Somnology

Sleep research studied the behavior and all physical processes and conscious processes during sleep, and the interaction between sleep and wakefulness and sleep and the environment. There are basic research ( Chronobiology, metabolism, brain activity, dreams, learning processes ), Clinical Research ( sleep disorder ) and applied research ( shift work).

Somnology is a more general term to refer to the science of sleep, which includes not only the sleep research and sleep medicine belongs. A scientist who deals with this area is called Somnologe.

Sleep research as a science is a relatively young branch of medicine. It was created only after the REM stage (Rapid Eye Movement) was discovered during sleep of people in the 1950s. The World Health Organization distinguishes 88 different sleep disorders in their International Classification of Diseases. These are in addition to the fundamentals of the sleep-wake regulation object of study of sleep research.

Example, it was discovered that people react similarly when they are awakened during the REM ( dream sleep). They are, depending on the content of the dream, fast growing and can remember a dream. With the awakening from a deep sleep, however, the awakening is difficult, and the subjects are not so often recall dream content. Today it is known that both the nonREM and the REM sleep phases are significantly involved in the long-term storage of memory contents.

The different stages of sleep it can be seen by measuring the brain waves, muscle activity and eye movement and analyzed visually or computerized. REM sleep is characterized by rapid volley -like horizontal eye movements, paralysis of the muscles ( inability to move ), high brain activity and occasional convulsions.

History

For a long time it was assumed that sleep was a recovery period in which the brain would simply be "turned off". Consequently, it held the sleep for homogeneous and further considerations appeared uninteresting. In the middle of the 19th century changed all that noise could wake sleeping, so could not be completely shut off the brain. The tests to determine the " depth of sleep " from the beginnings of quantitative research of sleep are associated with the name Ernst Kohlschütter and its release for "measuring the strength of sleep ." His " Weckreizmethode " from 1862 chose the strength of the stimulus that leads to awakening and is called the awakening threshold, the measure of the depth of sleep. The Weckreizmethode uses a pendulum hammer that strikes a thick slate as acoustic Weckreiz. Carbon Schütters "sleep depth curve" showed an increasing depth of sleep at the beginning of sleep over the period in which, according to new perspectives on the first sleep cycle, and a decrease in the depth of sleep from then until towards morning.

Further investigations of sleep has enabled the development of electroencephalography (EEG ). Using the Hans Berger, head of neurology at the State Hospital Jena, 1924 provided an important basis for the Somnology Using EEG were in neurological research and medical diagnostic measurements of the electrical activity of the brain by recording the voltage fluctuations at the head surface possible, which is crucial in the context of sleep stages. Together with other methods is the EEG part of the most comprehensive method of investigation in the sleep lab, polysomnography.

An important next step was to identify sleep stages using the EEG. Alfred Lee Loomis to sleep researchers classified sleep stages, then called the A to E, based on the characteristics found in the EEG, such as sleep spindles. The description of the characteristics is still based on the classification of sleep stages. A and B correspond to what is currently referred to as sleep stage N1, C is now N2, D and E are now N3. REM sleep was not described. This classification was later adapted several times, first by the addition of REM sleep.

Eugene Aserinsky, a graduate student at Nathaniel Kleitman at the University of Chicago could show sections during sleep with rapid eye movements and higher brain activity in the EEG, which occurred in dreams. Thus, REM sleep was discovered. Aserinsky and Kleitman in 1953 published their findings in the journal Science.

Alexander Borbély has published research on models of sleep regulation.