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2 2 sleep as an evolved adaptation

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Unformatted text preview: sible for keeping us awake ► during during sleep, sleep, adenosine levels decrease M. Bassil PSYC 202 Why Why Do We Sleep? (2) (2) Sleep as an Evolved Adaptation Evolutionary/circadian sleep models: sleep’s main purpose is to increase species’ chances of survival survival in relation to its environmental demands (a predator or a prey, food requirements,…) To To small prey animals, it’s more adaptive to sleep more (e.g. Mice, Squirrels, Humans, Horses, Deer, Zebra) (e.g. OR OR it’s a mechanism for conserving energy (When asleep, asleep, metabolic rate 10-25% slower) 25% M. Bassil PSYC 202 18 Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com) 11/4/2009 Why Do We Sleep? (3) Sleep & Memory Consolidation: Specific stages may have specific functions. When awakened from REM, brain fights back to W hen get it ► REM-rebound effect (tendency to increase (tendency amount amount of REM sleep & slow wave sleep after deprivation) Memory consolidation: gradual process by which brain brain transfers information into long-term memory term during during REM BUT not well supported ► Antidepressant drugs BUT Antidepressant suppress REM, yet memory abilities are unimpaired M. Bassil PSYC 202 Sleep Disorders Insomnia: chronic chronic difficulty in falling asleep, staying asleep, or experiencing restful sleep (very (very common, afflicts 10-40% of populations) Causes: genetic, medical conditions, mental genetic, disorders (anxiety & depression), drugs, general (anxiety drugs, worrying, stress, poor lifestyle habits, circadian disruptions (jet lag & night-shift work) (jet Nondrug treatment: stimulus control: associate stimulus associate stimuli in sleep environment with sleep not waking activities (guidelines Table 6.2) (guidelines M. M. Bassil PSYC 202 19 Create PDF files without this message by purchasing novaPDF printer (http://www.novapdf.com) 11/4/2009 Sleep Disorders Narcolepsy (extreme daytime sleepiness & sudden, (extreme uncontrollable sleep attacks ► seconds to hour) When sleep attacks ► may go right into REM (which W hen may intrudes intrudes into waking consciousness) Cataplexy (sudden loss of muscle tone often triggered by (sudden excitement excitement & strong emotions) Accident prone, quality of life feels impaired, Accident misdiagnosed misdiagnosed as having a mental disorder Causes: Genetic predisposition Treatment: stimulant drugs, daytime naps, & stimulant antidepressant antidepressant drugs (suppress REM) M. Bassil PSYC 202 Sleep Disorders REM-Sleep Behavior Disorder: loss of muscle tone that that causes normal REM-sleep paralysis is absent ► dream content matches behavior (causes are unknown) Sleepwalking: stage 3 or 4 period of slow-wave sleep; wave Stare blankly, unresponsive, & awaken in morning with with no memory Afflicts 10-30% children, less than 5% adults Causes: iinherited, stress, alcohol, illnesses & medications… nherited, Treatment: psychotherapy, hypnosis, awaken children before typical typical time, create s...
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