Sleep

Question 1

In what ways can sleep be measured?

Answer 1

Electro…

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

Question 2

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

Answer 2

The first-night phenomenon.

Question 3

What are pre-sleep alpha waves?

Answer 3

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

Question 4

What are sleep spindles?

Answer 4

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

Question 5

What is a K complex?

Answer 5

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

Question 6

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

Answer 6

increases

Question 7

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

Answer 7

decreases

Question 8

How long are sleep cycles?

Answer 8

90 minutes.

Question 9

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

Answer 9

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

Question 10

Is there a dream-real time difference?

Answer 10

No, dream time correlates with real time.

Question 11

After the first cycle of sleep, what happens physiologically?

Answer 11

• Lack of core movement/muscle tone.

- Periods of REM sleep associated with dreaming.

Question 12

Why is REM sleep associated with dreaming?

Answer 12

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

Question 13

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

Answer 13

Recuperation and evolutionary.

Question 14

What is the main premise of recuperation theories of sleep?

Answer 14

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

Question 15

What are the main ideas behind evolutionary theories of sleep?

Answer 15

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.

Question 16

What are the main criticisms of recuperation theories?

Answer 16

• 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.

Question 17

What are the main criticisms of evolutionary theories of sleep?

Answer 17

• 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.

Question 18

What are the main points concerning animal sleep?

Answer 18

• 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.

Question 19

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

Answer 19

• It causes physiological/behavioural disturbances.

- After deprivation, missed sleep must be regained.

Question 20

What did Cirelli (2006) find?

Answer 20

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

Question 21

What did Curcio et al (2006) find?

Answer 21

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

Question 22

What does Dement (1978) point out?

Answer 22

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

Question 23

What did Webb and Agnew (1967) find?

Answer 23

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

Question 24

What did Brunner et al (1990) state?

Answer 24

That deprivation of REM causes a transient rebound.

Question 25

Are there any cognitive or emotional effects of REM deprivation?

Answer 25

No.

Question 26

What are the main brain areas involved in sleep?

Answer 26

• The hypothalamus

- The reticular system

Question 27

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

Answer 27

• 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.

Question 28

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

Answer 28

• 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.

Question 29

What is narcolepsy?

Answer 29

Periods of sudden sleep with loss of muscle tone.

Question 30

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

Answer 30

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