Sleep Copyright 2004 Allyn and Bacon Copyright 2004

Sleep Copyright  2004 Allyn and Bacon Copyright  2004

Sleep Copyright 2004 Allyn and Bacon Copyright 2004 Allyn and Bacon Stages of sleep awake alpha activity, regular, medium frequency 8-12 Hz (more prevalent with eyes closed); beta activity, irregular, low amplitude 13-30 Hz. stage 1 theta activity 3.5-7.5

Hz transition. stage 2 irregular, periods of theta, sleep spindles (short bursts at 12-14 Hz maintenance of sleep), Kcomplexes (1 per minute). stage 3 high amplitude delta >3.5 Hz. Copyright 2004 Allyn and Bacon REM sleep desynchronized EEG, some theta, rapid eye movements.

body largely paralyzed. Copyright 2004 Allyn and Bacon Sleep stages 90 minute cycle between REM and non-REM sleep. Copyright 2004 Allyn and Bacon Dreaming increased cerebral blood flow to visual cortex and decreased to inferior frontal.

decreased activity (decreased planning, sequencing of events) increased activity (increased, vivid imagery) Copyright 2004 Allyn and Bacon Sleep Disorders - Insomnia

Margaret Thatcher (and Winston Churchill) slept only a few hours a night! underlying cause insomnia is a symptom. medication can be a curse sleep medication hangover! sleep apnea difficulty breathing while asleep (people who snore have brief periods of apnea).

Copyright 2004 Allyn and Bacon Narcolepsy sleep attack at inappropriate times (particularly during monotonous or boring conditions). 2 5 minutes. cataplexy falling to ground - hypocretin deficiency dogs. sleep paralysis and hypnagogic hallucinations (hallucinations during the transitional state between being awake and sleeping) alien abduction?

Copyright 2004 Allyn and Bacon REM sleep behaviour disorder acting out! can be quite dangerous males dreaming their wives are being attacked will hit out at the attacker sometimes hitting their wives! women do it too failure to inhibit movement during REM. Copyright 2004 Allyn and Bacon

Slow-wave sleep usually during stage 4 sleep. nocturnal enuresis bedwetting. somnambulism sleep walking different than REM sleep acting out. pavor nocturnis night terrors. usually evident in childhood resolve naturally. Copyright 2004 Allyn and Bacon Why do we sleep?

brain rest? only warm-blooded vertebrates exhibit REM. necessary for survival? Indus Dolphin. Deal with swift currents (sleep 7 hours a day but in 4 to 60s intervals). bottlenose dolphin & porpoise sleep one hemisphere at a time! keeps one hemisphere

alert. Copyright 2004 Allyn and Bacon REM perhaps slow wave sleep is restorative but REM sleep is important for development (higher portion of REM during stages of development). consolidation OR clean up? REM sleep increases during exam time. Dont deprive yourself!

Largest increase in REM sleep associated with Copyright 2004 Allyn and Bacon largest increase in Sleep over the life span in general we require less sleep as we get older. the proportion of REM sleep needed also decreases.

Copyright 2004 Allyn and Bacon Arousal arousal level of alertness (a continuum). adenosine neuromodulator that plays a role in the initiation of sleep. Acetylcholine agonists increase EEG signs of arousal; antagonists decrease EEG signs. Norepinephrine catecholamine agonists (e.g., speed) increase arousal via noradrenergic system in the locus coeruleus. Serotonin (5-HT) increases relate to locomotion and

cortical arousal facilitating ongoing behaviours. Histamine direct effect on cortex, indirect affect via ACh induced changes. Copyright 2004 Allyn and Bacon Sleep / wake cycles ventrolateral preoptic area: A group of GABAergic neurons in the preoptic area whose activity suppresses alertness and behavioral arousal and promotes sleep. areas are reciprocally connected by inhibitory

GABAergic neurons. Copyright 2004 Allyn and Bacon Neural control of REM REM sleep is controlled by a flip-flop similar to the one that controls cycles of sleep and waking. The sleep/waking flip-flop determines when we wake and when we sleep, and once we fall asleep, the REM flip-flop controls our cycles of REM sleep and slow-wave sleep. ACh release in the dorsolateral

pons. basal forebrain connections produce arousal & cortical desynchrony. REMs arise from connections with the tectum. Copyright 2004 Allyn and Bacon Biological Clocks 90 minute activity / rest cycle 24 hour sleep / wake cycle Copyright 2004 Allyn and Bacon

Biological Clocks Biological rhythm Time frame Example Circannual Yearly Migratory cycles of

birds Infradian Less than a year Human menstrual cycle Circadian Daily

Sleep / wake cycle Ultradian Less than a day Eating cycles Copyright 2004 Allyn and Bacon Circadian Rhythms

A daily rhythmical change in behavior or physiological process. zeitgeber a stimulus (usually the light of dawn) that resets the internal clock responsible for circadian rhythms. passive response to changes in light conditions (living in Resolute would be tough). direct projections from retina provide the zeitgeber information about light. suprachaismatic nucleus (SCN) contains a biological clock that is responsible for organizing many of

2004 Allyn and Bacon the bodys circadian Copyright rhythms Seasonal rhythms breeding rhythms that begin as day lengths increase and end as they begin to decrease. pineal gland secretes melatonin during the night more produced during long nights of winter signaling the season. SADS seasonal affective disorder a decrease in melatonin levels?

light phase of the circadian rhythm may be too short. Jet lag Shift-work Copyright 2004 Allyn and Bacon Sleep movie Copyright 2004 Allyn and Bacon

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