For centuries, science regarded the human brain as a machine, with every component in its place, every task assigned. If a part was broken or worn out, that was that.
It couldn’t be replaced: its function was permanently lost.
It was a bleak supposition, but one borne out by untold numbers of stroke victims who never fully recovered, mentally limited youngsters who never progressed.
It was also wrong.
“There are certain mistakes that only people with high IQs can make,” says Toronto research psychiatrist Dr. Norman Doidge. “The best and the brightest believed that everything had only one function and one location.”
Which meant that people with damaged brains were, if not written off, certainly viewed as damaged for life.
“In the last century,” says Doidge, “rehabilitative medicine was the most gloomy, pessimistic area for a doctor to work in because so many people couldn’t get better.”
In recent years, however, neuroscientists have come to the revolutionary realization that the brain’s anatomy is not, in fact, fixed. It is flexible or, in their terminology, “plastic.”
Injured or dysfunctional cells and circuits can indeed be regenerated and rewired; the location of a given function can, astonishingly, move from one place to another.
The discovery of neuroplasticity – that the brain can be transformed through mental exercise therapy – so intrigued Doidge that it led him on a four-year investigation of the cutting-edge research, scientists and patients behind it.
The Brain That Changes Itself, a panoramic examination of the profound implications, is the newly published result.
Doidge presents extraordinary case histories of learning disorders being reversed, IQs rising, elderly brains replenishing themselves, blind people learning how to see, autistic children starting to relate to the world, and individuals with crippling depression and anxiety moving off the life-ruining treadmill.
Undoubtedly the best illustration of neuro-flexibility he came across is Michelle, a woman who was born 29 years ago with only half a brain – the left hemisphere was, literally, missing.
“You would think that today she’d be on a respirator in a chronic-care hospital, but she’s not,” he says. “Michelle works, loves her family, loves jokes, and votes in elections.”
How? “Because the existing half of her brain totally reorganized itself, probably in the womb and early childhood. It took over the missing left side’s functions” – language, reading, the ability to do math.
Plasticity exists in all areas of the brain: in sensory, motor, and cognitive processing, in the part that regulates instincts (hunger, thirst, sex) and in the part dealing with emotion and anxiety. It even exists in the spinal cord. Through relentless exercise, actor Christopher Reeve was able to retrieve some feeling and mobility after he was paralyzed.
“Neuroplastic therapy can open and redirect pathways to reorganize the brain so that people recover more fully after trauma,” Doidge writes.
University of Wisconsin neuroscientist Paul Bach-y-Rita, whose ground-breaking work is saluted in the book, discovered that if one of our six senses – sight, hearing, taste, touch, smell, balance – is damaged, another can take over for it, a process he called “sensory substitution.”
“We see with our brains, not our eyes,” he told Doidge. “Our eyes only sense changes in light energy.”
Bach-y-Rita – whose death last fall was “a great loss, he put plasticity on the map” – did the groundwork for retinal implants that are giving the blind the chance to see again.
Another profiled pioneer is Michael Merzenich, a neuroscientist at the University of California, San Francisco. He’s developed mental-exercise strategies for autistic and learning-disabled youngsters still in the critical childhood period of intense plasticity, with astounding results. But he’s equally committed to rejuvenating the more rigid-seeming brains of the elderly.
The body’s lifespan may not have to outpace its mental lifespan, as is so often the case today. In his innovative flexibility therapy, Merzenich has found that “everything that you can see happen in a young brain can happen in an older brain.” Deterioration can be reversed by 20 to 30 years.
Indeed, Doidge writes about a 90-year-old doctor he met who had become bothered by momentary lapses in memory, a drop in alertness, weakened handwriting, and a tendency to be less communicative – all classic signs of age-related decline. But within eight weeks of Merzenich’s daily, intensive auditory exercises, he had reclaimed the mental flexibility of a man decades younger.
“The exercises rebuilt the auditory cortex of his brain from the ground up,” Doidge explains.
Better hearing leads to better concentration, which leads to better memory formation. The brain, he stresses, is a use-it-or-lose-it organ.