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| rapid eye movement sleep | |
|---|---|
| Name | REM sleep |
| Other names | Paradoxical sleep |
| Duration | 5–20 minutes per cycle |
| Frequency | Every 90–120 minutes |
| Onset | After NREM stages |
| Neural structures | Pons; locus coeruleus; basal forebrain; thalamus |
| Neurotransmitters | Acetylcholine; serotonin; norepinephrine; GABA |
| First described | 1953 |
rapid eye movement sleep is a distinct sleep stage characterized by rapid saccadic movements of the eyes, low-amplitude mixed-frequency electroencephalographic activity, muscle atonia, and vivid dreaming. It cycles across the night in mammals and birds and is associated with specific patterns of brain activation and autonomic variability. Researchers from institutions such as Harvard University, University of Oxford, Stanford University, Massachusetts Institute of Technology, and University College London have advanced understanding through polysomnography, lesion studies, and pharmacological experiments.
REM sleep was first described in 1953 and later termed paradoxical sleep due to wake-like cortical activity alongside muscle paralysis. Characteristic features include rapid eye movements detected by electrooculography, low-voltage mixed-frequency EEG similar to wakefulness, and generalized skeletal muscle atonia mediated by brainstem circuits. The stage is associated with autonomic fluctuations in heart rate and respiration observed across studies at Johns Hopkins University, Columbia University, University of California, Los Angeles, University of Cambridge, and Yale University. REM episodes lengthen across the night, often peaking in the early morning hours and are temporally organized within ultradian cycles first mapped by investigators at National Institutes of Health laboratories.
REM sleep generation depends on reciprocal interactions among pontine, mesopontine, and forebrain regions. Key nuclei include the pontine tegmentum, locus coeruleus, dorsal raphe nucleus, pedunculopontine nucleus, laterodorsal tegmental nucleus, and ventrolateral preoptic area—structures studied in work from Salk Institute, Max Planck Institute for Brain Research, Brown University, Karolinska Institutet, and University of Toronto. Cholinergic activation from the pedunculopontine and laterodorsal tegmental nuclei promotes cortical desynchronization, while monoaminergic withdrawal from the dorsal raphe and locus coeruleus enables REM atonia via glycinergic and GABAergic interneurons. The thalamocortical system and hippocampus show distinctive oscillations during REM, with theta rhythm implicated in memory processing in studies at Princeton University, University of California, San Diego, Duke University, University of Michigan, and Columbia University. Genetic and optogenetic manipulations in model organisms by teams at Massachusetts Institute of Technology and Cold Spring Harbor Laboratory have mapped cell-type specific contributions to REM regulation.
REM sleep is predominant in newborns and declines with age, a developmental trajectory documented by pediatric and sleep centers at National Health Service, Children's Hospital of Philadelphia, Cincinnati Children's Hospital Medical Center, Boston Children's Hospital, and Great Ormond Street Hospital. Infants may spend up to half their sleep time in REM-like active sleep, supporting sensory and neural circuit maturation. Across childhood, adolescence, adulthood, and aging, the proportion and continuity of REM shift, with aged populations showing reduced REM duration and altered REM architecture noted in cohort studies at Mayo Clinic, Karolinska University Hospital, Cleveland Clinic, University of Pittsburgh Medical Center, and Samsung Medical Center.
REM sleep has been implicated in emotional processing, procedural and spatial memory consolidation, synaptic plasticity, and the regulation of affective networks. Landmark experiments at MIT, Harvard Medical School, New York University, University of California, Berkeley, and University of Pennsylvania linked REM to performance improvements on motor skill tasks and to the modulation of fear memory reconsolidation. Neuroimaging from National Institute of Mental Health, NIH Clinical Center, Imperial College London, University of Zurich, and Weizmann Institute of Science demonstrates activation of limbic structures, including the amygdala and anterior cingulate, during REM. Hypotheses originating from investigators at Columbia University, University of Cambridge, and Stanford University propose roles in synaptic downscaling, predictive coding, and emotional homeostasis; controversies persist and are actively tested.
REM-related disturbances include REM sleep behavior disorder, narcolepsy with cataplexy, REM sleep without atonia, and REM-related breathing disorders. Clinical characterization and longitudinal studies have been conducted at Mayo Clinic, University of Innsbruck, University of Barcelona, Osaka University, and University of Copenhagen. REM sleep behavior disorder is a prodromal marker for synucleinopathies such as Parkinson's disease and Lewy body dementia, with neurodegenerative links explored by centers at University of Toronto, University of California, San Francisco, and Karolinska Institutet. Narcolepsy type 1 involves hypocretin/orexin neuron loss implicated by research at Université de Paris, University of Tokyo, Pitié-Salpêtrière Hospital, and Scripps Research. REM abnormalities also appear in mood disorders, post-traumatic stress disorder, and psychotic illnesses investigated by teams at McGill University, King's College London, University of Melbourne, and University of Hong Kong.
Polysomnography remains the gold standard, combining EEG, EOG, EMG, and cardiorespiratory channels in sleep laboratories at Stanford Sleep Medicine Center, Cleveland Clinic Sleep Disorders Center, Royal Brompton Hospital, Flinders Medical Centre, and Guy's and St Thomas' NHS Foundation Trust. Actigraphy, home sleep testing, intracranial recordings, functional MRI, PET, and computational modeling by groups at ETH Zurich, University of California, Irvine, Riken Institute, McLean Hospital, and University of Illinois Urbana-Champaign complement laboratory measures. Animal models in laboratories at Max Planck Institute for Ornithology, University of Oxford, University of Wisconsin–Madison, and Princeton Neuroscience Institute permit cellular-resolution interrogation via optogenetics, chemogenetics, and calcium imaging.
REM expression is highly sensitive to pharmacological agents. Antidepressants such as selective serotonin reuptake inhibitors and monoamine oxidase inhibitors suppress REM, documented in trials at Mayo Clinic, Johns Hopkins Medicine, Mount Sinai Health System, and McLean Hospital. Cholinergic agonists and antagonists, GABAergic hypnotics, orexin receptor antagonists, and adrenergic modulators alter REM propensity; clinical pharmacology work has been carried out at Pfizer Research, Roche, GlaxoSmithKline, Eli Lilly, and Novartis. Understanding drug effects on REM informs treatment of narcolepsy, depression, and insomnia, with regulatory and clinical studies coordinated by agencies and centers including Food and Drug Administration, European Medicines Agency, World Health Organization, National Sleep Foundation, and American Academy of Sleep Medicine.
Category:Sleep stages