Today's post is more about brain plasticity, which can work two ways. The brain can increase one's ability to do something of value but it can also work to eliminate a valuable ability if the ability is not used. This quote is from chapter three of "The Brain's Way of Healing" by Norman Doidge, MD.
The Pervasiveness of Learned Nonuse
Since I wrote "The Brain That Changes Itself", three things have become apparent to me. The first is that learned nonuse applies not only to stroke. As discussed in the previous chapter, people who have had a stroke go through a crisis— diaschisis —in which the brain, immediately after the injury, goes into shock for about six weeks and functions poorly. Edward Taub showed that when a stroke patient tries repeatedly, during this period, to move the paralyzed arm, and cannot, he "learns" it doesn't work and so starts using only his nonaffected limb. In the use -it-or-lose-it brain, the already-damaged circuitry for the paralyzed arm withers further . Taub proved that if the good arm was put in a cast or sling, so that it couldn't be used, then extremely intensive , incremental training of the paralyzed arm could often restore function, even decades later.
By 2007 Taub had shown that brain injuries caused by radiation treatments also lead to learned nonuse. He has since found that it can occur in a partial spinal cord injury, cerebral palsy, aphasia (loss of speech from a stroke), multiple sclerosis, traumatic brain injuries, and people who have had brain surgery for epilepsy, and that these conditions can respond to his therapy. * I began to see that learned nonuse could occur in other brain problems, such as Parkinson's, and even, at times, it seemed, in some psychiatric problems. Indeed, in any situation where brain function is lost or on the wane, a person may be understandably tempted to find ways to work around the deficit— and thereby unintentionally exacerbate the loss of this circuitry. The widespread if not universal existence of learned nonuse means that often we cannot judge the level of a person's deficit, or potential to recover, until we first try to train the individual vigorously.
Doidge, Norman (2015-01-27). The Brain's Way of Healing: Remarkable Discoveries and Recoveries from the Frontiers of Neuroplasticity (Kindle Locations 1844-1857). Penguin Group US. Kindle Edition.
Another book on the same subject is "Soft-Wired: How the New Science of Brain Plasticity Can Change Your Life" by a prominent researcher in the field, Dr. Michael Merzenich. Merzenich explains how brain change works:
1. Change is mostly limited to those situations in which the brain is in the mood for it. If I am alert, on the ball, engaged, motivated, ready for action —the brain releases those chemical modulatory neurotransmitters that enable brain change. Again, it's helpful to think of them as on/ off switches. When I'm in a learning mode— alert, concentrated, and focused— the brain's plasticity switches are turned "on" and ready to facilitate change. If I'm disengaged, inattentive, distracted, sleeping, twiddling my thumbs, doing something without thinking about it, or performing an action that requires no real effort to succeed on my part, my switches are mostly turned "off."
He also writes:
7. The brain is changed by internal mental rehearsal in the same ways, and involving precisely the same processes, that control changes achieved through interactions with the external world. You don't have to move an inch to drive positive plastic change in your brain. Your internal representations of things recalled from memory work just fine for progressive brain plasticity-based learning!
10. Brain plasticity is a two-way street; it is just as easy to generate negative changes as it is to produce positive ones. There are winners and losers in the game of brain plasticity. It is almost as easy to drive changes that can impair one's memory or slow down one's mental or physical control as it is to improve one's memory, or speed up the brain's actions. As I'll discuss in detail later, many older individuals are absolute masters at driving their brain plasticity in the wrong direction!
Merzenich, Michael (2013-08-02). Soft-Wired: How the New Science of Brain Plasticity Can Change your Life (p. 46-50). Parnassus Publishing. Kindle Edition.
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Bill
Main blog: Fear, Fun and Filoz
Main web site: Kirbyvariety
