9 - Why we Sleep, Siegel, J.M.

9 - Why we Sleep, Siegel, J.M. - Article# 9 Why We Sleep -...

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Article # 9 Why We Sleep - sleep consumes 1/3 of our life What is Sleep? -sleep is marked by periods of rapid eye movement (REM) (implies that something active is happening during sleep) which alternates with non-REM sleep (aka. quiet sleep) in a regular cycle -all terrestrial mammals (that have been examined) exhibit REM sleep -most brain neurons are at or near their maximum levels of activity while one is awake, but during sleep neuronal activity is variable -the brain behaves different in REM and non-REM sleep -NON-REM SLEEP: -cells in different brain regions do different things -most neurons in the brain stem, above the spinal cord, reduce or stop firing -most neurons in the cerebral cortex and forebrain areas only reduce activity by a small amount -adjacent cortical neurons fire synchronously with a low frequency rhythm (vs. during the day when they are not synchronized) -this synchronous firing produces higher-voltage brain waves than when awake -less energy is consumed by the brain when asleep -non-REM sleep maintains normal breathing and hr -rare to have vivid dreams -a small group of brain cells at the base of the forebrain are maximally active in non-REM: called “sleep-on” neurons, responsible for inducing sleep -“sleep-on” neurons are activated by increased body heat -REM SLEEP: -brain activity in REM resembles that during waking (low voltage waves b/c neurons are performing individually) -cell in both the forebrain and the brainstem are active: they signal at rates as high, or higher than that of waking -brain consumes energy at same rate as when awake -greatest neuronal activity accompanies twitches and eye motion -REM “sleep-on” cells are in the brainstem, are very active in REM and are
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This note was uploaded on 02/05/2012 for the course BIOLOGY 3u3 taught by Professor Dr.rollo during the Spring '11 term at McMaster University.

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9 - Why we Sleep, Siegel, J.M. - Article# 9 Why We Sleep -...

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