Sleep and Waking - Physiological Psychology - Lecture Slides, Slides of Physiology

Download Sleep and Waking - Physiological Psychology - Lecture Slides and more Slides Physiology in PDF only on Docsity! 1 Sleep and Waking D ig ita l V is io n/ G et ty Im ag es Docsity.com Sleep Deprivation Trivia • Peter Tripp stayed awake for 201 hours in 1959. • Guinness Book of Records record is 18 days, 21 hours, 40 minutes. • Sleep deprivation implicated in Three Mile Island, Exxon Valdez, Challenger and Bhopal disasters. 2 Ti m e Li fe P ic tu re s/ G et ty Im ag es Docsity.com Individual Variations • “Larks” are morning people. • “Owls” are night people. • Many people are in between these extremes. • Most adolescents are temporarily owls. 5 Docsity.com Results of Disruptions in Sleep Cycles • More errors occur on evening and night shifts. • Shift workers average 1.5 hours less sleep, and are more prone to sleep-related illnesses and psychological disorders. • Jet lag – Symptoms: fatigue, irritability – Conflict between internal biological clock and external zeitgebers in new surroundings – Adjustment to jet lag requires about 1 day per time zone crossed. 6 Docsity.com Adjustments to Phase Delays Are Easier than Phase Advances 7 Docsity.com SCN Activity and Light/Dark Cycles • The SCN is active during the day in both diurnal and nocturnal animals. • The SCN tells the animal whether it’s day or night, but not how to behave. • Transplants of SCN establish donor rhythms in recipient animals. 10 The SCN tells an animal the difference between night and day, not whether it’s time to sleep or be awake. Docsity.com Origin of the Internal Clock • Oscillations of protein production and degradation serves as the “ticking” of the internal clock (takes about 24 hours). • Light may participate in the triggering of some of these protein fluctuations. 11 Docsity.com Protein Fluctuations and Fruit Fly Circadian Rhythms 12 Proteins: - per - tim - Clock Docsity.com Evaluating Sleep and Wakefulness • Electroencephalogram (EEG) • Evaluation of muscle tone • Evaluation of eye movement 15 © Lester Lefkowitz/CORBIS Docsity.com Stages of Waking and Sleeping • Wakefulness is characterized by relatively desynchronized alpha and beta waves. • Slow-wave sleep (SWS) is characterized by relatively synchronized theta and delta waves. • 90–120 minute cycles characterize both sleep and wakefulness. • Ultradian cycles 16 Docsity.com EEG During Wakefulness and Sleep • Awake – alpha and beta waves • Rapid-eye-movement sleep (REM) - active EEG, eye movements and muscular paralysis • Stage 2 - Sleep spindles and K complexes • Stages 3 and 4 - larger percentages of delta waves. 17 Docsity.com Sleep Patterns Across the Lifespan • REM sleep is more prevalent in infancy. • Aging is associated with drops in overall sleep and proportion of SWS. 20 Docsity.com Dreaming • Dreams occur during both SWS and REM. • REM dreaming is more vivid, less logical, story-like and longer. • Calvin Hall found that we usually dream about familiar places and routine activities, but unfamiliar people. 21 Docsity.com Theories of Dreams • Hobson-McCarley: Dreams incorporate ongoing functions (e.g. vestibular activity) and/or environmental events (e.g. your alarm clock). • Crick-Mitchison: Dreaming is a way to forget irrelevant information. • Winson’s evolutionary approach: Animals integrate memories and experience while dreaming. 22 Docsity.com Reasons for Sleep • Benefits of REM sleep – Birds and mammals (except the echidna) show REM. – REM increases after learning has occurred – Brain development: REM more frequent in young – Contradictory findings: • Sometimes REM deprivation causes irritability • Sometimes it improves mood in depressed patients 25 Docsity.com Bremer’s Experiments Locus coeruleus: _Reticular formation: participates in participates in vigilance wakefulness Basal forebrain: participates Thalamus Superior } in SWS colliculus Raphe nuclei: inhibit reticular formation forebrain): continuous normal cycling among SWS, Cerveau isolé (isolated Encéphale isolé (isolated brain): SWS. REM, and waking states. 26 Docsity.com The Control of Wakefulness • Reticular formation • Locus coeruleus (norepinephrine) • Raphe nuclei may promote sleep by inhibiting the reticular formation 11 - 27 Docsity.com Summary of Sleep Control Stage of Arousal or Sleep Wakefulness Slow-wave sleep Rapid-eye-movement sleep Brain Areas That Initiate or Maintain Stage Reticular formation; locus coeruleus Basal forebrain; raphe nuclei Neurons in caudal reticular formation Brain Areas That Inhibit Stage Raphe nuclei Pons Raphe nuclei; locus coeruleus 30 Docsity.com Sleep Disorders • Dyssomnias involve difficulties with the initiation, maintenance, timing and quality of sleep. • Parasomnias involve unusual behaviors that intrude on normal sleep. Docsity.com • Narcolepsy – Sleep attack: • an irresistible urge to sleep during the day, after which the person awakes feeling refreshed. – Cataplexy: • complete paralysis that occurs during waking. – Sleep paralysis: • paralysis occurring just before a person falls asleep. – Hypnopompic hallucinations – Hypgogic hallucinations. 32 Sleep Disorders © Bettm ann/C O R BIS Docsity.com