Understanding Sleep: Types, Stages, Functions, and Disorders - Prof. Susan A. Anderson, Study notes of Biological Psychology

Download Understanding Sleep: Types, Stages, Functions, and Disorders - Prof. Susan A. Anderson and more Study notes Biological Psychology in PDF only on Docsity! 1/17/2011 1 Chapter 8 Sleep and Biological Rhythms Prepared by S. Anderson Unless otherwise noted, all illustrations are from Foundations of Behavioral Neuroscience, Carlson, 8/E. h tt p :/ /w w w .y e ll o w -l la m a .c o m /l e t- sl e e p in g -a n im a ls -l ie / Lecture Outline • What is sleep? • What is sleep like? • Why do we sleep? • What are some common sleep disorders? • How is the brain involved? • A biological clock? 086pics.jpg What is sleep? • Is sleep… – A behavior or a state of consciousness? – A state of consciousness or a suspension of consciousness? – An active process or a passive process? – A biological imperative? – Common to all life forms? – A state of rest for mind and body? • What are the answers to these questions? 1/17/2011 2 What is sleep like? • Two types of sleep – Slow-wave sleep (SWS) • Four stages ranging from light to deep sleep – Rapid eye movement sleep (REM sleep) h tt p :/ /w w w .y e ll o w -l la m a .c o m /l e t- sl e e p in g -a n im a ls -l ie / • EEG during wakefulness – Alpha activity • Regular waves of 8–12 Hz • Resting, eyes usually closed, not engaged in strenuous mental activity – Beta activity • Irregular, mostly low-amplitude waves of 13–30 Hz • Desynchronous – reflects the fact that many different neural circuits in the brain are active • Person is alert and attentive to events in the environment or is thinking actively 5 • Stages of slow-wave sleep – Stage 1 • Transition from sleep to waking • Some theta activity occurs – 3.5-7.5 Hz – Becoming synchronized • Transition from sleep to waking – Stage 2 • Periods of theta • Sleep spindles • K complexes • If awakened, not aware that they were sleeping 3 5 0 p x- S ta g e 2 sl e e p _ n e w .s vg .p n g 1/17/2011 5 Why do we sleep? • “Sleep is the fundamental anabolic process common to all life forms, plant and animal.”* – Anabolic – the aspect of metabolism that contributes to growth • Only warm-blooded vertebrates (mammals & birds) experience REM sleep. • Even marine mammals sleep, one hemisphere at a time. * http://www.wordiq.com/definition/Sleep D o lp h in .j p g • Function of slow-wave sleep - to permit the brain to rest – Cerebral metabolic rate and blood flow decline – Increases or decreases in exercise have little effect on sleep – Effects of sleep deprivation • Urge to sleep increases • Cognitive abilities, but not physical abilities, decline • Distorted perception and hallucinations may occur • Difficulty concentrating sl e e p -n -s tu d y .j p g 1/17/2011 6 • Function of REM sleep – to promote brain development – Effect of REM deprivation – REM rebound – Animals that are born with less mature brains show more REM sleep that those born with more mature brains – Humans • REM sleep appears at about 30 weeks after conception • Normal newborn – 70% REM sleep • By 6 months – 30% • Age 8 – 22% • Late adulthood – 15% • Sleep and learning – Sleep seems to promote the consolidation of long- term memories – SWS – declarative memories • See Figure 8.7, page 225 – REM sleep – nondeclarative memories • See Figure 8.6, page 225 What are some common sleep disorders? • Insomnia – Affects about 25% of population at least occasionally – Self-reports of insomnia are often inaccurate • Those who complain may have normal sleep • Those who don’t complain may actually have problems – Causes: • Irregular sleep habits • Use of drugs and alcohol • Aging 1/17/2011 7 • Sleep apnea – Cessation of breathing while sleeping • People are often unaware of the problem • Symptoms include snoring, headache, feelings of fatigue during the day, hypertension, memory problems – Causes • Obstructive sleep apnea – obstruction of airway by soft tissues of throat • Central sleep apnea – brain fails to signal the muscles to breath – Treatment • Continuous Positive Airflow Pressure (CPAP) cp a p 2 3 .j p g • Narcolepsy – Symptoms • Sleep attacks - an irresistible urge to sleep during the day – Lasts 2-5 minutes – Person awakes refreshed • Cataplexy – complete paralysis that occurs during waking – Often precipitated by strong emotion – See videos on MyPsychKit website • Sleep paralysis – paralysis occurring just before a person falls asleep • Hypnagogic hallucinations – vivid dreams that occur just before a person falls asleep • Narcolepsy (continued) – Symptoms seem to be an intrusion of REM sleep while awake – Cause – a hereditary autoimmune disorder h tt p :/ /w w w .y e ll o w -l la m a .c o m /l e t- sl e e p in g -a n im a ls -l ie /