BRAIN NEVER SLEEPS

Evening Star, Issue 22689, 1 July 1937, Page 18

BRAIN NEVER SLEEPS

ym* — r " NIGHT OPERATORS " ON WATCH BATTERIES OF THE NERVES The brain never sleeps. When this is said, it must be understood'that the brain and the nerves are one, and the nerves can never be at complete rest, writes Mr E. S. Grew, in the London ‘ Observer.’ They are part of a system so varied and vast that if all the telephone wires of the world were led to one exchange the arrangement would be simplicity itself compared with that of the brain and the nerve fibres conveying messages to or froni it. The brain contains the telephone exchange for these messages, and there are always night operators on watch. Their activities may be curtailed while the body sleeps. There are next to no messages or outgoing impulses from the brain aloug the nerves to the muscles. Only a few come from the body’s skin, muscles, or organs, along another set of fibres to the brain. In deep sleep most of these are shut off almost as if something drugged the operators at relaying functions. The heart and the lungs carry on at a reduced rate and must nave some impulses to send or receive. But outside these a constant flow of energy arrives from the nerve cells and at the brain exchange, and was till! a few years ago unsuspected. It has long been known that every impulse, whether coming from the brain or going to it, is accompanied by a release or electrical energy. Lift a finger and an electric discharge travelling along the nerves is registered in the brain. Every nerve fibre is a tiny battery producing a few thousandths of a volt. Where thousandths could be measured 10 years ago, millionths can be measured now. Because of this refinement of measurement, another kind of electrical nerve discharge has thrust itself on attention, and is now receiving a great deal of notice. These nerve discharges were • quite different from those of the muscle reactions of the bending finger, or those accompanying the sensations of heat or cold or pain. They did not arise from the workings of the tireless heart or the indefatigable lungs. They were something quite independent of these and different from them. They appeared to flow out from the covering of the brain. They were brain waves. They begin in the cradle, they end, we suppose, with the grave. Many observations of them have been made since Hans Berger, of Vienna, discovered them three years ago, and they do not all agree. The first observers declared there were different kinds of brain waves, and different types. There were regular trains of waves, trains broken by sharper waves, trains of less ampliture of wave, and trains of random waves. A kind of sharp wave appeared only in children, another wave in deep sleep. In infants the waves appeared in cycles of three to four a second, in children eight to 10 a second, in adults the average was 14 a second. The feature common to them all was that they manifested themselves only when the body slept. Presumably they are masked in waking hours by other electric discharges in the brain. These observations have stood the test of much experiment, though their interpretation changes. Sleep being a necessary condition of their occurrence, the American inquirers who have taken up the waves assiduously have been at pains to attain the right environment. The subject sleeps in an electrically-screened room with electrodes on his forehead and on the crown or back of his head. As he will have to be awakened at intervals of a minute and then let fall sleep again for further demonstration, he has to be sleepy. He is, therefore, kept awake for 50 hours before the experiments begin. Such is the devotion of American experimenters to the cause of science.

Repeated experiments of this kind have shown always the same forms of brain activity. When a person is going to sleep regular trains of waves persist for some time, becoming less and less frequent as drowsiness increases, and gradually changing to a random distribution of waves of no particular regularity. After some time these random waves are interrupted by sudden bursts of sharper waves. In some (persons these mark deep sleep. The random waves are those of ordinary sleep. If the sleeper is disturbed the sharp waves vanish, the regular wave trains reappear, gradually losing their regularity and again becoming random as sleep again takes hold. The rhythms of the waves are altered by various happenings. Snoring does not interfere with them, though a snore may start a different train. Coughing, rustling of the bedclothes, a closing door may affect them, and it is an odd fact that anxiety or emotional disturbance before sleep begins will upset the experiments. These are some of the collected facts about brain waves. Explanation of their origin asks more questions than can yet be answered.

When the power house of the brain is 'not active, its dynamos seem to be still purring. The brain waves are a sort of overflow output of its resting state. But because that is evident it must be drawing electric impulses from the millions of nerve cells outside it, and perhaps inside it, which are living their own lives and are developing a noticeable activity when they might be sleeping. They cannot rest and in the silent watches of the night they join together in a common demonstration of their forces,, adding contributions of their own to the brain’s reservoir of energy.