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SLEEP. Dement and Kleitman (1930’s). Qu. How do we measure sleep?. Electro-encephalogram ( Head ) Electro-oculogram ( Eye ) Electro-myogram ( Neck ). EEG TODAY. Brain Waves and Sleep Stages. Awake. 1. 2. 3. REM. 4. 0. 1. 2. 3. 4. 5. 6. 7. Hours of sleep.

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Dement and Kleitman (1930’s)

Qu. How do we measure sleep?

  • Electro-encephalogram (Head)

  • Electro-oculogram (Eye)

  • Electro-myogram (Neck)




Qu what are the sleep stages

Awake

1

2

3

REM

4

0

1

2

3

4

5

6

7

Hours of sleep

Qu. What are the sleep stages?

EEG stages



Qu why do we sleep

Restoration Model patterns?= Sleep allows us to recharge our bodies and recover from fatigue

Evolutionary/circadian rhythm model Sleep’s main purpose is to increase a species’ chances of survival

Qu. Why do we Sleep?

  • Cognitive model = Sleep is necessary for the consolidation of memory and mental functioning.


Sleep deprivation experiments
Sleep deprivation experiments; patterns?

  • Peter Tripp radio DJ sleep deprived self for 200 hours.

  • Randy Gardner - sleep deprived for 264 hours under supervision of sleep researcher Dement


Sleep deprivation effects
Sleep deprivation effects patterns?

  • 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.


Rem rebound dement
REM Rebound - Dement patterns?

Rebound phenomena

Following sleep deprivation, we recover much of our lost sleep but there is some segregation of recovery of different types of sleep.

Following selective SWS or REM deprivation, there is selective recovery


Restoration or adaption jim horne 1999 asks

Qu patterns?. 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)?

RESTORATION OR ADAPTION?Jim Horne (1999) asks……


Restoration theories
RESTORATION THEORIES? patterns?

  • 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?


Brain development
BRAIN DEVELOPMENT patterns?

Evolutionary/circadian rhythm model

Sleep’s purpose = increase the chances of survival

Species sleep patterns are different due to….

BODY SIZE

Ecological niche


Qu. Do all animals sleep? patterns?

All mammals and birds sleep.

Qu. Can you explain these differences?


Qu do whales sleep
Qu. Do whales sleep? patterns?

Apparently so


Qu do fish sleep
Qu. Do fish sleep? patterns?

Apparently so

Fish, reptiles and amphibians have periods of ‘inactivity’



Meddis 1975 predation theory
Meddis, (1975) - patterns?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 =



  • Webb 1982 hibernation theory
    Webb, (1982) - a large killHibernation theory

    • Sleep evolved to conserve energy

    • Hibernation necessary when food resource are low.



    Qu what would happen to sleep patterns of animals who can t hunt at night
    Qu. What would happen to sleep patterns of animals who can function at night?can’t hunt at night?


    Energy consumption issues
    Energy consumption issues? can function at night?

    • 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.


    Evolutionary critiques
    Evolutionary critiques? can function at night?

    • 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?


    Cognitive theories
    COGNITIVE THEORIES can function at night?

    • 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?


    Rem and cogntition

    Cortex can function at night?

    hippocampus

    Strickgold (1999) found that PET scans reveal a high level of activity between these two structures during sleep.

    SWS - activity is one way

    REM - info flows other way

    REM and COGNTITION


    Strickgold 1999
    Strickgold (1999) can function at night?

    • 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%


    Conclusion
    CONCLUSION? can function at night?


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