8/18/2023 0 Comments Rem sleep versus deep sleep![]() ĭuring REM sleep, electrical connectivity among different parts of the brain manifests differently than during wakefulness. Human theta wave activity predominates during REM sleep in both the hippocampus and the cortex. The cortical and thalamic neurons in the waking and REM sleeping brain are more depolarized (fire more readily) than in the NREM deep sleeping brain. ![]() An important element of this contrast is the 3–10 Hz theta rhythm in the hippocampus and 40–60 Hz gamma waves in the cortex patterns of EEG activity similar to these rhythms are also observed during wakefulness. Electroencephalography during REM deep sleep reveals fast, low amplitude, desynchronized neural oscillation (brainwaves) that resemble the pattern seen during wakefulness, which differ from the slow δ (delta) waves pattern of NREM deep sleep. Although the body is paralyzed, the brain acts as if it is somewhat awake, with cerebral neurons firing with the same overall intensity as in wakefulness. REM sleep is called "paradoxical" because of its similarities to wakefulness. Physiology Electrical activity in the brain Techniques of neurosurgery, chemical injection, electroencephalography, positron emission tomography, and reports of dreamers upon waking, have all been used to study this phase of sleep. Subjects allowed to sleep normally again usually experience a modest REM rebound. Many experiments have involved awakening test subjects whenever they begin to enter the REM phase, thereby producing a state known as REM deprivation. REM sleep was further described by researchers, including William Dement and Michel Jouvet. In 1953, Professor Nathaniel Kleitman and his student Eugene Aserinsky defined rapid eye movement and linked it to dreams. The body abruptly loses muscle tone, a state known as REM atonia. Organisms in REM sleep suspend central homeostasis, allowing large fluctuations in respiration, thermoregulation and circulation which do not occur in any other modes of sleeping or waking. REM sleep occurs 4 times in a 7 hour sleep. The transition to REM sleep brings marked physical changes, beginning with electrical bursts called "ponto-geniculo-occipital waves" ( PGO waves) originating in the brain stem. As sleep cycles continue, they shift towards a higher proportion of REM sleep. REM and non-REM sleep alternate within one sleep cycle, which lasts about 90 minutes in adult humans. The absence of visual and auditory stimulation ( sensory deprivation) during REM sleep can cause hallucinations. REM sleep is physiologically different from the other phases of sleep, which are collectively referred to as non-REM sleep (NREM sleep, NREMS, synchronized sleep). Experiences of REM sleep are not transferred to permanent memory due to absence of norepinephrine. 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 norepinephrine. The REM phase is also known as paradoxical sleep ( PS) and sometimes desynchronized sleep or dreamy sleep, because of physiological similarities to waking states including rapid, low-voltage desynchronized brain waves. Rapid eye movement sleep ( REM sleep or REMS) is a unique phase of sleep in mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. "The longer you spend in deeper sleep, the more refreshed you'll feel in the morning," she says.EEG of a mouse that shows REM sleep being characterized by prominent theta-rhythm But, in general, people alternate among several different levels of non-REM and REM sleep every night. Krahn says not everyone goes through all of the stages. ![]() "They're paralyzed, and that's actually felt probably to be a rinsing function - to clear the brain of toxins and byproducts that have collected during the waking day."ĭr. "Things speed up except a person cannot move," says Dr. The final stage is REM sleep, which is typically when you dream. "And that just allows the body a chance to recover from the busy day." "When we're in deep sleep, our heart rate and our breathing really slows down," says Dr. Krahn says the three types of non-REM, which stands for rapid eye movement, include level one, which is light sleep level two, intermediate sleep and level three, deep sleep. ![]() Lois Krahn, a Mayo Clinic sleep medicine specialist.ĭr. "We basically divide sleep into wake, non-REM - three types - and REM sleep," says Dr. When your head hits the pillow, your body can go through several stages of sleep. Journalists: Broadcast-quality video pkg (1:00) is in the downloads. ![]()
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