THE WAVES OF THE BRAIN

Hawke's Bay Herald-Tribune, Issue 119, 5 June 1937, Page 11

THE WAVES OF THE BRAIN

Batteries of The Nerves

BRAIN never sleeps. When this 13 said it must beunderatood that the brain and the nerves are oue, and the nerves can never "be at cdmplete test, writes Mr E. S. Grew in" the London Observer. They are jpart of a -system so varied and vast that if all the telephoue wires of the wbrld were led to one exehange the arrangement "would be simplicity itself compaTed with that of the brain and the nerve fibres conveying messages to or from it. * The brain contains the telephone exehange for these messages, and there are always night operators on watcli. Their activitics may ,.be .curtailed whilo the body sleeps. There are next to no messages or outgoing • impulses from the brain along the nerves to the muscles. Onlv a few come from the body's skin, museles, or prgans;-" along uiioch er set of fibres to the brain. In deep sleep most of these are- shut olf almost as if something drugged the operators at xelaying junctions. . • The heart and the lungs carxy on at a xeduced rate and must havo some impulses to send or reeeive. But outside these a constant flow of energy arrives from the nerve cells and at the brain exehange, and was till a few years ago unsuspected. It has long been known that everv impulse whether coming from the brain or going to it is accompanied by a iclease of electrical energy. Lift a finger and an electric discharge travelling along the nerves is Tegistered in the brain. Every nerve fibre" is r tiny battery producing a few thousandths of a volt. Wliere^. thousandths could be measured ten years ago, millionths can be measured now. Because of this xefinement of measurement another land of 'electrical nerve discharge has thrust itself on attention, and is now receiving a great deal of notice. These nerve discharges wero quite different from those of the musele reactiona of the bending linger, or those accompanying the sensations of heat cold or pain. They did not arise from the workings of the tireless heart of the indefatigable lungs. They were something quito independent of these and different from them. They appeared to flow ottt from the covering of the brain. They were brain waves. They begin in the eradle, they end we suppose with the grave. Many observations of them have been made sincc Hans Berger, of Vien31a, discovered them three years ago, and they do not all agree. The first obsorvcrs declared there wero different hinds of brain waves, and different types. There wero regular trains of wave3, trains brohen by sharper waves trains of less amplitude of wavo, and trains of random waves. A kind of sharp wave appeared only in children, another wave in decp sleep. Tn infants the -waves appeaTed in eycles of tfiree to four a second, in children eiglit to ten a "second, in adults the average wap fourteen a second. The feature common to them all was that they ' manif ested themselves _ only when the body slept. Presumably they are masked In waking hours by other electric dischages in the brain. These observations have stood 'the test of much experimont, though their interpretation changes. * * "

Sleep being a necessary condition of their occurrence, the American enqurore who have taken up the waves assiduously have been at pains to attain the rigbt environment. The subject sleepL in an electrically , screened room with dlectrodes , on his forehead and on the crown or. back of his. head. I As he will have to be awakened at intervals. of a minute and then let fall sleep again for further demohstfation, lie' has to bo sleepy. He is' therefore kept awake for fifty liours before the experimenls begin. Such'is' the devOtion of American exporimenters to " the cause of science. Repeated , experiments of this kind have shown, always the same forms o1"' brain activity. When a person is going to sleep Tegular trains of waves persist for some. time, becoming less and less fre-quent as drowsiness increases, and gradually changing to a random distribution of waves of no particulav regularity. After some time tbese random waves are interrupted by sudden bursts of sharper waves. In some persons these mark deep sleep. The random waves are those or 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 rhytlims of the waves are altered by various happenings. Snoring does not interfcre with them, though a snore may start a different train. Coughing, rustling of the bedelothcs, a closing door may affect them, and it is an odd fact that- anxiety or eraotional disturbance before sleep begins will upset the experiments. These are some of the collected facts about brain waves. Explanation of their origin usks more questions than can yet be answered. When the powcr house of the braf.n is not aetive, 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 dr'awing electric impulses from the millions of nerve cells outside it, and perhaps insido it, whi'ch are living their own lif e* " and ' are 'developing a noticeable activity when they might be sleeping. They c'annot rest anitth-the-silent watches of the -night they join. togetlier.ih a. common d.emonstrhtion of their forces, "adding ; contributions of their own ,tbi -the ; brain *,3 : T$sefybir of^ energy. ". In a restless universe, the cells of thought and action can never be entireIv ' still. ' But it seems from what has been discovered about thetee uuceasing waves, as if the conibined action of the nerve cells only by a common action of the cells acting together, but that it orises like a pulse of the nervous system. The system has its own beat, even as the heart has.