Post By : King Koil

The development of research into sleep

To conduct research on a sleeping person was just not easy till the technology caught up with the scientists, and yet scientists have been trying to study the how and why of sleep since 1875. It was British scientist Richard Caton who set the ball rolling when he discovered the electrical nature of the brain when he used a galvanometer to study electrical impulses in the brains of living animals.  He studied the brain signals of dogs and apes by placing unipolar electrodes on the cerebral cortex and the surface of the skull. He reported his findings to the British Medical Association in Edinburgh in 1875 and set the stage for Hans Berger to discover Alpha Waves in the brain. In his honour the alpha wave rhythm was also known as Berger’s Wave.

 

Recording Brain Waves

 

Hans Berger was a German neurologist and is credited with inventing the electroencephalography or EEG. It is by using the EEG that Berger was able to distinguish between the alpha waves and beta waves that the brain produced during the sleep cycle. He was the first to study the changes in the brain’s electrical impulses in the disease, epilepsy. Berger recorded the first EEG of a human being in 1926. This was a tool that was to come in very handy as scientists continued to study the brain waves both during sleep and consciousness. Recording the waves was first done on a Lippmann capillary electrometer but was not very successful, making Berger switch to using the string galvanometer. He later used the Siemens recording galvanometer that helped him record electrical voltages one ten thousandth of a volt, allowing him to measure very small electrical impulses arising in the brain. This output was then photographed by his assistant to be studied later in detail. The modern instruments that read brain waves do all this and more automatically.

 

Phases of Discovery of the Human Sleep Cycle

 

In 1937 Loomis documented the EEG patterns of Non-Rapid Eye movement or what is today called NREM sleep. This was a phenomenal breakthrough in the study of sleep opening up the sleep cycle to more detailed research.  Kleitman and Aserinsky continued this work in the University of Chicago and in 1953 were able to describe the rapid eye movement stage of sleep called REM. They then proposed connecting the REM phase of the sleep cycle with an individual dreaming at night. Kleitman continued research in the field with associate, Dement. Kleitman and Dement in 1957 were able to record and confirm the now popularly accepted stages of the human sleep cycle. This set the basic framework for all future studies into the regular sleep patterns of human beings.

 

Medical Literature Records First Sleep Disorder

 

It was with narcolepsy that the first sleep related disorder was recorded in medical literature in 1877. Narcolepsy is a chronic neurological disorder caused by the brain’s inability to regulate sleep-wake cycles normally. It usually afflicts people in the age group of 15 to 25 years. It is often undiagnosed and remains therefore untreated in the general population. It was thanks to the advent of technology that led to the building of the polysomnogram or PSG which first allowed scientists to confirm that narcolepsy was more than just a sleepy individual. The excessive daytime sleepiness, feeling of weakness, an involuntary muscle control loss, hallucinations and sleep paralysis were earlier considered individual and somewhat “put on” problems. However with the development of the multiple sleep latency test of MSLT it became evident that it was not play acting on part of an individual but an actually physiological disease that affected the patient. It was in 1880 that Gelineau first discovered a group of individuals in France who suffered from this disease. Today the combination of PSG and MSLT is used to determine if a person is suffering from narcolepsy and then referred to treatment if he is.

 

Finding the Location of the Biological Clock

 

The whole cycle of human behavior was said to stem from a circadian rhythm which was essentially controlled by a biological clock residing inside an individual. The circadian clock was the subject of great research and debate. The term ‘circadian’ comes from the Latin words for about “circa” and a day “diem”.   This is because it is not exactly registering a 24 hour day but one which can vary per individual from 22 hours to 28 hours.  The clock runs on proteins being produced in patterns as per genetic instructions passed to them. The proteins have the ability to control different functions of the person whether he is awake or asleep.

 

Some of these body functions included body temperature, heart activity, hormone secretion, blood pressure, metabolism, oxygen intake of the body and a whole lot more. It was in 1972 that studies managed to locate the suprachiasmatic nuclei (SCN) as the site of the biologic clock. This is found in the hypothalamus of the brain. The SCN consists of two tiny clusters of many thousand nerve cells. These nerve cells determine the time of the biological clock on the basis of cues from outside such as light and darkness. It then helps the local bio clocks in different organs and tissues of the body to perform as per the conditions that it has perceived.

 

Polysomnography

 

The study of sleep overnight was conducted in 1974 by Holland, who termed it polysomnography. The ability to keep subjects overnight in the lab and measure their brain waves and body functioning vital statistics has brought out many new secrets. Further research into sleep continues and surprising discoveries continue to be made as polysomnography becomes the tool of choice of scientists across the world.  Some people argue that laboratory conditions are hardly idea for studying natural sleep cycles, but the detractors of the critics say that this is not true. In truth some new facts emerge which can then be further studies and verified. Needless to say there are enough scientists, the world over, losing sleep in laboratories to make the next heady sleep research related discovery.
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