Rapid eye movement sleep (REM)

For other uses, see Eye movement (disambiguation).

"REM study" redirects here. For investigations using a reflection electron microscope, see Electron microscope.

"Sentinel hypothesis" redirects here. For the hypothetical concept popularized by Arthur C. Clarke, see Bracewell probe.

Rapid eye movement sleep (REM sleep) is a normal stage of sleep characterized by the random movement of the eyes. REM sleep is classified into two categories: tonic and phasic.^[1] It was identified and defined by Nathaniel Kleitman and Eugene Aserinsky in the early 1950s.

Criteria for REM sleep includes rapid eye movement, but also low muscle tone and a rapid, low-voltage EEG; these features are easily discernible in apolysomnogram, the sleep study typically done for patients with suspected sleep disorders.

REM sleep in adult humans typically occupies 20–25% of total sleep, about 90–120 minutes of a night's sleep. During a normal night of sleep, humans usually experience about four or five periods of REM sleep; they are quite short at the beginning of the night and longer toward the end. Many animals and some people tend to wake, or experience a period of very light sleep, for a short time immediately after a bout of REM. The relative amount of REM sleep varies considerably with age. A newborn baby spends more than 80% of total sleep time in REM.^[2] During REM, the activity of the brain's neurons are quite similar to that during waking hours; for this reason, the REM-sleep stage may be called paradoxical sleep.^[3] This means there are no dominating brain waves during REM sleep.^{[citation needed]}

REM sleep is physiologically different from the other phases of sleep, which are collectively referred to as non-REM sleep (NREM sleep). Vividly recalleddreams mostly occur during REM sleep.

Info : wikipedia.org