Abbreviation for ‘rapid-eye movement sleep, referred to also as paradoxical or active sleep, and one of the five EEG sleep stages identified by the eyes moving side-to-side underneath the lids and by electrophysiological wave signals emitted by the brain that are relatively fast, short in height, and somewhat erratic (as is heart rate and breathing during this stage). It is also a sleep stage in which an organism is likely to be dreaming. Discovered by Eugene Aserinsky (1921-1998) and Nathaniel Kleitman (1895-1999) in 1953 through studying the sleep of infants.
See Active sleep, Behavioral state concept, Locus coeruleus (or ceruleus), NREM sleep, REM sleep