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Flashcards in Sleep Deck (30)
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1
Q

In what ways can sleep be measured?

A

Electro…

  • encephalogram (EEG)
  • oculargram (EOG)
  • myogram (EMG, neck).
2
Q

Why is it difficult to measure sleep on the first night of a study?

A

The first-night phenomenon.

3
Q

What are pre-sleep alpha waves?

A

Bursts of 8 - 12Hz activity in low amplitude high frequency waves

4
Q

What are sleep spindles?

A

1-2 second bursts of 12-14Hz waves in stage 2

5
Q

What is a K complex?

A

Single large upward then downwards deflection (like a stage 4 wave) in stage 2.

6
Q

Sleep is progressive and ____ in amplitude through the 4 stages of N-REM.

A

increases

7
Q

Sleep is progressive and ____ in frequency through the 4 stages of N-REM.

A

decreases

8
Q

How long are sleep cycles?

A

90 minutes.

9
Q

What do we do whilst asleep that we don’t recall, and why don’t we remember it?

A

Short bursts of wakefulness, don’t remember due to memory consolidation effect.

10
Q

Is there a dream-real time difference?

A

No, dream time correlates with real time.

11
Q

After the first cycle of sleep, what happens physiologically?

A
  • Lack of core movement/muscle tone.

- Periods of REM sleep associated with dreaming.

12
Q

Why is REM sleep associated with dreaming?

A

Because you’re 80% more likely to remember dreams if woken during REM.

13
Q

What are the two main types of theories of the function of sleep?

A

Recuperation and evolutionary.

14
Q

What is the main premise of recuperation theories of sleep?

A

Being awake disrupts homeostasis, which is restored by sleep, e.g. it restores energy levels.

15
Q

What are the main ideas behind evolutionary theories of sleep?

A

Sleep evolved in humans to prevent accidents and predation at night - it’s an unnecessary evolutionary atavism related to vulnerability and time spent eating.
e.g. predators have a low risk of predation and can easily satisfy feeding needs, therefore they characteristically sleep for long periods - Lions will sleep for 2 days after a kill.

16
Q

What are the main criticisms of recuperation theories?

A
  • Animal sleep (fish, species difference, sloths)
  • Exercise has little effect on sleep duration in humans (Youngstedt and Kline, 2006).
  • We don’t regain missed sleep.
17
Q

What are the main criticisms of evolutionary theories of sleep?

A
  • Sleep deprivation is fatal in animals (rats on moving platform, postmortem showed swollen adrenal glands, gastric ulcers and internal bleeding - Rechtschaffen 1993)
  • Predation risk and eating habits can at most explain 60% of species variation.
  • Sleep is universal therefore must have some function.
18
Q

What are the main points concerning animal sleep?

A
  • Fish, reptiles and amphibians don’t sleep, they just have periods of inactivity.
  • The large species difference in sleep suggest it’s not related to size or temperature.
  • Sloths hardly move but need to sleep 20hrs/day.
19
Q

What predictions do recuperation theories make about the effects of sleep deprivation?

A
  • It causes physiological/behavioural disturbances.

- After deprivation, missed sleep must be regained.

20
Q

What did Cirelli (2006) find?

A

Sleep deprivation influences mood, physiological function and molecular function. Supports recuperation theories.

21
Q

What did Curcio et al (2006) find?

A

That sleep deprivation has various effects on executive function: assimilating changing information, updating plans and reference memory.

22
Q

What does Dement (1978) point out?

A

That people recover well after sleep deprivation, e.g. Randy Gardener was awake for 260hrs and recovered after 14hrs sleep.

23
Q

What did Webb and Agnew (1967) find?

A

That preventing REM makes the body want it more - it’s the body’s default as it’s easier to maintain.

24
Q

What did Brunner et al (1990) state?

A

That deprivation of REM causes a transient rebound.

25
Q

Are there any cognitive or emotional effects of REM deprivation?

A

No.

26
Q

What are the main brain areas involved in sleep?

A
  • The hypothalamus

- The reticular system

27
Q

What has research shown about the role of the hypothalamus in sleep?

A
  • Von Economo studied brains of people who’d died from encephalitis lethargica - difficulty sleeping = anterior region damage, difficulty staying awake = posterior region damage.
  • Saper et al (2001) confirmed with lesion studies in animals.
28
Q

What has research shown about the role of the reticular system in sleep?

A
  • Bremer (1936) found that a cerveau isole transection = only SWS, and an encephale isole transection = normal cycle, therefore wakefulness area between the two.
  • Mouzzi and Morgan (1949) found that stimulation of sleeping cats’ reticular formation woke them up.
29
Q

What is narcolepsy?

A

Periods of sudden sleep with loss of muscle tone.

30
Q

What is the problem with REM sleep without core muscle atonia?

A

It can cause sleepwalking or a lot of movement whilst dreaming, which can be dangerous.