HOW THE BRAIN REWIRES ITSELF
by Sharon Begley in Time Magazine, January 29, 2007
    There are "uncharted worlds" inside your head, but science is drawing a "map." A TIME Magazine special section reports what's new.
TIME Magazine's Mind & Body Special Issue (p55-120)

    PART 3 --- HOW THE BRAIN REWIRES ITSELF (p72-79)

    Not only can the brain learn new tricks, but it can also change its structure and function --- even in old age!

      [1] Introduction (p72-74)

        Volunteer subjects played a simple piano piece as fluently as possible every day for five days after practicing for two hours. Then they took a "TMS test" (transcranial-magnetic-stimulation), sitting beneath a coil of wire that sent a brief magnetic pulse into the "motor cortex" of their brains. "The test allowed brain scientists to infer the function of neurons just beneath the coil:"

        "In the piano players, the TMS mapped how much of the motor cortex controlled the finger movements needed for the piano exercise. What the scientists found was that after a week of practice, the stretch of motor cortex devoted to these finger movements [spread over] surrounding areas."

        "The finding was in line with a growing number of discoveries at the time showing that greater use of a particular muscle causes the brain to devote more cortical [area] to it." Thus just imagining something can stimulate brain neuronal networks similarly to actually seeing the same object or doing the same activity. (p72, 74)

        The lead neuroscientist, Alvaro Pascual-Leone, "extended the experiment by having another group of volunteers merely think about practicing the piano exercise. They played the simple piece of music in their head, holding their hands still while imagining how they would move their fingers. Then they too sat beneath the TMS coil."

        [When the scientists compared] the TMS data on the two groups --- those who actually [played] and those who only imagined doing so --- they [got evidence of] a revolutionary idea about the brain; [namely,] the ability of mere thought to alter the physical structure and function of [neuronal networks in human brain tissue]. [The TMS test had revealed the fact that] the region of motor cortex that controls the piano-playing fingers also expanded in the brains of volunteers who [only] imagined playing the music --- just as it had in those who actually played it."

        [The research proved that ] "mental practice resulted in a similar reorganization of the brain. If the results hold for other forms of movement (and there is no reason to think they don't), then mentally practicing a golf swing or a forward pass or a swimming turn could lead to mastery with less physical practice."

        "Even more profound, the discovery showed that mental training had the power to change the physical structure of the [human] brain."

      [2] Overthrowing the dogma (p74)

        "For decades, the prevailing dogma in neuroscience was that the adult human brain is essentially immutable, hardwired, fixed in form and function, so that by the time we reach adulthood we are pretty much stuck with what we have...This view held that if genes and development dictate that one cluster of neurons will process signals from the eye and another cluster will move the fingers of the right hand, then they will do that and nothing else until the day you die."

        "This doctrine of the unchanging human brain had had profound ramifications...It implied that brain-based fixities, such as the happiness set point [that] a person returns to after the deepest tragedy or the greatest joy, are nearly unalterable. But research in the past few years has overthrown that dogma. In its place has come the realization that the adult brain retains impressive powers of "neuroplasticity," [which is] the ability [of the brain] to change its structure and function in response to experience."

        "These are not minor tweeks either...Even when the brain suffers a trauma late in life, [such as a stroke], a new technique called constraint-induced movement therapy can coax next-door regions [of the brain] to take over the function of the damaged area. [Your] brain can be rewired!"

        "When signals from the skin or muscles bombard the motor cortex or the somatosensory cortex that processes touch, [for example,] the brain expands the area that is wired to move, [such as] the fingers. In this [profound] sense, the very structure of our brain --- the relative size of different regions, the strength of connections between them, even their functions --- reflects the lives we have led."

        "[Your] brain bears the [impact] of the decisions that you have made, the skills you have learned, and the actions you have taken."

      [3] Scratching a phantom limb (p77)

      [4] Thinking about thinking (p77-78)

        [5] Happiness and meditation (p79)

          Meditation can move the "happiness set-point" of monks

      Sharon Begley is the author of the new book, Train Your Brain, Change Your Life Ballantine Books, 2007.

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