|
Rapid eye movement sleep (REM sleep, REMS) is a unique phase of mammalian sleep characterized by random movement of the eyes, low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. This phase is also known as paradoxical sleep (PS) and sometimes desynchronized sleep because of physiological similarities to waking states, including rapid, low-voltage desynchronized brain waves. Electrical and chemical activity regulating this phase seems to originate in the brain stem and is characterized most notably by an abundance of the neurotransmitter acetylcholine, combined with a nearly complete absence of monoamine neurotransmitters histamine, serotonin, and norepinepherine.〔Jim Horne (2013), “Why REM sleep? Clues beyond the laboratory in a more challenging world”, ''Biological Psychology'' 92.〕 The cortical and thalamic neurons of the waking or paradoxically sleeping brain are more depolarized—i.e., can "fire" more readily—than in the deeply sleeping brain.〔Steriade & McCarley (1990), ''Brainstem Control of Wakefulness and Sleep", §8.1 (pp. 232–243).〕 The right and left hemispheres of the brain are more coherent in REM sleep, especially during lucid dreams.〔Jayne Gackenbach, “Interhemispheric EEG Coherence in REM Sleep and Meditation: The Lucid Dreaming Connection” in Antrobus & Bertini (eds.), ''The Neuropsychology of Sleep and Dreaming''.〕 REM sleep is punctuated and immediately preceded by PGO (ponto-geniculo-occipital waves) waves, bursts of electrical activity originating in the brain stem.〔Steriade & McCarley (1990), ''Brainstem Control of Wakefulness and Sleep", §9.1–2 (pp. 263–282).〕 These waves occur in clusters about every 6 seconds for 1–2 minutes during the transition from deep to paradoxical sleep.〔Steriade & McCarley (1990), ''Brainstem Control of Wakefulness and Sleep", §1.2 (pp. 7–23).〕 They exhibit their highest amplitude upon moving into the visual cortex and are a cause of the "rapid eye movements" in paradoxical sleep.〔Subimal Datta (1999), "PGO Wave Generation: Mechanism and functional significance", in ''Rapid Eye Movement Sleep'' ed. Mallick & Inoué.〕〔 Brain energy use in REM sleep, as measured by oxygen and glucose metabolism, equals or exceeds energy use in waking. The rate in non-REM sleep is 11–40% lower.〔 == Chemicals in brain == Compared to slow-wave sleep, both waking and paradoxical sleep involve higher use of the neurotransmitter acetylcholine, which may cause the faster brainwaves. The monoamine neurotransmitters norepinephrine, serotonin and histamine are completely unavailable. Injections of acetylcholinesterase inhibitor, which effectively increases available acetylcholine, have been found to induce paradoxical sleep in humans and other animals already in slow-wave sleep. Carbachol, which mimics the effect of acetylcholine on neurons, has a similar influence. In waking humans, the same injections produce paradoxical sleep only if the monamine neurotransmitters have already been depleted.〔Ritchie E. Brown & Robert W. McCarley (2008), "Neuroanatomical and neurochemical basis of wakefulness and REM sleep systems", in ''Neurochemistry of Sleep and Wakefulness'' ed. Monti et al.〕〔Birendra N. Mallick, Vibha Madan, & Sushil K. Jha (2008), "Rapid eye movement sleep regulation by modulation of the noradrenergic system", in ''Neurochemistry of Sleep and Wakefulness'' ed. Monti et al.〕〔Aston-Jones G., Gonzalez M., & Doran S. (2007). "Role of the locus coeruleus-norepinephrine system in arousal and circadian regulation of the sleep-wake cycle." Ch. 6 in ''Brain Norepinephrine: Neurobiology and Therapeutics''. G.A. Ordway, M.A. Schwartz, & A. Frazer, eds. Cambridge UP. 157–195. Accessed 21 Jul. 2010. (Academicdepartments.musc.edu )〕〔Siegel J.M. (2005). "REM Sleep." Ch. 10 in ''Principles and Practice of Sleep Medicine''. 4th ed. M.H. Kryger, T. Roth, & W.C. Dement, eds. Elsevier. 120–135.〕 Two other neurotransmitters, orexin and gamma-Aminobutyric acid (GABA), seem to promote wakefulness, diminish during deep sleep, and inhibit paradoxical sleep.〔〔Pierre-Hervé Luppi et al. (2008), "Gamma-aminobutyric acid and the regulation of paradoxical, or rapid eye movement, sleep", in ''Neurochemistry of Sleep and Wakefulness'' ed. Monti et al.〕 Unlike the abrupt transitions in electrical patterns, the chemical changes in the brain show continuous periodic oscillation.〔Robert W. McCarley (2007), “Neurobiology of REM and NREM sleep”, ''Sleep Medicine'' 8.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Rapid eye movement sleep」の詳細全文を読む スポンサード リンク
|