THIS BOOK IS about the discovery that the human brain has its own unique way of healing, and that when it is understood, many brain problems thought to be incurable or irreversible can be improved, often radically, and in a number of cases, as we shall see, cured. I will show how this process of healing grows out of the highly specialized attributes of the brain—attributes once thought to be so sophisticated that they came at a cost: that the brain, unlike other organs, could not repair itself or restore lost functions. This book will show that the reverse is true: the brain’s sophistication provides a way for it to repair itself and to improve its functioning generally.
This book begins where my first book, The Brain That Changes Itself, ended. That book described the most important breakthrough in under- standing the brain and its relationship to the mind since the beginning of modern science: the discovery that the brain is neuroplastic. Neuro- plasticity is the property of the brain that enables it to change its own structure and functioning in response to activity and mental experience. That book also described many of the first scientists, doctors, and patients to make use of this discovery to bring about astonishing transformations in the brain. Until then, these transformations had been almost inconceivable, because for four hundred years, the mainstream view of the brain was that it could not change; scientists thought the brain was like a glorious machine, with parts, each of which performed a single mental function, in a single location in the brain. If a location was damaged—by a stroke or an injury or a disease—it could not be fixed because machines cannot repair themselves or grow new parts. Scientists also believed the circuits of the brain were unchangeable or “hardwired,” meaning that people born with mental limitations or learning disorders were in all cases des- tined to remain so. As the machine metaphor evolved, scientists took to describing the brain as a computer and its structure as “hardware” and believed the only change that aging hardware undergoes is that it de- generates with use. A machine wears out: use it, and lose it. Thus, at- tempts by older people to preserve their brains from decline by using mental activity and exercise were seen as a waste of time.
The neuroplasticians, as I called the scientists who demonstrated that the brain is plastic, refuted the doctrine of the unchanging brain. equipped, for the first time, with the tools to observe the living brain’s microscopic activities, they showed that it changes as it works. In 2000 the Nobel Prize in Physiology or Medicine was awarded for demonstrating that as learning occurs, the connections among nerve cells increase. The scientist behind that discovery, Eric Kandel, also showed that learning can “switch on” genes that change neural structure. Hundreds of studies went on to demonstrate that mental activity is not only the product of the brain but also a shaper of it. Neuroplasticity restored the mind to its rightful place in modern medicine and human life.
THE INTELLECTUAL REVOLUTION DESCRIBED IN The Brain That Changes Itself was the beginning. Now, in this book, I tell of the astounding advances of a second generation of neuroplasticians who, be- cause they did not have the burden of proving the existence of plasticity, have been liberated to devote themselves to understanding and using plasticity’s extraordinary power. I have traveled to five continents to meet with them—the scientists, clinicians, and their patients—in order to learn their stories. Some of these scientists work in the cutting-edge neuroscience labs of the Western world; others are clinicians who have applied that science; and still others are clinicians and patients who together stumbled upon neuroplasticity and perfected effective treatment techniques, even before plasticity had been demonstrated in the lab.
One patient after another in this book had been told they would never get better. For decades, the term healing was seldom used in connection with the brain, as it was with other organ systems, such as the skin or the bones or the digestive tract. While organs such as the skin, liver, and blood could repair themselves by replenishing their lost cells using stem cells to function as “replacement parts,” no such cells were found in the brain, despite decades of searching. Once neurons were lost, no evidence could be found that they were ever replaced. Scientists tried to find ways to explain this in evolutionary terms: in the course of evolving into an organ with millions of highly specialized circuits, the brain simply lost the ability to supply those circuits with replacement parts. even if neuronal stem cells—baby neurons—were to be found, how, it was wondered, would they be of any help? How would they ever integrate into the sophisticated but dizzyingly complex circuits of the brain? Because it wasn’t thought possible to heal the brain, most treatments used medication to “prop up the failing system” and decrease symptoms by temporarily changing the chemical balance in the brain. But stop the medication, and the symptoms would return.