Susan Coker, age 12, of Montgomery, Alabama, for her question:
How exactly does the brain work?
Some of us refer to man made computers as electronic brains and worry about whether they will take over all our thinking for us. No need to worry. To do most of the work done by just one human brain, a computer would have to be big enough to sprawl over most of Alabama. True, an average computer can solve highly complex math problems at fantastic speeds. But even an average human brain performs everyday duties that are beyond the best electronic brain so far imagined.
An elephant has a ten pound brain, and the brain of a giant whale weighs 20 pounds. A man's brain weighs only about three pounds, but it figures out problems, invents things, envisions beauty and creates art. No animal can write his name or draw a picture of himself. Truly the human brain is something special. It separates mankind from all other creatures and lifts him to a special place in the world of nature. Yet basically it works somewhat like the super sized whale brain or the smaller brain of a dog.
In both man and other animals, the brain is the central headquarters of the nervous system. Fibrous nerve tissues use electro chemical energy to flash messages between the brain and various parts of the body. The brain itself is made entirely of nerve cell nuclei that connect with various networks of nerve fibers and nerve endings. It is a soft mass of pasty white material with an outer layer of soft grey material. The surface of the human brain has a very thick, deeply wrinkled cortex of grey cells. Perhaps this extra grey matter enables us to out think the rest of the animal kingdom.
The brain itself is compartmentalized with centers that govern various functions. For example, the center that controls the jaw is down in back of the brain, just above the center that wags the tongue. The more thoughtful speech center is deep inside the brain. Other centers on top of the brain control arms, legs and torso. Strange to say, those that govern the right side of the body are on the left side of the brain. And an injury to the left side of the brain may damage centers that govern muscles on the right side of the body. Nerve fibers from skin, toes and limbs merge into the spinal cord which relays multiple communications somewhat like a super superior telephone cable. This major trunk line flashes messages to and from the brain. Part of it merges with a wad of nerve tissue at the base of the brain. This reliable center governs breathing, blinking and other automatic functions without help from the decision¬ making brain centers.
A detailed description of the busy brain would fill a shelf of books. And the data would be incomplete because researchers have not solved all its miraculous secrets. For example, two sizable areas of grey matter apparently neither send nor receive the usual brain waves of electrical energy. Researchers suspect that these silent centers may do calculating or perhaps carry on other miraculous brain operations.
Studying brain waves of energy is fairly new and promises to reveal many secrets. Nerve fibers to the brain are so fine that only the most powerful microscopes can trace them to various centers. This year, researchers developed new dye techniques for this work. So far they have been able to trace part of the complex network that conveys the sense of smell to special centers in the brain of a rat. Someday perhaps we can answer exactly how the brain works, down to the finest detail. But nobody can do it now.