Rapid eye movement: Difference between revisions

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In [[mammal]]s and [[birds]], [[sleep]] can be divided into two categories. In one of them, the eyes move rapidly. This is called REM-sleep (from '''rapid eye movement'''). Most dreams take place in this phase. REM-sleep occurs normally at intervals throughout the night. The periods of REM-sleep increase in length in the second half of the night. REM-sleep was first discovered in 1952-53. The function of REM sleep is not well understood.
{{DISPLAYTITLE:Rapid Eye Movement}}
'''Rapid eye movement''' ('''REM''') is a unique phase of [[sleep]] in mammals and birds, characterized by random and rapid movement of the [[eyes]], accompanied by low muscle tone and vivid dreaming. REM sleep is one of the two basic states of sleep, the other being [[non-rapid eye movement sleep]] (NREM). REM sleep is cyclic and occurs multiple times during a normal night’s sleep, with episodes becoming longer and more intense toward morning.
[[File:Sleep EEG REM.png|Sleep EEG REM|thumb]]
[[File:Sleep EEG Stage 2.jpg|Sleep EEG Stage 2(Non REM)|thumb]]
== History ==
REM sleep was first identified in the early 1950s by [[Nathaniel Kleitman]] and his student [[Eugene Aserinsky]] at the University of Chicago. In 1953, they published their findings linking rapid eye movements during sleep to the experience of vivid [[dreaming]]. Later researchers, including [[William Dement]] and [[Michel Jouvet]], expanded upon this work and helped to establish REM sleep as a fundamental stage in the [[sleep cycle]].


Professor Nathaniel Kleitman and his student Eugene Aserinsky defined rapid eye movement and linked it to dreams in 1953.<ref>Antrobus, John S. & Mario Bertini (eds) 1992. ''The neuropsychology of sleep and dreaming''. Hillsdale, NJ: Lawrence Erlbaum. ISBN 0-8058-0925-2</ref> REM sleep was further described by researchers including William Dement and [[Michel Jouvet]].<ref>[http://www.lefigaro.fr/flash-actu/2017/10/03/97001-20171003FILWWW00095-mort-de-michel-jouvet-scientifique-du-reve.php Mort de Michel Jouvet, scientifique du rêve] {{fr icon}}</ref><ref>Parmeggiani, Pier Luigi 2011. ''Systemic homeostasis and poikilostasis in sleep: is REM sleep a physiological paradox?'' London: Imperial College Press. ISBN 978-1-94916-572-2
== Characteristics of REM Sleep ==
</ref>
REM sleep is marked by:
* Rapid movement of the eyes under closed eyelids
* Brain activity similar to wakefulness, as measured by [[electroencephalography]] (EEG)
* Temporary paralysis of most voluntary muscles (atonia), preventing the body from acting out dreams
* Elevated [[heart rate]], [[respiration]], and variable [[blood pressure]]
* Vivid and often memorable dreams


The other category, where this movement of the eyes does not happen, is called NREM-sleep (Non-REM sleep). Usually, dreams do not occur during this time. There are three or four stages of NREM-sleep. Stage I is just barely sleeping, or dozing. Stage II is also light sleep. Normally, in [[adult]] humans, about half of the time spent asleep is spent in light sleep. Stages III and IV are called deep sleep. Deep sleep is necessary for growth and [[healing]]. It can be quite difficult to awaken someone who is in stage III or stage IV sleep. Sometimes stages III and IV are combined and called stage III.
REM sleep typically occurs every 90–110 minutes during sleep, with 4 to 6 cycles per night. Each REM episode can last from 5 to over 30 minutes, increasing in duration through the night.


Adult humans normally sleep in [[Sequence|cycle]]s of 90 to 110 minutes each. The night's sleep can be four or fine of these cycles. Each cycle includes, in this order: stage I, stage II, stage III (IV), stage II and REM.
== Sleep Cycles ==
A typical sleep cycle consists of the following stages:
# '''Stage I''' – Light sleep or drowsiness
# '''Stage II''' – Light sleep; body temperature and heart rate decrease
# '''Stage III''' – Deep sleep; also known as slow-wave sleep (SWS)
# '''Stage IV''' – (Sometimes combined with Stage III)
# '''REM sleep''' – Brain activity increases, and most dreams occur


The fact that birds and mammals both show REM and NREM sleep suggests that the [[trait]] evolved before the two groups diverged in their evolution. That suggests that the REM/NREM feature is both early and important in the evolution of land vertebrates.<ref>{{cite journal |vauthors=Low PS, Shank SS, Sejnowski TJ, Margoliash D | title = Mammalian-like features of sleep structure in zebra finches | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 105 | issue = 26 | pages = 9081–9086 | year = 2008 | pmid = 18579776 | pmc = 2440357 | doi = 10.1073/pnas.0703452105 | bibcode = 2008PNAS..105.9081L }}</ref>
Each cycle transitions through these stages, culminating in REM sleep. After REM sleep, the body usually returns to Stage I or II before beginning a new cycle.


== REM and dreams ==
== NREM Sleep ==
Rapid eye movement sleep is associated with [[dream]]ing. Waking up sleepers during a REM phase is a common way to get dream reports. 80% of typical people can give some kind of dream report under these circumstances.<ref>Solms 1997. ''The neuropsychology of dreams. : a clinico-anatomical study''. Mahwah, NJ: Lawrence Erlbaum, pp. 10, 34. ISBN 0-8058-1585-6 </ref> Sleepers awakened from REM tend to give longer more [[narrative]] descriptions of the dreams they were experiencing. They estimate the duration of their dreams as longer.<ref name=HobsonEtAl2000>J. Alan Hobson, Edward F. Pace-Scott, & Robert Stickgold 2000. Dreaming and the brain: toward a cognitive neuroscience of conscious states. ''Behavioral and Brain Sciences'' '''23'''.</ref><ref>Ruth Reinsel, John Antrobus, & Miriam Wollman 1992. Bizarreness  in dreams and waking fantasy. In Antrobus, John S. & Mario Bertini (eds) ''The neuropsychology of sleep and dreaming''. Hillsdale, NJ: Lawrence Erlbaum Associates. {{ISBN|0-8058-0925-2}}</ref>
[[Non-rapid eye movement sleep]] (NREM) encompasses stages I to III (or IV, depending on the classification system). During these stages:
* Eye movement slows or stops
* Muscles remain active (except during REM)
* Dreaming is less common and less vivid
* Physical restoration and [[growth hormone]] secretion occur during deep sleep


[[Lucid dream]]s are reported far more often in REM sleep.<ref name=HobsonEtAl2000 /><ref>Stephen LaBerge 1992. Physiological studies of lucid dreaming. in Antrobus & Bertini (eds) ''The neuropsychology of sleep and dreaming''. Hillsdale, NJ: Lawrence Erlbaum. ISBN 0-8058-0925-2</ref> The mental events which occur during REM usually have dream '[[hallmark]]s' including [[narrative|narrative structure]], convincingness (like waking life), and instinctual themes.<ref name=HobsonEtAl2000 />
== REM and Dreams ==
REM sleep is closely linked to [[dream]]ing. Awakening individuals during REM sleep frequently results in dream reports, with up to 80% of awakenings yielding descriptions of dream content. REM dreams tend to be longer, more detailed, emotionally intense, and story-like compared to NREM dreams.


Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder (more specifically a parasomnia) in which people act out their dreams.
'''Lucid dreaming'''—when the dreamer becomes aware that they are dreaming—occurs most frequently during REM sleep. Mental activity during REM is marked by high levels of brain activation, particularly in visual and emotional centers.


== References ==
== Evolutionary Perspective ==
{{reflist}}
The presence of both REM and NREM sleep in birds and mammals suggests that these sleep stages evolved before the divergence of these lineages. This implies that REM sleep is evolutionarily ancient and may play a critical role in neurological functions like memory consolidation and emotional regulation.


[[Category:Physiology]]
== Disorders Associated with REM Sleep ==
One significant disorder related to REM is:
* '''[[REM sleep behavior disorder]] (RBD)''': A type of [[parasomnia]] where the usual muscle paralysis of REM sleep is absent, causing individuals to physically act out their dreams. This can lead to injury to the sleeper or their partner.
 
== See Also ==
* [[Sleep cycle]]
* [[Dream]]
* [[Lucid dream]]
* [[Sleep disorders]]
* [[Electroencephalogram]]
* [[Circadian rhythm]]
 
== External Links ==
* [https://www.sleepfoundation.org/stages-of-sleep/rem-sleep REM Sleep – Sleep Foundation]
* [https://www.ninds.nih.gov/health-information/disorders/sleep-disorders NINDS – Sleep Disorders]
* [https://www.ncbi.nlm.nih.gov/books/NBK19956/ PubMed – Sleep Physiology]
{{stub}}
[[Category:Sleep]]
[[Category:Sleep]]
[[Category:Neuroscience]]
[[Category:Dreams]]
[[Category:Sleep disorders]]
[[Category:Neurophysiology]]

Latest revision as of 00:48, 3 April 2025

Rapid eye movement (REM) is a unique phase of sleep in mammals and birds, characterized by random and rapid movement of the eyes, accompanied by low muscle tone and vivid dreaming. REM sleep is one of the two basic states of sleep, the other being non-rapid eye movement sleep (NREM). REM sleep is cyclic and occurs multiple times during a normal night’s sleep, with episodes becoming longer and more intense toward morning.

Sleep EEG REM
Sleep EEG Stage 2(Non REM)

History[edit]

REM sleep was first identified in the early 1950s by Nathaniel Kleitman and his student Eugene Aserinsky at the University of Chicago. In 1953, they published their findings linking rapid eye movements during sleep to the experience of vivid dreaming. Later researchers, including William Dement and Michel Jouvet, expanded upon this work and helped to establish REM sleep as a fundamental stage in the sleep cycle.

Characteristics of REM Sleep[edit]

REM sleep is marked by:

  • Rapid movement of the eyes under closed eyelids
  • Brain activity similar to wakefulness, as measured by electroencephalography (EEG)
  • Temporary paralysis of most voluntary muscles (atonia), preventing the body from acting out dreams
  • Elevated heart rate, respiration, and variable blood pressure
  • Vivid and often memorable dreams

REM sleep typically occurs every 90–110 minutes during sleep, with 4 to 6 cycles per night. Each REM episode can last from 5 to over 30 minutes, increasing in duration through the night.

Sleep Cycles[edit]

A typical sleep cycle consists of the following stages:

  1. Stage I – Light sleep or drowsiness
  2. Stage II – Light sleep; body temperature and heart rate decrease
  3. Stage III – Deep sleep; also known as slow-wave sleep (SWS)
  4. Stage IV – (Sometimes combined with Stage III)
  5. REM sleep – Brain activity increases, and most dreams occur

Each cycle transitions through these stages, culminating in REM sleep. After REM sleep, the body usually returns to Stage I or II before beginning a new cycle.

NREM Sleep[edit]

Non-rapid eye movement sleep (NREM) encompasses stages I to III (or IV, depending on the classification system). During these stages:

  • Eye movement slows or stops
  • Muscles remain active (except during REM)
  • Dreaming is less common and less vivid
  • Physical restoration and growth hormone secretion occur during deep sleep

REM and Dreams[edit]

REM sleep is closely linked to dreaming. Awakening individuals during REM sleep frequently results in dream reports, with up to 80% of awakenings yielding descriptions of dream content. REM dreams tend to be longer, more detailed, emotionally intense, and story-like compared to NREM dreams.

Lucid dreaming—when the dreamer becomes aware that they are dreaming—occurs most frequently during REM sleep. Mental activity during REM is marked by high levels of brain activation, particularly in visual and emotional centers.

Evolutionary Perspective[edit]

The presence of both REM and NREM sleep in birds and mammals suggests that these sleep stages evolved before the divergence of these lineages. This implies that REM sleep is evolutionarily ancient and may play a critical role in neurological functions like memory consolidation and emotional regulation.

Disorders Associated with REM Sleep[edit]

One significant disorder related to REM is:

  • REM sleep behavior disorder (RBD): A type of parasomnia where the usual muscle paralysis of REM sleep is absent, causing individuals to physically act out their dreams. This can lead to injury to the sleeper or their partner.

See Also[edit]

External Links[edit]

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