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

“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.”

Enlightenment ideals, which portrayed the brain as a machine bound to limitations, are largely responsible for scientists’ bias against neuroplasticity. However, this quote reminds readers that Western thought did not always portray the brain as unchanging: The bias is a product of specific circumstances that shaped the late-17th through 18th centuries in Europe.

“We all have some weak brain functions, and such neuroplasticity-based techniques have great potential to help almost everyone.”

Here, Norman Doidge points out every brain is different, each with its own strengths and weaknesses. In an ideal world, everyone would have the opportunity to find their weaknesses and overcome them with neuroplasticity-based exercises. This point is expanded in later chapters, where Doidge discusses how even the elderly can train their brains to remain more alert.

“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.”

Doidge critiques the contemporary elementary school curriculum for its disregard of motor and repetition-based learning exercises, such as tracing the alphabet or practicing enunciation. He argues that while these exercises can be “boring,” they should not be assumed wasteful: Some students rely on these practices to help their plastic brains develop.

“‘The cerebral cortex,’ he says of the thin outer layer of the brain, ‘is actually selectively refining its processing capacities to fit each task at hand.’ It doesn’t simply learn; it is always ‘learning how to learn.’”

At the core of neuroplasticity is the idea that the brain can change itself by constantly refining its processes: It learns how to learn with more efficiency. Although Doidge does not directly address the question of why the brain evolved to be plastic, this quote hints that a changing brain is better able to adapt to changes in the body and outside environment, making the brain fitter for survival.

“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.”

Doidge believes the brain has a limited amount of neurons and capacity, which means every signal demanding to be processed is vying for attention. If a brain area stops receiving signals from the body, the area will become idle—and neighboring areas will soon covet the space. For example, if someone loses their vision, their other senses will become enhanced by processing sound and touch.

“But when we learn a bad habit, it takes over a brain map, and each time we repeat it, it claims more control of that map and prevents the use of that space for ‘good’ habits. That is why ‘unlearning’ is often a lot harder than learning.”

This quote explains the plastic paradox. Since the brain is constantly learning how to learn, it will be able to process repetitive tasks in a more efficient manner over time. If this repetitive task is a bad habit, it will become ingrained in the brain map, and attempting to change it will disturb the established routine. Learning a new habit tends to be inefficient at first, so the brain will resist the change—which is why neuroplasticity can, ironically, lead to rigidity.

“Instincts generally resist change and are thought to have a clear, non-negotiable, hardwired purpose, such as survival. Yet the human sexual ‘instinct’ seems to have broken free of its core purpose, reproduction, and varies to a bewildering extent, as it does not in other animals, in which the sexual instinct seems to behave itself and act like an instinct.”

This quote summarizes human sexual plasticity. It points out that while other animals engage in sexual activity mainly for reproduction, humans have learned sexual tastes and fetishes that have nothing to do with survival.

“The brain structure that regulates instinctive behaviors, including sex, called the hypothalamus, is plastic, as is the amygdala, the structure that processes emotion and anxiety.”

This quote emphasizes all brain tissue is plastic, including noncortical areas that have less neurons and connections to be made. While they may demonstrate less plasticity than areas with more neurons, they must be capable of adaptation in order to match changes in the brain.

“But the main point is that in our critical periods we can acquire sexual and romantic tastes and inclinations that get wired into our brains and can have a powerful impact for the rest of our lives.”

This quote reiterates that the brain is more plastic during critical periods even in matters of romance and sex. Any pathways created during the critical stage can potentially affect a person’s tastes in the future.

“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.”

Edward Taub’s rehabilitation program has seen success in helping patients recover from paralysis, including some who have not moved their limbs in decades. Although much of this is a result of the plastic brain, Doidge highlights how well-designed training can further the process.

“Not only could the brain respond to damage by having single neurons grow new branches within their own small sectors, but, the experiment showed, reorganization could occur across very large sectors.”

This quote highlights the extent of plasticity. Although brain mapping is useful for understanding why certain tasks are more often processed in certain areas of the brain, personal circumstances can lead to brain maps looking vastly different from one another—to the point where reorganization can happen across sectors.

“We now know, from brain scans, that three parts of the brain are involved in obsessions.”

The three parts of the brain that contribute to obsessive-compulsive behavior are the orbital frontal cortex, cingulate gyrus, and caudate nucleus. When all three functions are wired to function in tandem, they amplify anxieties and prevent thoughts from moving on from triggers.

“Schwartz set out to develop a treatment that would change the OCD circuit by unlocking the link between the orbital cortex and the cingulate and normalizing the functioning of the caudate.”

This quote expands on Important Quote #13. Because the brain is plastic, people with OCD can learn to rewire their brains so their orbital frontal cortex, cingulate gyrus, and caudate nucleus desync. People can do so by taking drugs, which can chemically weaken links; they can also do mental exercises designed to help forge new neuronal connections.

“When we wish to perfect our senses, neuroplasticity is a blessing; when it works in the service of pain, plasticity can be a curse.”

Neuroplasticity can occasionally be detrimental to one’s health, due to the brain’s instinct to respond to signals—imagined or otherwise. This is the case for phantom pain. Doidge later describes how neuroscientists used therapies based on neuroplasticity to address this problem.

“This how remarkable this is—for a most excruciating, chronic pain, a whole new treatment that uses imagination and illusion to restructure brain maps plastically without medication, needles, or electricity.”

This quote expands on Important Quote #15. Since some pains are imagined or the result of “crossed wires” in the brain, the logical cure is to use imagination to repair faulty neuronal connections.

“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.”

This metaphor underlines the importance of sustained practice for acquiring a skill. According to Alvaro Pascual-Leone’s study, there are different plastic mechanisms, one of which acts fast and strengthens existing connections—while the other is slower but helps build new structures. But no matter how fast someone picks up a skill, repetition is often required to maintain change.

“One reason we can change our brains simply by imagining is that, from a neuroscientific point of view, imagining an act and doing it are not as different as they sound.”

This quote underlines the extent to which thoughts can change brains and bodies. Later, Doidge refers to a study which proved imagining moving a finger can help it gain muscle mass without having to move it. This is because many neuronal connections can be made and reinforced through concentration and visualization.

“‘The system is plastic, not elastic,’ Pascual-Leone says in a booming voice. An elastic band can be stretched. But it always reverts to its former shape, and the molecules are not rearranged in the process. The plastic brain is perpetually altered by every encounter, every interaction.”

This quote highlights the difference between elasticity and plasticity. While elastics can be stretched, once they are released, they return to their original shape. Plasticity, on the other hand, is the quality of being constantly refashioned, and once changed, it will never regain its exact shape. This is why the plastic brain is described as an organ constantly “learning to learn.”

“Kandel’s work shows that when we learn our minds also affect which genesin our neurons are transcribed. Thus we can shape our genes, which in turn shape our brain’s microscopic anatomy.”

Thoughts and experiences reshape the brain, and the modified brain reshapes DNA. Doidge argues neuroplasticity is not simply about forging new neuronal connections, but genes, which can be passed on. This expands the extent to which neuroplasticity can affect human nature itself.

“The newest brain scans show that when we dream, that part of the brain that processes emotion, and our sexual, survival, and aggressive instincts, is quite active. At the same time the prefrontal cortex system, which is responsible for inhibiting our emotions and instincts, shows lower activity. With instincts turned up and inhibitions turned down, the dreaming brain can reveal impulses that are normally blocked from awareness.”

This quote defends psychoanalysis as an effective gateway into the psyche, an effective tool for treating trauma and the like. Psychoanalysis proposes certain memories, such as childhood trauma, might not be consciously remembered as trauma, even if they are the cause of depression or anxiety. The quote suggests brain scans and other tools in neuroscience generally support this hypothesis.

“We now know that exercise and mental activity in animals generate and sustain more brain cells, and we have many studies confirming that humans who lead mentally active lives have better brain function.”

This quote encourages readers to consider the advantages of neuroplasticity. It argues everyone is equipped with the ability to improve their mental abilities, as long as they exercise their bodies and minds properly. Later, Doidge argues this is true even for the elderly, who, despite their age, can nevertheless train their malleable brains to remain alert.

“Vaillant concluded that old age is not simply a process of decline and decay, as many younger people think. Older people often develop new skills and are often wiser and more socially adept than they were as younger adults.”

Reiterating Important Quote #22, Doidge is convinced the brain remains trainable until the end of one’s life. This quote is meant to encourage readers, especially older readers, to make the best of neuroplasticity, so they can lead more active, enriched lives for longer.

“When we read, the meaning of a word is stored or ‘mapped’ in one sector of the brain; the visual appearance of the letters is stored in another, and its sound in yet another. Each sector is bound together in a network, so that when we encounter the word, we can see it, hear it, and understand it.”

This quote discusses how several sectors of the brain must work together to accomplish complex tasks, such as literacy. In order for several senses to function at once, the neurons that govern them must be activated at once. Because the task is complex, words that are used more often will be easier to retrieve.