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

Introduction

Introduction ∑ The marvel of the human machine unavoidably inspires awe. The coordination within the massive complex of organs that make up our bodies is nothing short of miraculous. While each organ performs its individual function , it also operates in finely tuned concert with the other instruments of the body to create the music of life. The nervous system alone, consisting of billions of neurons, or nerve cells, that allow us to perceive and interact with the world around us, makes the finest of humankind’s technological developments pale into insignificance. Even scientists who devote their entire lives to understanding the workings of the sensory systems eventually arrive at a gap they’ve been unable to bridge short of taking a leap of faith. Modern technology allows them to watch an individual’s brain waves fluctuate in response to a stimulus such as sound, light, or a pinprick. But they still can’t look at a spike in waves on an oscilloscope or changes in images on a brain scan and really understand how that stimulus translates into perception. They don’t understand how electrical activity in the brain corresponds to perception, pain, pleasure, or conscious awareness. There’s no doubt, however, that electricity is at the root of it all. Electricity , or the movement of electrons and ions, is such a fundamental aspect of nature that it was woven into the fabric of life. A long time before humankind ever walked the face of the earth, let alone thought about electronics, Mother Nature found that electrical signals provide the most e≈cient method of 2 Shattered Nerves transmitting information within the body. No living creature could survive without electricity, because the body is, in essence, an electrical machine. Without electricity, neurons could not communicate the signals that allow us to see, hear, touch, smell, taste, and move about, and even think. We need electricity to interact with the world around us as much as an electric motor requires electric power to function. Without it the motor is dead. The same holds true for human beings. Without electricity there is no life. Complete comprehension of how small spikes of electricity lead to perception and thought still lurks somewhere in the future. But scientists are making exponential leaps in understanding the mass of neurons that make up the brain and the rest of the nervous system that extends from it, though their task is akin to counting, categorizing, and understanding the activity of each star in the universe, as well as its relationship to the whole. Given this level of complexity, resulting from the vast number of elements that must operate perfectly to provide perception, movement, and thought, it is amazing that it is not the norm for things to go awry. Yet in the vast majority of people, the staggering number of components that make up the bodily systems that allow us to function in our environment work perfectly, or close to it. Unfortunately, in some people, the circuitry that generates and conducts electrical signals goes bad, rendering them unable to fully partake of the miracle of the senses, as in the case of the blind, when the rod and cone photoreceptors inside the eye can no longer translate light into the electrical signals that send information to the brain. Or when the hair cells inside the cochlea of the inner ear, which process sound waves, die o√, and a person loses the ability to hear. Failure of the body’s electrical circuitry is also responsible for paralysis that occurs when spinal cord injuries damage the nerve cells that carry electrical signals from the brain’s motor cortex to the muscles and from the skin’s tactile receptors to the somatosensory portion of the brain. Until recently, these conditions were deemed irreversible. Now there is hope. Through the ability to miniaturize integrated electronic circuitry, scientists can take concrete steps toward countering the ravages wrought on those whose internal circuitry has shorted out, without it being a total act of Introduction 3 hubris. The same methods used to shrink electronic components down to pocket computer and digital watch size are now being used to create reliable, intricate devices small enough to be implanted inside the eye, the ear, the muscles, and the brain itself. These manmade, implantable marvels of modern technology are known as ‘‘neural prostheses,’’ devices that directly interface with some component of the nervous system. They do so...