Melanie Blower, age 11 of Sarasota, Florida, for her question:
How does the brain work?
Ordinary folk regard a giant computer with mystified amazement. However, it is designed and built by human minds and hands. Trained experts know every detail of its structure and just how it performs its mathematical miracles. They agree that, compared with the human brain, this man made computer is merely a clumsy oaf. No wonder the biologists have been unable to solve all the secrets of the human brain.
The soft brain in the human skull weighs about three pounds. It is stuffed with a whitish material and wrapped in a gray, wrinkled rind. To understand it, we cannot regard the brain as a separate item. It is the central headquarters of the body's nervous system. The entire system, including the brain, is made of sensitive nerve cells. Like all living cells, they are powered by electrochemical energy.
Biologists know more or less how an average cell works. However, the nerves are special cells that do very special work. They use electric impulses to flash messages back and forth. Millions work together in a communication system throughout the body. A network of thin nerve cells, long and short, spreads all through the body and this network is linked to the brain. The electrical energy to run the system is generated by chemical processes in the cells.
Nerve endings are sensitive to stimuli heat, sounds and dozens of things inside and outside the body. These stimuli trigger the nerves to flash messages to the brain. The nerves also respond to orders sent back from the brain. Along the way, networks of fine nerves merge and form thicker cables. Nerve cables from the eyes run directly to the brain. Cables from arms and legs and most other areas merge to form the spinal column. This main communication cable runs through the vertibrae and joins the brain near the back of the neck.
The brain itself is a dense concentration of nerve cells, each with fibers attached to a cell body. The fibers form the soft white material inside. The groovy gray rind is made of nerve cell bodies and this is where the brain performs its magic. It sifts the multitude of impulses arriving every second, interprets what they mean and decides what should be done. In less than a second, it flashes its orders back through the nervous system. These orders trigger muscles to move and all other actions of the body both conscious and unconscious. This fantastic operation is well organized. Some of the work is done by the spinal column. The brain itself has separate centers to cope with speech, taste and other departments. Opposite sides of the brain cope with opposite sides of the body. But the brain's right side controls the body's left side. Its most mysterious centers perform the miracles of reasoning and thinking.
The tongue is controlled by a center that is low down at the back of the brain. Just above it is the center that controls the jaw. There are two gray areas that neither send nor receive messages, or so it seems. Scientists suspect they may be the secret centers of reason and judgement, thought and imagination the wonders that make man kind so special. But so far, no one has been able to figure out just how these miracu¬lous talents work.