in only two weeks—helps rewire their brains by triggering plastic changes.

They do not allow you to say the word ‘can’t,’ which Christine called ‘the four-letter word.

“And,” says Nicole, “they weren’t allowed to use the word ‘

Based on his work with plasticity, Taub has discovered a number of training principles: training is more effective if the skill closely relates to everyday life; training should be done in increments; and work should be concentrated into a short time, a training technique Taub calls “massed practice,” which he has found far more effective than long-term but less frequent training.

Many of these same principles are used in “immersion” learning of a foreign language. How many of us have taken language courses over years and not learned as much as when we went to the country and “immersed” ourselves in the language for a far shorter period? Our time spent with people who don’t speak our native tongue, forcing us to speak theirs, is the “constraint.” Daily immersion allows us to get “massed practice.” Our accent suggests to others that they may have to use simpler language with us; hence we are incrementally challenged, or shaped. Learned nonuse is thwarted, because our survival depends on communication.

He is involved in a cure for tinnitus, or ringing in the ears, that can be caused by plastic changes in the auditory cortex.

With obsessions and compulsions, the more you do it, the more you want to do it; the less you do it, the less you want to do it.

By getting his patients to concentrate on the new behavior intensively, in thirty-minute segments, he is giving them massed practice.

In chapter 3, “Redesigning the Brain,” we learned two key laws of plasticity that also underlie this treatment. The first is that Neurons that fire together wire together. By doing something pleasurable in place of the compulsion, patients form a new circuit that is gradually reinforced instead of the compulsion. The second law is that Neurons that fire apart wire apart. By not acting on their compulsions, patients weaken the link between the compulsion

Emma’s blindness has reorganized her brain and her life. A number of us who were at the dinner are interested in literature, but since she has gone blind, Emma has done more reading than any of us. A computer program from Kurzweil Educational Systems reads books aloud to her in a monotone that pauses for commas, stops for periods, and rises in pitch for questions. This computer voice is so rapid, I cannot make out a single word. But Emma has gradually learned to listen at a faster and faster pace, so she is now reading at about 340 words a minute and is marching through all the great classics. “I get into an author, and I read everything he has ever written, and then I move on to another.” She has read Dostoyevsky (her favorite), Gogol, Tolstoy, Turgenev, Dickens, Chesterton, Balzac, Hugo, Zola, Flaubert, Proust, Stendhal, and many others. Recently she read three Trollope novels in one day. She asked me how it might be possible for her to read so much more quickly than before she went blind. I theorized that her massive visual cortex, no longer processing sight, had been taken over for auditory processing.

Pascual-Leone’s parents, both physicians, sent him to a German school in Spain, where, like many neuroplasticians, he studied the classical Greek and German philosophers before turning to medicine. He took his combined M.D. and Ph.D. in physiology in Freiburg, then went to the United States for further training.

Understanding this tortoise-and-hare effect can help us understand what we must do to truly master new skills. After a brief period of practice, as when we cram for a test, it is relatively easy to improve because we are likely strengthening existing synaptic connections. But we quickly forget what we’ve crammed—because these are easy-come, easy-go neuronal connections and are rapidly reversed. Maintaining improvement and making a skill permanent require the slow steady work that probably forms new connections. If a learner thinks he is making no cumulative progress, or feels his mind is “like a sieve,” he needs to keep at the skill until he gets “the Monday effect,” which in Braille readers took six months. The Friday-Monday difference is probably why some people, the “tortoises,” who seem slow to pick up a skill, may nevertheless learn it better than their “hare” friends—the “quick studies” who won’t necessarily hold on to what they have learned without the sustained practice that solidifies the learning.

He would study the way thoughts change the brain by using TMS to observe changes in the finger maps of people learning to play the piano. One of Pascual-Leone’s heroes, the great Spanish neuro-anatomist and Nobel laureate Santiago Ramón y Cajal, who spent his later life looking in vain for brain plasticity, proposed in 1894 that the “organ of thought is, within certain limits, malleable, and perfectible by well-directed mental exercise.” In 1904 he argued that thoughts, repeated in “mental practice,” must strengthen the existing neuronal connections and create new ones. He also had the intuition that this process would be particularly pronounced in neurons that control the fingers in pianists, who do so much mental practice.

The details of the imagining experiment were simple and picked up Cajal’s idea to use the piano. Pascual-Leone taught two groups of people, who had never studied piano, a sequence of notes, showing them which fingers to move and letting them hear the notes as they were played. Then members of one group, the “mental practice” group, sat in front of an electric piano keyboard, two hours a day, for five days, and imagined both playing the sequence and hearing it played. A second “physical practice” group actually played the music two hours a day for five days. Both groups had their brains mapped before the experiment, each day during it, and afterward. Then both groups were asked to play the sequence, and a computer measured the accuracy of their performances. Pascual-Leone found that both groups learned to play the sequence, and both showed similar brain map changes. Remarkably, mental practice alone produced the same physical changes in the motor system as actually playing the piece. By the end of the fifth day, the changes in motor signals to the muscles were the same in both groups, and the imagining players were as accurate as the actual players were on their third day. The level of improvement at five days in the mental practice group, however substantial, was not as great as in those who did physical practice. But when the mental practice group finished its mental training and was given a single two-hour physical practice session, its overall performance improved to th...

Some athletes and musicians use it to prepare for performances, and toward the end of his career the concert pianist Glenn Gould relied largely on mental practice when preparing himself to record a piece of music.

We know from brain scans of people who use massive amounts of mental practice what was probably happening in Sharansky’s brain while he was in prison. Consider the case of Rüdiger Gamm, a young German man of normal intelligence who turned himself into a mathematical phenomenon, a human calculator. Though Gamm was not born with exceptional mathematical ability, he can now calculate the ninth power or the fifth root of numbers and solve such problems as “What is 68 times 76?” in five seconds. Beginning at age twenty, Gamm, who worked in a bank, began doing four hours of computational practice a day. By the time he was twenty-six, he had become a calculating genius, able to make his living by performing on television. Investigators who examined him with a positron emission tomography (PET) brain scan while he was calculating found he was able to recruit five more brain areas for calculating than “normal” people. The psychologist Anders Ericsson, an expert in the development of expertise, has shown that people like Gamm rely on long-term memory to help them solve mathematical problems when others rely on short-term memory. Experts don’t store the answers, but they do store key facts and strategies that help them get answers, and they have immediate access to them, as though they were in short-term memory. This use of long-term memory for problem solving is typical of experts in most fields, and Ericsson found that becoming an expert in most fields usually takes about a decade ...

What these “imaginary” experiments show is how truly integrated imagination and action are, despite the fact that we tend to think of imagination and action as completely different and subject to different rules. But consider this: in some cases, the faster you can imagine something, the faster you can do it.

The mental “tracks” that get laid down can lead to habits, good or bad. If we develop poor posture, it becomes hard to correct. If we develop good habits, they too become solidified. Is it possible, once “tracks” or neural pathways have been laid down, to get out of those paths and onto different ones? Yes, according to Pascual-Leone, but it is difficult because, once we have created these tracks, they become “really speedy” and very efficient at guiding the sled down the hill. To take a different path becomes increasingly difficult. A roadblock of some kind is necessary to help us change direction.

Everything your “immaterial” mind imagines leaves material traces. Each thought alters the physical state of your brain synapses at a microscopic level. Each time you imagine moving your fingers across the keys to play the piano, you alter the tendrils in your living brain.

Most people assume that our genes shape us—our behavior and our brain anatomy. Kandel’s work shows that when we learn our minds also affect which genes in our neurons are transcribed. Thus we can shape our genes, which in turn shape our brain’s microscopic anatomy.

Kandel argues that when psychotherapy changes people, “it presumably does so through learning, by producing changes in gene expression that alter the strength of synaptic connections, and structural changes that alter the anatomical pattern of interconnections between nerve cells of the brain.” Psychotherapy works by going deep into the brain and its neurons and changing their structure by turning on the right genes. Psychiatrist Dr. Susan Vaughan has argued that the talking cure works by “talking to neurons,” and that an effective psychotherapist or psychoanalyst is a “microsurgeon of the mind” who helps patients make needed alterations in neuronal networks.

Scores of studies show that sleep affects plastic change by allowing us to consolidate learning and memory. When we learn a skill during the day, we will be better at it the next day if we have a good night’s sleep. “Sleeping on a problem” often does make sense.

I talked with him shortly after he completed the series of brain exercises Merzenich’s team developed with Posit Science. Dr. Karansky hadn’t seen cognitive decline, though he adds, “My handwriting was good but not as good as it was before.” He simply hoped to keep his brain fit. He began the auditory memory program in August 2005 by inserting a CD into his computer, and found the exercises “sophisticated and entertaining.” They required him to determine if sounds were sweeping up in frequency or down, to pick the order in which he heard certain syllables, identify similar sounds, and listen to stories and answer questions about them—all in order to sharpen brain maps and stimulate the mechanisms that regulate brain plasticity. He worked on the exercises for an hour and a quarter, three times a week, for three months.

Even though the exercises are for auditory memory, he’s been getting general benefits, as did the children who did Fast ForWord, because he is stimulating not only his auditory memory but also the brain centers that regulate plasticity.

Dr. Karansky describes himself as a lifelong self-educator. He reads serious mathematics and loves games, word puzzles, double acrostics, and Sudoku.

“I like to read about history,” he says. “I tend to get interested in a period, for whatever reason, and I get started, and I mine that period for a while, until I feel I’ve learned enough about it to learn something else.

He is always looking for novel things to do, and once he’s engaged in something, he turns his full attention to it—the necessary condition for plastic change.

His philosophical attitude also protects his brain because he doesn’t get worked up about little things—no small matter, since stress releases glucocorticoids, which can kill cells in the hippocampus.

Thus physical exercise and learning work in complementary ways: the first to make new stem cells, the second to prolong their survival.

The more education we have, the more socially and physically active we are, and the more we participate in mentally stimulating activities, the less likely we are to get Alzheimer’s disease or dementia.

Not all activities are equal in this regard. Those that involve genuine concentration—studying a musical instrument, playing board games, reading, and dancing—are associated with a lower risk for dementia. Dancing, which requires learning new moves, is both physically and mentally challenging and requires much concentration. Less intense activities, such as bowling, babysitting, and golfing, are not associated with a reduced incidence of Alzheimer

Dr. Karansky, it turns out, was doing everything right to fight off age-related memory loss, making him an exemplary model for the common practices we should all be pursuing.

Physical activity is helpful not only because it creates new neurons but because the mind is based in the brain, and the brain needs oxygen. Walking, cycling, or cardiovascular exercise strengthens the heart and the blood vessels that supply the brain and helps people who engage in these activities feel mentally sharper—as pointed out by the Roman philosopher Seneca two thousand years ago. Recent research shows that exercise stimulates the production and release of the neuronal growth factor BDNF, which, as we saw in chapter 3, “Redesigning the Brain,” plays a crucial role in effecting plastic change. In fact, whatever keeps the heart and blood vessels fit invigorates the brain, including a healthy diet.

Tai chi, though it hasn’t been studied, requires intense concentration on motor movements and stimulates the brain’s balance system. It also has a meditative aspect, which has been proven very effective in lowering stress and so is likely to preserve memory and the hippocampal neurons.