The evolution of the theory of brain plasticity traverses from the 1800s' view of the “hardwired brain” to today's view of a malleable brain.
In The Brain that Changes Itself, Norman Doidge, MD, takes us on this journey through time, unraveling one of the most revolutionary breakthroughs in neuroscience — the discovery of neuroplasticity. He shares the discoveries that have overthrown the centuries-old notion that the adult brain is fixed and unchanging.
Through case histories, we learn of the brain's remarkable ability to adapt and modify its structure and the astonishing progress of people whose conditions were initially dismissed as hopeless — a woman labeled as retarded who cured her deficits with brain exercises, for example, and a woman born without a left hemisphere who through massive brain re-organization is able to work part-time and function with only her right hemisphere.
We meet a woman with a severely damaged vestibular system who today functions normally after training with artificial sensors on her tongue that were designed by brain-plasticity pioneer Paul Bach-y-Rita. We learn about another woman who, despite being wheelchair-bound after an anoxic brain injury, remembers day-to-day events and works part-time, the result of intensive training integrating Jordan Grafman's memory research. We share the triumph of an autistic child and his parents, as he speaks more and uses complete sentences after attending a program based on years of Michael Merzenich's neuroplasticity research.
THE SEARCH FOR ANSWERS
As a psychiatrist and psychoanalyst, Dr. Doidge became interested in the idea of a changing brain when his patients did not progress psychologically as he had hoped. Dissatisfied with the conventional wisdom that the human brain was “hardwired” and unchangeable, Dr. Doidge embarked on a journey to investigate the evidence for brain plasticity. This book is the result of his interviews with scientists, doctors, and patients from across the US who personally experienced the remarkable changes in brain structure and function that can happen given the proper input.
These scientists and clinicians provide evidence that activity or mental exercise can alter brain structure, even in the latest stages of life. Dr. Doidge names these pioneers the “neuroplasticians,” who persevered despite criticism and rejection, to uncover the power and adaptability of the brain.
BRAIN PLASTICITY UNRAVELED
In 1968, brain plasticity pioneer Michael Merzenich reported that the brain could normalize its structure in response to abnormal input, and hence the brain had to be plastic. He had cut the peripheral nerve in the hand of a monkey and sewed the two severed ends close together but not touching and proposed that the nerves for the thumb and index finger would cross as the peripheral nerve regenerated itself. Seven months later, to Merzenich's surprise, the brain map — the topographical areas of the brain responsible for specific neurologic processes identified with imaging or other diagnostic techniques — was topographically arranged as though the brain had unshuffled the signals from the crossed nerves.
Merzenich's post-doctoral mentor, however, told him that his conclusions were too conjectural. It was not until the late 1980s that Merzenich persuaded skeptics in the scientific community that the adult brain is indeed plastic. Today, his companies Posit Science and Scientific Learning are dedicated to helping the aged and learning-impaired alter and preserve brain plasticity. Posit Science's Brain Fitness Program, for example, uses a series of computer-based exercises to improve memory and processing speed in adults.
Dr. Doidge describes compelling evidence that both mental rehearsal and physical practice produce similar physical changes in the brain motor system; that muscles are strengthened by imagined training; and that the brain maps associated with fingers involved in reading Braille are larger than the brain maps of adjacent fingers. He also describes how brain scans following treatment for obsessive compulsive disorder provide evidence that the three parts of the brain (frontal cortex, cingulate gyrus, caudate) that had been firing together in a hyperactive way begin to fire separately in a normal way, easing anxiety and compulsive behavior.
We also learn that new neurons can form in the brain at the latest stages of life and that memories can improve substantially by engaging in exercises that enhance the speed of processing information: A 2006 Proceedings of the National Academy of Sciences study provided evidence that people 60 years or older can improve their memory by 10 years or more by using Merzenich's Brain Fitness Program.
A STORY WELL TOLD
Dr. Doidge has provided us with a comprehensive view of the profound changes in scientific thought that have evolved over the past three centuries. He describes how the neuroplastic revolution is teaching us the influence of relationships, learning, addiction, culture, technology, and psychotherapies on brain function.
The layperson learns that the brain's capacity for change is limitless; the clinician is inspired to provide hope to patients; and the scientist is challenged to continue to unravel the many mysteries of our brains. Reading this book is time well spent, and will alter your view of the astonishing capabilities of the brain. •