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REM sleep is so physiologically different from the other phases of sleep that the others are collectively referred to as Non-REM sleep.
During a night of sleep, a person usually has about four or five periods of REM sleep, which are quite short at the beginning of the night and longer at the end. It is common to awake for a short time at the end of a REM phase. The total time of REM sleep per night is about 90-120 minutes.
Physiologically, certain neurons in the brain stem, known as REM sleep-on cells, are particularly active during REM sleep, and are probably responsible for its creation. The release of certain neurotransmitters, the monoamines ( norepinephrine, serotonin and histamine) is completely shut down during REM. For this reason, the motor neurons are not stimulated by the brain's activity and the body's muscleskeletal muscle Muscle is one of the four tissue types. The other three types are: epithelium, connective tissue and nervous tissue. The primary purpose of muscle tissue is to contract. Muscle contraction is used to move parts of the body, as well as to ms don't move.
REM sleep also occurs in other mammalSubclass Monotremata Monotremata Subclass Marsupialia Didelphimorphia Paucituberculata Microbiotheria Dasyuromorphia Peramelemorphia Notoryctemorphia Diprotodontia Subclass Placentalia Xenarthra Dermoptera Desmostylia Scandentia Primates Rodentia Lagomorps. It appears that the amount of REM sleep per night in a species is closely correlated with the developmental stage of newborns. The platypusThis article is about the monotreme mammal. For the genus Platypus see ambrosia beetle. Also, Platypus is the name for a side project featuring John Myung, from Dream Theater, Derek Sherinian, former Dream Theater member, Ty Tabor, from King's X, and Rod, whose newborns are completely helpless and undeveloped, has 8 hours of REM sleep per night; in the dolphinThis article is about the dolphin mammal. For other uses of the term, please see dolphin (disambiguation). See article below. Dolphins are certain aquatic mammals related to whales and porpoises. The word is used in a few different ways. It can mean: #any, whose newborns are almost completely functional at birth, there is no or almost no REM sleep.
The function of REM sleep is not understood; several theories have been advanced. According to one theory, memoriesFor computer memory, see computer storage. Memory is one of the activities of the human mind, much studied by cognitive psychology. It is the capacity to retain an impression of past experiences. There are multiple types of classifications for memory base are consolidated during REM sleep. However, the evidence seems scant; in people that have no REM sleep (because of brain damage or drugs) memory functions are not affected. Another theory has it that the monoamine shutdown is required so that the monoamine receptors in the brain can recover to regain full sensitivity. Indeed, if REM sleep is repeatedly interrupted, the person will "make up" for it with longer REM sleep at the next opportunity. Interrupting REM sleep can improve certain types of depressionIt is common to feel sad, discouraged, or "down" once in a while, and anyone in this state might say they are suffering from depression. But for some people, this mood persists. For depression, or any other condition, to be termed "clinical" it must reach, and depression appears to be related to an imbalance of certain neurotransmitters. According to a third theory, the REM sleep of newborns provides the neural stimulation necessary to form mature neural connections; hence maturely born animals don't need much of it. Supporting this theory is the fact that the amount of REM sleep decreases with age.
The association between dreaming and REM sleep was discovered by Eugene Aserinsky and Nathaniel Kleitman in 19531953 is a common year starting on Thursday (click on link for the calendar). Events January events January 7 President Harry S. Truman announces the United States has developed a hydrogen bomb. January 13 Marshal Josip Broz Tito chosen President of Yugosl.