SLEEP Dement and Kleitman (1930s) Qu. How do we measure sleep? Electro-encephalogram Electro-oculogram Electro-myogram (Head) (Eye) (Neck)
EEG TODAY Brain Waves and Sleep Stages Qu. What are the sleep stages? Awake 1
EEG stages 2 3 REM 4 0 1
2 3 4 5 Hours of sleep
6 7 Qu. Why do we Sleep? Restoration Model = Sleep allows us to recharge our bodies and recover from fatigue Evolutionary/circadian rhythm model Sleeps main purpose is to increase a
species chances of survival Cognitive model = Sleep is necessary for the consolidation of memory and mental functioning. Restoration Theory psychlotron.org.uk
The function of sleep is to allow body to be repaired and restored The importance of SWS Growth Hormone is secreted during SWS Sassin et al found that when we sleep during the day and are awake at night the release of GH is also reversed. This supports the idea that GH is linked to SWS Krueger et al (1985) found a link between
lack of SWS and reduced immune functioning. What is different about infant and old people sleep patterns? Oswald (1983) Found that tissue growth in skin takes place more quickly when we are asleep. REM sleep is important for brain growth & repair. SWS important for
bodily growth & repair. (1969) Patients recovering from drug overdoses. Significant increase in quantity of REM sleep which is indicative of recovery processes. Siegal and Rogawki (1988) Sleeping may be a way of conserving & replenishing brain chemicals known as neurotransmitters. Over the day these levels fall. During REM
sleep neurons synthesize new neurotransmitter for release during waking. Siegal (2003) Some antidepressants which increase levels of monoamines such as dopamine and seratonin abolish REM sleep. Why might this be?
Plenary questions How is sleep measured? What does Restoration theory say about the purpose of sleep? Give two reasons why SWS is important. What distinction does Oswald make about the purposes of REM and SWS? What evidence supports the idea that REM sleep is linked to neurotransmitters? Restoration theory
Deficits in functioning during sleep deprivation Rebound following deprivation Increase in REM during brain growth, reorganisation & repair Increase in SWS during illness, recovery from injury psychlotron.org.uk Main predictions:
Restoration theory Main predictions: Increased Exercise increased sleep: Shapiro (81) Supports How? Horne & Minard (85) opposed How? psychlotron.org.uk
Peter Trip Video Sleep deprivation experiments; Peter Tripp radio DJ sleep deprived self for 200 hours. Randy Gardner - sleep deprived for 264 hours under supervision of sleep researcher Dement
May have been getting MICROSLEEP Sleep deprivation effects I.Q drop - about 60 studies have confirmed that one hours loss of sleep leads to a 1-point drop in IQ. Qu. If you skip two hours sleep a night for a week to cram in more revision, how many IQ points will you have dropped? 15 x points - your STM is very poor, you cannot
think in complex ways and you loose your flexible thinking for creative answers - you are on auto-pilot. Rebound Not all lost sleep is reclaimed About 70% of lost SWS and about 50% of lost REM typically recovered Only REM and SWS sleep is necessary
psychlotron.org.uk Generally, people catch up on sleep following deprivation 24 hour period 5yrs REM NREM
Age Reduction in sleep over lifespan Highest in infants; highest REM in early years Some
changes in adolescence psychlotron.org.uk Growth & reorganisation Illness & injury Total sleep time increases during illness REM increases during recovery from
brain injury, ECT & drug withdrawal SWS deprivation can cause physical symptoms psychlotron.org.uk Sleep does increase during illness and recovery from injury COGNITIVE THEORIES Empsom and clark (1970)
Sleep - especially REM sleep facilitates the reinforcement of information in memory. Qu. What would happen if you were deprived of REM sleep during revision? Qu. How would you prove the theory right? Stickgold (1999) Method: Students taught a visual discrimination task (learning to spot things in their peripheral vision). They had to do 25 sets in the evening, and another 25
sets in the morning - measured overall improvement. Some were allowed to sleep normally, others were sleep deprived - some SWS, others REM sleep. Results: Normal sleep - improved performance 40% Deprived SWS sleep - Improved 28% Deprived REM sleep - improved only 18% Test Why does Michael Corkes story strongly support restoration theory? What Shapiro et al find about the effect of
increased exercise? What does the rebound effect show about which types of sleep are important? What is REM sleep important for according to Stickgold? Evolutionary/circadian rhythm model Sleeps purpose = increase the chances of survival BRAIN DEVELOPMEN
T Ecological niche Species sleep patterns are different due to.
BODY SIZE Qu. Do all animals sleep? Mammal Giant Sloth Tree Shrew Cat, Hamster Mouse, rat, squirrel Hedgehog
Humans, rabbit, pig Cow, Goat, Hrs of sleep/da y 20 15 14 13
10 8 3 2 All mammals and birds sleep. Qu. Can you explain these differences?
Qu. Do whales sleep? Apparently so Qu. Do fish sleep? Apparently so Fish, reptiles
and amphibians have periods of inactivity SWS and REM sleep patterns in mammals Meddis, (1975) - Predation theory Sleep has evolved to help species adapt to threats.
Patterns of sleep diversify across species due to environmental threats posed, leading to; Sleep pattern? Large predators = Small vulnerable animals = Animals who cannot see in the dark = Lions can do little else but sleep
for up to 2 x days after a large kill Webb, (1982) - Hibernation theory Sleep evolved to conserve energy Hibernation necessary when food resource are low. Herbivores tend to eat large quantities of low nutrition food e.g grass and therefore need to eat a lot of the time
less time for sleep. Carnivores generally sleep for longer. Evidence Comparative studies of different species generally support evolutionary view Some notable exceptions e.g. rabbit (small, herbivore) & human (much larger, omnivore) both sleep about 8hrs
psychlotron.org.uk Smaller animals tend to sleep more than larger (e.g. giraffe 1hr vs. bat 20hrs) Carnivores sleep more than herbivores (e.g. lion 16hrs vs. buffalo 3hrs) Evidence Animals generally sleep more when weather is cold and food is scarce
(Berger & Phillips, 1995) However, no direct correlation between physical work done and sleep duration in humans (e.g. Horne & Minard, 1985) psychlotron.org.uk Sleep patterns are affected by energy expenditure & availability Energy consumption issues?
Marine mammals do not show REM sleep, perhaps because relaxed muscles are incompatible with the need to come to the surface to breathe. In dolphins and birds, only one brain hemisphere enters SWS at a time the other remains awake.
Test What is the purpose of sleep according to evolutionary theory? Why do differences in the sleep patterns of species of animal support this? What did Meddis claim about the purpose of sleep? According to Webb why do carnivores sleep more than herbivores? Evolutionary critiques?
Qu. Can these ideas be tested? Qu. Does sleep serve the same function for all species? Qu. Is sleep an adaptive process? Qu. What happens if we are deprived of sleep? Problems Does a bat get so much sleep because its small or because it has few
predators? Why do animals with very different lifestyles have similar sleep patterns? psychlotron.org.uk Many evolutionary significant factors could affect sleep patterns; theory doesnt tell us which are important Problems
Why is sleep universal when in some species (e.g. dolphins) it would have been an advantage to get rid of it? Why is sleep deprivation apparently fatal? psychlotron.org.uk Some features of sleep cannot be explained easily by the hibernation
theory: RESTORATION OR ADAPTION? Jim Horne (1999) asks Qu. If the body can repair itself under a wakeful state, what is the main purpose of sleep, physiological repair or neurotransmitter recovery? Qu. If REM is for neurotransmitter recovery, why do infants spend 50% of their sleep in REM, but by the first
year they have half of that (when most learning occurs)? Horne (1988) Core sleep consisting of SWS & REM is essential for normal brain functioning. Stages 1-3 NREM sleep are not essential. During core sleep the brain recovers & restores itself, but bodily restoration occurs during optional sleep & periods of relaxed
wakefulness. Horne (1999) - asks; Qu. What is the point of falling unconscious? Qu. Is sleep is purely restorative, why are there so many variations of sleep patterns across species? Task Find one supporting and one
opposing piece of evidence for each of the evolutionary purposes of sleep use page 154 to 155 and write down your findings. Test Explain why evolutionary theory contains a contradiction. Why is REM sleep a problem when it comes to energy conservation? Why can research on different species
of animal sometimes be flawed? What is a phylogenetic signal?
Bill . Gallo MBA. Associate Director for Insular Area Support. Office of State, Tribal, Local and Territorial Support. Centers for Disease Control and Prevention. 300 Ala Moana Blvd. Room 8-125. Honolulu HI 96850. office: 808 541 3760. cell: 404 319...
The asymptotic variance of ???should be no greater than that of ??2. An estimator ? of the semiparametric model is call semiparametric efficient if there exists a parametric submodel??0⋅such that the asymptotic variance of ???0equals that of ?.
Sheffield Blitz - The Marples Hotel Single biggest loss of life took place in the Marples Hotel, on corner of Fitzalan Square/ High Street. On night of 12 December 1940, over 70 people were sheltering in the cellar there. At...
CAUSAL ARGUMENT] When bald and golden eagles, vultures, bears, endangered California condors and other scavengers eat the innards, called gutpiles, that hunters leave in the field after cleaning their catch or the game that hunters wound but don't capture, they...