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

Nonfiction | Book | Adult | Published in 2007

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Summary

Background

Chapter Summaries & Analyses

Chapters 1-4

Chapters 5-8

Chapters 9-11

Key Figures

Themes

Index of Terms

Important Quotes

Essay Topics

Tools

Beta

Discussion Questions

Themes

Localizationism and Research on Neuroplasticity

Localizationism is an approach to neuroscience that separates the brain into different areas, each in charge of processing a specific type of information. This theory has a rigid understanding of brain structure and until the 1960s assumed permanent damage to an area meant all its processes were lost. For example, neuroscientists believed damage to the Broca area might prevent speech. The Brain That Changes Itself explains there are three main reasons for the scientific community’s initial skepticism of neuroplasticity. The first reason is that early on, people who suffered brain damage rarely recovered their full faculties; instances of recovery were dismissed as outliers. The second reason is the lack of tools to measure the living brain, which rendered the organ mysterious. The third reason is the preeminence of certain schools of thought, which encouraged the belief of the body as either a hardwired machine or a passive vessel responding to outside stimuli—both of which tend to dismiss plasticity. As per philosopher René Descartes, Cartesianism separates the body (including the brain, framed as unchanging) from the soul (the true self, capable of change). Meanwhile, behaviorism depicts human and animal biology as largely passive; related research focuses on learning how the body responds to stimuli, and tends to portray this response as reflexive, rather than the product of learning.

It took years for the medical field to legitimize the idea that the brain could change. Norman Doidge believes the various discoveries of the 1960s and ’70s, which paved the way for more research on neuroplasticity, could be considered the greatest breakthroughs in medical science in recent times. Neuroplasticity has since influenced the social sciences, physical sciences, and humanities, and altered experts’ approach to disciplines such as philosophy, physiotherapy, and psychoanalysis. This theme is discussed throughout Chapters 1-4, though it recurs in the rest of the book. The purpose of the book is to challenge the very concept of localizationism by demonstrating the brain is plastic.

Neuroplasticity and Rigidity

The brain is continuously learning how to learn, and it is this flexibility that allows neurons to form stronger connections, so practiced tasks become easier to perform over time. However, it is this specialization that paradoxically creates rigidity: Once a task is mastered, it becomes harder to modify it, because any change will disturb the brain’s routine. Even if this “disturbance” is temporary and may ultimately be better, the brain tends to resist change because of its initial energy cost. For example, in Chapter 5, Edward Taub’s research revealed monkeys whose sensory neurons were cut never moved their affected limbs again, even though their motor neurons were not damaged. This is because the sudden removal of sensory neurons sent a shock throughout their bodies, and subsequently, the monkeys found it easier to move their unaffected limbs rather than relearn to move their affected limbs. The monkeys’ brains had to relearn to detect signals from limbs, but it was simply easier to rely on unaffected limbs. It is only when the monkeys’ unaffected limbs were restricted that they were forced to use their affected limbs and rewire their brains to process new signals.

The plastic paradox explains why bad habits, once established, are difficult to unlearn. However, if given the right incentives, the brain can accomplish wonders—such as helping limbs recover from paralysis after decades of not moving. Chapter 5 details Taub’s style of rehabilitation, which helped many patients with brain damage recover motor functions. Likewise, in Chapters 7-9, various neuroscientists proved psychological conditions such as OCD and phantom pain can often be treated with relatively simple devices and deliberate imagination. In other words, the brain can be “tricked” into sending and stopping signals between body parts. The plastic paradox can cause and slow conditions, but also accelerate healing from conditions.

Neuroplasticity and Environmental Influence

The book presents the plastic brain as both an active bringer of change and a vessel shaped by its environment. Neuroplasticity differs from both Cartesianism and behaviorism by neither dismissing the brain’s adaptation nor overstating its passivity. Although environmental influence is thematically similar to the plastic paradox in underlining the brain’s nature, it is treated, especially in Chapters 9-11, as a call to action—encouraging readers to take advantage of the brain’s flexibility to expand their skillset and ultimately lead healthier, longer lives. Doidge explains that, in infancy, neurons in the brain have yet to specialize and brain maps remain malleable. This is because infants are unaware of which skills might become helpful later in life; therefore, their brains absorb all stimuli and gradually learn to sort them according to survival. Because the brain is malleable in infancy, there are critical learning periods that allow for easier language learning with repetition—an advantage which fades once a child specializes in a language. In other words, one’s environment affects the development of their brain structure.

Similarly, children who suffer trauma during critical learning periods often have a greater chance of developing unhealthy conditions later in life. Missing critical periods for emotional growth can impact one’s ability to maintain healthy relationships and put one at a higher risk of depression or anxiety. In Chapter 9, Doidge’s patient Mr. L. lost his mother at the critical age of 26 months, as his right orbitofrontal system finished developing and awaited reinforcement. This area of the brain regulates emotions, but he was never taught to understand his grief. His environment conditioned him to “autoregulate” his emotions by shutting down, later leading to detachment and depression. Although the brain is often shaped by its environment, it is not simply a passive subject of circumstances. Mr. L. worked through his childhood trauma by actively rewiring his brain map, so past triggers were retranscribed with new understanding. Similarly, in Chapter 11, Michelle, who was born without the left hemisphere of her brain, developed her right one so it could work in the left’s stead. This reconstruction of the brain is a testament to its ability to transcend the constraints of various environments.