The notion that the human brain is "hard-wired" was a favorite theme even up to recently, because it helped explain how certain behaviors were determined by genes. We were told that depression, addiction, even obesity were not the result of choice or environment. Rather, these and a host of other behaviors were rooted in the brain and ultimately in a person's DNA. Poplar articles continue to appear on how women's brains are wired differently from men's, or the teenage brain from either children's or adult's. This theory was always a half-truth, and now evidence is arising to show that the brain may be much more flexible than was supposed, which is good news for anyone who believes in freedom of choice as well as consciousness itself. One need only turn to the work of the late Dr. Paul Bach-y-Rita from Mexico, who attracted general scorn thirty years ago when he suggested that the brain was capable of "sensory substitution." That is, a blind person could learn to "see," for example, by substituting the sense of touch for the sense of sight. Braille already gave a clue that something akin to this audacious idea was possible, but Dr. Bach-y-Rita went much further. By the time of his death at 72 last year, he had developed a mechanism known as a "Brain Port," a small paddle that fits on the tongue. Using a grid of 600 electrical points attached to a camera, the Brain Port can deliver a picture to the tongue of whatever the camera sees. This picture consists of electrical impulses that activate touch, yet after some practice, the blind person's brain actually sees the image. As proof, MRIs have shown that the visual cortex of the blind person is lighting up when signals are sent to the tongue. In a recent PBS spot, the viewer could watch blind patients throwing a tennis ball into a trash can from 20 feet and walking a curving path without going out of bounds. But sensory substitution goes farther. A woman who had lost her sense of balance thanks to the side effect of an antibiotic could not be helped by drugs or surgery because the entire vestibular labyrinth in the inner ear had been rendered completely useless. Yet by training with the Brain Port, which told her tongue when she was upright and when she wasn't, she regained her balance. And here comes the most remarkable part. Over time, her brain had learned to rebalance so well without using the inner ear that the woman could walk and ride a bike without wearing the Brain Port device at all. The complexity of the vestibular system that controls equilibrium is extreme, and yet much or all of it found a substitute. Not only has Dr. Bach-y-Rita proved his point that the brain is much more flexible than supposed, his research suggests that the brain is much more creative as well, and therefore more mysterious. For after all, how does an organ that is mostly water and is governed entirely by electro-chemical impulses know that a person needs a new way of sensing the world, one that so far as we know wasn't necessary to human evolution? (to be cont.)
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