Shattered Nerves: How Science Is Solving Modern Medicine's Most Perplexing Problem

12 Pins and Needles in the Brain

∑ 12 Pins and Needles in the Brain The entire field of neural prostheses involves placing manmade objects in the body to interface with the nervous system. And in the order of things, the brain is the crowning confluence of the nervous system. It is where the nervous system begins and ends. The brain originates signals to enable thought and movement, and it receives signals from every sensory organ in the body—eyes, ears, nose, tongue, and skin—and sorts them into some orderly fashion so that we can make sense out of those signals and react to them. When you see a painting, or hear music, or taste a fine meal, or smell a fragrant flower, it is not really the sensory organs that enable you to experience those pleasures. They are merely the messengers that pick up the packets of information and transmit them to your brain, which is where the experience is interpreted. So in the final analysis, when the goal is to provide neural prosthetic relief for a condition in which the sensory or motor system is not operating properly, one must interface the prosthetic system one way or another with the brain. A rudimentary way of doing so is to have a paralyzed individual voluntarily move a portion of his or her body that retains movement to actuate a system implanted in another part of the body, as is the case with a hand grasp implant that is operated by a shrug of the shoulder. The thought process and the neuronal firings that move the shoulder originate in the Pins and Needles in the Brain 211 brain. But shrugging the shoulder is awkward and provides minimal information as to what the user wants to do with the implanted hand device. The ideal way to take signals from and send them to the brain is to interact directly with it, which for the most part, involves implanting electrodes either on or in the brain, and therein lies the conundrum. Since the brain is the seat of all thought and the center of our being, the mind, if you will, implanting it with foreign objects is the most socially questionable facet of neural prostheses. And because the brain is far and away the most complex and least understood organ in the human body, it is the most di≈cult to safely implant. Yet despite these caveats, scientists are working to create systems that would make the implantation of the human brain commonplace among the disabled, and even more controversially, if someday the risk/benefit ratio makes it feasible, to enhance the natural abilities of the able-bodied as well. 5 in a laboratory at brown university in Providence, Rhode Island, a monkey sits in front of a computer monitor intently playing a video game. The laboratory is that of John Donoghue, the head of the department of neuroscience at Brown, and a leading brain-computer interface—or as he prefers to say, brain-machine interface—researcher. To get to Donoghue’s laboratory, one must navigate a maze of halls and stairs before arriving at a small outer room cluttered with shelves of computers and monitors, some flickering with tables and graphs as the undisturbed monkey plays away in an adjacent closet-sized room. One of the monitors is hooked up to a closedcircuit television system that can be switched to show the monkey from various angles as it performs its experimental tasks. She is seated at what in laboratory parlance is known as a ‘‘primate chair,’’ which looks something like a metal lawn chair. Her chin is cradled on a bracket, similar to the type one places one’s chin on during an eye examination. The monkey’s eyes have an almost human quality as they peer at the computer monitor in front of her. At her mouth is a rigid straw that runs from a juice bottle mounted on a wall just outside the room. The monkey is totally engaged in playing a video game in which her job 212 Shattered Nerves is to manipulate a mechanical arm in front of her—a computer mouse for monkeys—to move a red ball on the screen. The mechanical arm is a horizontal device, with a scissors joint halfway down its length, allowing it to be moved back and forth and side to side. The monkey’s goal is to get the ball to strike a...