Sleep

Question 1

Biological Explanation of Insomnia

Answer 1

• Due to the malfunctioning of certain brain chemistry
• Developed due to the prevalence of insomnia in populations who take drugs, are stressed or have existing conditions
• As all of these can be damaging to body cells

Question 2

Gregory et al

Answer 2

Increased levels of anxiety can lead to increased levels of insomnia
- EV’s controlled for

Question 3

Narcolepsy 3 Explanations

Answer 3

1) Malfunction in systems which maintain REM
2) Increase frequency of HLA antigen in the immune system
3) Low levels of hypocretin neurotransmitter

Question 4

Narcolepsy- REM explanation

Answer 4

• 1960’s
• Malfunction in the systems which maintain REM
• Vogel- REM occurred at onset of sleep in narcoleptics, and they have abnormal REM at night
• Explains some of the symptoms of the disorder which are also found in REM, eg. loss of muscle tone, hallucinations

Question 5

Narcolepsy- IMMUNE SYSTEM explanation

Answer 5

• 1980’s
• Mutation of the immune system
• Honda et al - increased frequency of human leukocyte antigen (HLA) - more than 90% of narcoleptics showed this
• HLA coordinates the immune response

Question 6

Narcolepsy- HYPOCRETIN explanation

Answer 6

• 1990’s
• Hypocretin is a neurotransmitter which regulates sleep and wakefulness
• Link between LOW levels of hypocretin and the disorder
• Lin et al- narcoleptic dogs had mutation in a gene on chromosome 12 which disrupted the way hypocretin was processed

Question 7

Narcolepsy- Mignot

Answer 7

There was no significant increased risk of one twin developing narcolepsy if the other twin had it
- So what causes the mutation on chromosome 12?

Question 8

Narcolepsy- What may cause the mutation on chromosome 12 if it is not genetics?

Answer 8

Brain injury
Infection
Diet
Stress
Auto-immune attack

Question 9

Sleepwalking- Incomplete Arousal

Answer 9

Recordings of brain activity show a mix of delta waves (SWS) and higher frequency beta waves (awake state)

A sleepwalker is in deep sleep (SWS) but is awaken, however the arousal is incomplete

Question 10

Sleepwalking Risk Factors

Answer 10

• Sleep deprivation
• Alcohol
• Having a fever
• Stress
• Psychiatric Condition
• Hormonal changes in puberty

Question 11

Two explanations for why sleep walking occurs more in children

Answer 11

1) Children have more SWS than adults
2) Oliviero- the system that normally inhibits motoractivity in SWS is not sufficiently developed in sleepwalkers. - more likely to be underdeveloped in children.

Question 12

Sleepwalking- Broughton’s study

Answer 12

The prevalence of sleepwalking in first degree relatives of a sleepwalker is 10 times greater than that for people in the general public

Question 13

Sleepwalking- Zadra et al

Answer 13

Studied 40 sleepwalkers in a sleep lab and prevented them for sleeping
1st night- 50% sleepwalked
2nd night- 90% (due to more stress from sleep deprivation)

Question 14

Infancy- Amount of sleep and percentage of REM

Answer 14

16 hours a day
50% REM
80-90% REM if premature

Question 15

Infancy- Features of sleep

Answer 15

Uncontinuous- shorter sleep cycles.

Question 16

Childhood - Amount of sleep and percentage of REM

Answer 16

12 hours a day

30% REM

Question 17

Childhood- Features of sleep

Answer 17

Experience parasomnias e.g. sleep walking and night terrors

Question 18

Adolescence - Amount of sleep and percentage of REM

Answer 18

9-10 hours a day

25% REM

Question 19

Adolescence - Features of sleep

Answer 19

Circadian rhythms shift into a PHASE DELAY where they delay sleeping and waking.

Question 20

Adulthood- Amount of sleep and percentage of REM

Answer 20

8 hours a day

25% REM

Question 21

Adulthood- Features of sleep

Answer 21

Increasing frequency of other sleep disorders e.g. insomnia

Question 22

Old Age- Amount of sleep and percentage of REM and SWS

Answer 22

8 hours a day
20% REM
5% SWS
Mostly light sleep

Question 23

Old Age- Features of sleep

Answer 23

Wake up frequently

Experience a phase advance of circadian rhythms - feel sleepier earlier and wake up earlier

Question 24

Restoration Theory- Growth Hormones

Answer 24

• Secreted during SWS

- Important for cell growth and restoration of body tissue

Question 25

Restoration Theory- Immune System

Answer 25

• Consists of protein molecules and antibodies

- Regenerated during SWS

Question 26

Evolutionary Theory- Zepelin and Rechtshaffen

Answer 26

Smaller animals sleep more than larger animals - however sloth exception (sleep for 20 hours)

Question 27

Evolutionary Theory - Allison and Cicchetti (energy conservation)

Answer 27

Larger animals had less NREM than smaller animals. NREM conserves energy, but they have less of a need for this.

Question 28

Evolutionary Theory- Allison and Cicchetti (predator avoidance)

Answer 28

Species with a high risk of predation did sleep less…however rabbit exception. They have a higher danger rating but sleep more than moles

Question 29

Evolutionary Theory- Horne

Answer 29

Core sleep- SWS, what the body requires for restorative purposes
Optional - REM and NREM- occupies unproductive hours and, in small mammals, conserves energy

Question 30

Circadian Rhythm

Answer 30

Once a day, e.g. sleep-wake cycle

Question 31

Infradian Rhythm

Answer 31

Once a month or year e.g., menstrual cycle, SAD

Question 32

Ultradian Rhythm

Answer 32

Happens a few times a day e.g. sleep cycles, eating cycles

Question 33

SCN

Answer 33

A group of neurons in the hypothalamus that have their own regular rhythms of firing activity

Question 34

Pineal Gland

Answer 34

Controlled by the SCN, secretes the hormone melatonin

Question 35

Melatonin

Answer 35

Increases feelings of sleepiness. Levels fall in light and rise in darkness

Question 36

Siffre

Answer 36

• 6 months in a cave
• Circadian rhythms settled at 25 hours
• Occasionally erratic, drastically changing to 48

Question 37

Ashchoff and Wever

Answer 37

• World war two bunker
• Most p’s had circadian rhythms of about 24-25 hours
• Some of the p’s extended to 29 rhythms

Question 38

Folkard et al

Answer 38

• 3 weeks in a cave
• Sped clock up to a 22 hour day
• They settled at a 24 hour rhythm despite this
• One participant adapted to the 22 hour

Question 39

Tilley and Wilkinson

Answer 39

Daytime sleep is often between 1-2 hours shorter than normal, with REM being particularly affected

Question 40

Knutson et al

Answer 40

Those who worked shifts for more than 15 years were 3 times more likely to develop heart disease

Question 41

Czeisler et al

Answer 41

Introduced a forward rotating shift to a Utah chemical plant workforce who were struggling with stress. After 9 months, health improved, productivity increased by 25% and there were less personnel problems

Question 42

Boivin et al

Answer 42

Artificial lighting-
Had different groups of p’s experienced different intensities of light brightness. The group with the ‘very bright light’ advanced their cycle the most, by 5 hours.

Question 43

Phase advance

Answer 43

Occurs when travelling from West to East, most severe because it shortens the day so you might have to sleep when your body arousal is high

Question 44

Phase delay

Answer 44

Occurs when travelling from East to West, least severe because it only extends the day

Question 45

Recht et al

Answer 45

Analysed baseball results over 3 years. Teams from the East travelling to the West (phase delay) won 44% of games. Teams travelling from the West to the East (phase advance) won 37% of games.