1. SLEEP

2. Dement and Kleitman (1930’s) Qu. How do we measure sleep? Electro-encephalogram (Head) Electro-oculogram(Eye) Electro-myogram(Neck)

3. EEG TODAY

4. Brain Waves and Sleep Stages

5. Qu. What are the sleep stages? 01234567 4 3 2 1 Awake Hours of sleep REM EEG stages

6. Qu. Why do we Sleep? sRestoration Model = Sleep allows us to recharge our bodies and recover from fatigue sEvolutionary/circadian rhythm model Sleep’s main purpose is to increase a species’ chances of survival sCognitive model = Sleep is necessary for the consolidation of memory and mental functioning.

7. Restoration Theory zThe function of sleep is to allow body to be repaired and restored psychlotron.org.uk

8. The importance of SWS zGrowth Hormone is secreted during SWS zSassin et al found that when we sleep during the day and are awake at night the release of GH is also reversed. zThis supports the idea that GH is linked to SWS zKrueger et al (1985) found a link between lack of SWS and reduced immune functioning.

9. What is different about infant and old people sleep patterns?

10. 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.

11. 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.

12. Siegal (2003) zSome antidepressants which increase levels of monoamines such as dopamine and seratonin abolish REM sleep. zWhy might this be?

13. Plenary questions zHow is sleep measured? zWhat does Restoration theory say about the purpose of sleep? zGive two reasons why SWS is important. zWhat distinction does Oswald make about the purposes of REM and SWS? zWhat evidence supports the idea that REM sleep is linked to neurotransmitters?

14. Restoration theory zMain predictions: yDeficits in functioning during sleep deprivation yRebound following deprivation yIncrease in REM during brain growth, reorganisation & repair yIncrease in SWS during illness, recovery from injury psychlotron.org.uk

15. Restoration theory zMain predictions: zIncreased Exercise – increased sleep: zShapiro (81) Supports – How? zHorne & Minard (85) opposed – How? psychlotron.org.uk

16. zPeter Trip Video

17. Sleep deprivation experiments; zPeter Tripp radio DJ sleep deprived self for 200 hours. zRandy Gardner - sleep deprived for 264 hours under supervision of sleep researcher Dement zMay have been getting MICROSLEEP

18. Sleep deprivation effects zI.Q drop zI.Q drop - about 60 studies have confirmed that one hours loss of sleep leads to a 1-point drop in IQ. zQu. If you skip two hours sleep a night for a week to cram in more revision, how many IQ points will you have dropped? z15 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.

19. Rebound zGenerally, people catch up on sleep following deprivation yNot all lost sleep is reclaimed yAbout 70% of lost SWS and about 50% of lost REM typically recovered yOnly REM and SWS sleep is necessary psychlotron.org.uk

20. Growth & reorganisation z Reduction in sleep over lifespan z Highest in infants; highest REM in early years z Some changes in adolescence REM NREM 24 hour period Age 5yrs psychlotron.org.uk

21. Illness & injury zSleep does increase during illness and recovery from injury yTotal sleep time increases during illness yREM increases during recovery from brain injury, ECT & drug withdrawal ySWS deprivation can cause physical symptoms psychlotron.org.uk

22. COGNITIVE THEORIES zEmpsom and clark (1970) zSleep - especially REM sleep - facilitates the reinforcement of information in memory. zQu. What would happen if you were deprived of REM sleep during revision? zQu. How would you prove the theory right?

23. Stickgold (1999) zMethod: Students taught a visual discrimination task (learning to spot things in their peripheral vision). zThey had to do 25 sets in the evening, and another 25 sets in the morning - measured overall improvement. zSome were allowed to sleep normally, others were sleep deprived - some SWS, others REM sleep. zResults: Normal sleep - improved performance 40% zDeprived SWS sleep - Improved 28% zDeprived REM sleep - improved only 18%

24. Test zWhy does Michael Corke’s story strongly support restoration theory? zWhat Shapiro et al find about the effect of increased exercise? zWhat does the ‘rebound effect’ show about which types of sleep are important? z What is REM sleep important for according to Stickgold?

25. Evolutionary/circadian rhythm model Sleep’s purpose = increase the chances of survival BRAIN DEVELOPMENT BODY SIZE Ecological niche Species sleep patterns are different due to….

26. MammalHrs of sleep/day Giant Sloth Tree Shrew Cat, Hamster Mouse, rat, squirrel Hedgehog Humans, rabbit, pig Cow, Goat, Elephant Horse, Roe deer 20 15 14 13 10 8 3 2 All mammals and birds sleep. Qu. Do all animals sleep? Qu. Can you explain these differences?

27. Qu. Do whales sleep? Apparently so

28. Qu. Do fish sleep? Apparently so Fish, reptiles and amphibians have periods of ‘inactivity’

29. SWS and REM sleep patterns in mammals

30. Meddis, (1975) - Predation theory zSleep has evolved to help species adapt to threats. zPatterns of sleep diversify across species due to environmental threats posed, leading to; x Sleep pattern? zLarge predators = zSmall vulnerable animals = zAnimals who cannot see in the dark =

31. Lions can do little else but sleep for up to 2 x days after a large kill

32. Webb, (1982) - Hibernation theory zSleep evolved to conserve energy zHibernation necessary when food resource are low. zHerbivores 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. zCarnivores generally sleep for longer.

33. Evidence zComparative studies of different species generally support evolutionary view ySmaller animals tend to sleep more than larger (e.g. giraffe 1hr vs. bat 20hrs) yCarnivores sleep more than herbivores (e.g. lion 16hrs vs. buffalo 3hrs) zSome notable exceptions e.g. rabbit (small, herbivore) & human (much larger, omnivore) both sleep about 8hrs psychlotron.org.uk

34. Evidence zSleep patterns are affected by energy expenditure & availability yAnimals generally sleep more when weather is cold and food is scarce (Berger & Phillips, 1995) yHowever, no direct correlation between physical work done and sleep duration in humans (e.g. Horne & Minard, 1985) psychlotron.org.uk

35. 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.

36. Test zWhat is the purpose of sleep according to evolutionary theory? zWhy do differences in the sleep patterns of species of animal support this? zWhat did Meddis claim about the purpose of sleep? zAccording to Webb why do carnivores sleep more than herbivores?

37. Evolutionary critiques? zQu. Can these ideas be tested? zQu. Does sleep serve the same function for all species? zQu. Is sleep an ‘adaptive process’? zQu. What happens if we are deprived of sleep?

38. Problems zMany evolutionary significant factors could affect sleep patterns; theory doesn’t tell us which are important yDoes a bat get so much sleep because it’s small or because it has few predators? yWhy do animals with very different lifestyles have similar sleep patterns? psychlotron.org.uk

39. Problems zSome features of sleep cannot be explained easily by the hibernation theory: yWhy is sleep universal when in some species (e.g. dolphins) it would have been an advantage to get rid of it? yWhy is sleep deprivation apparently fatal? psychlotron.org.uk

40. RESTORATION OR ADAPTION? Jim Horne (1999) asks…… zQu. If the body can repair itself under a wakeful state, what is the main purpose of sleep, physiological repair or neurotransmitter recovery? zQu. 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)?

41. 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.

42. zHorne (1999) - asks; zQu. What is the point of falling unconscious? zQu. Is sleep is purely restorative, why are there so many variations of sleep patterns across species?

43. Task zFind 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.

44. Test zExplain why evolutionary theory contains a contradiction. zWhy is REM sleep a problem when it comes to energy conservation? zWhy can research on different species of animal sometimes be flawed? zWhat is a phylogenetic signal?