Biological Rhythms and Sleep Flashcards

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1
Q

What are the three biological causes of narcolepsy?

A

Abnormal REM sleep, a mutation of the immune system and low levels of hypocretin.

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2
Q

Why is REM sleep abnormal in narcoleptics? (Vogel)

How does this explain the disorder?

A

It occurs at the onset of sleep and is abnormal at night.

Some of the symptoms of narcolepsy, such as loss of muscle tone and hallucinations are found in REM sleep.

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3
Q

What did Honda et al find which suggests that narcolepsy is caused by the immune system?

A

90% of narcoleptics have and increased frequency of HLA, which coordinates the immune response.

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4
Q

What is the role of hypocretin?

How does it cause narcolepsy?

A

Hypocretin regulates the sleep-wake cycle with the hypothalamus.
There is a link between low levels of hypocretin and the disorder.

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5
Q

What did Lin et al find to support the role of hypocretin in narcolepsy?

A

Narcoleptic dogs had a mutation in a gene on chromosome 12 which disrupted the way that hypocretin was processed.

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6
Q

AO2 - What evidence make hypocretin the most likely explanation of narcolepsy? (2 things)

A

Findings in dogs have been replicated.

Nishino et al- humans had low levels of hypocretin in their CSF.

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7
Q

AO2- What did Mignot find which makes it difficult to explain the low levels of hypocretin?

A

There is no significant risk of both twins developing narcolepsy; the disorder is not genetic.

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8
Q

AO2- What might cause the hypocretin abnormalities?

A

Brain injury, infection, diet, stress or an auto-immune attack (this would link to HLA abnormalities by Honda et al).

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9
Q

AO2- Explain how the psychoanalytic approach would explain narcolepsy. (Lerham and Weiss)

A

Sudden onsets of sleep are a way of disguising sexual fantasies and arousal, or of coping with them and reducing anxiety and distress.

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10
Q

AO2- Why is the psychoanalytic view a minority view?

A

Narcolepsy has clear physiological element meaning that biological factors are more likely to cause it.

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11
Q

AO2- What is wrong with the explanations of narcolepsy ? (2 things)

A

They are reductionist - they reduce the disorder to a malfunction in a specific biological system = oversimplified in and artificial way.
They are deterministic - the individual cannot bring the disorder under their control.

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12
Q

AO2- What is the problem with the use of animals in narcolepsy studies? Why?

A

The findings can’t be generalised to humans as humans and animals have a different anatomy and physiology and different sleep patterns. Plus, humans have the ability to think about their experience while animals cannot, which may affect the way they sleep.

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13
Q

AO2- What is positive of using animals to study narcolepsy?

A

The findings have been replicated in humans.

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14
Q

What are the symptoms of narcolepsy?

A

Sudden and uncontrollable attacks of sleep that last 10-20 minutes. Sufferers often have cataplexy too, where they have a loss of muscle control leaving them mentally awake but physically paralysed (like REM)

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15
Q

How does ‘incomplete arousal’ explain sleep walking?

A

The sleep walker is in a deep sleep but is partly awake as the carry out activities associated with being awake. (Their brain has a mixture of Delta Waves, typical of SWS, and Beta waves, typical of waking brain)

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16
Q

What are the risk factors for sleep walking? (6)

A

Sleep deprivation, alcohol, fever, stress, psychiatric conditions and hormonal changes

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17
Q

What percentage of children sleep walk?

Why are children more likely to sleepwalk than adults?

A

20%

They have more SWS than adults.

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18
Q

What does Olivero suggest is the reason that children sleepwalk?

A

The system that inhibits motor activity during SWS is not sufficiently developed in some children and adults.

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19
Q

What did Olivero examine?

What did he find?

A

The motor excitability of adult sleep walker during wakefulness.
Sleepwalkers had signs of immaturity in the relative neural circuits.

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20
Q

AO2- What did Broughton find to show a genetic basis for sleep walking?

A

The prevalence of sleep walking in 1st degree relatives of an affected subject is 10 times greater than in the general population.

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21
Q

AO2- What did Lecendreux et al find to show a genetic basis for sleep walking?

A

A 50% concordance rate in MZ twins compared to a 10-15% concordance rate in DZ twins. They also identified a gene that may be critical in sleep walking (DQB1*05)

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22
Q

What is the diathesis-stress model?

A

An individual will have a vulnerability to a disorder due to their genes but it will only appear if triggered by a stressor.

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23
Q

AO2- What did Zedra et al do to find out if the diathesis-stress model can be applied to sleep walking?

What did they find?

What does this show?

A

They studied 40 patients in a sleep lab who were suspected of sleep walking. They prevented them from sleeping while there.
On the first night, 50% of patients showed sign of sleep walking. This rose to 90% of the second night.
> Sleep deprivation doesn’t cause sleep walking in normal individuals ; sleep deprivation = the stressor for vulnerable individuals.

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24
Q

AO2- How does the diathesis-stress model relate to children?

A

More likely to sleep walk as high levels of SWS are the diathesis.

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25
Q

AO2- What is the proposed psychological cause of sleep walking?

Why is this unlikely?

A

Acting out dreams representing repressed traumas and anxiety.

Sleep walking occurs during SWS when dreaming is not possible.

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26
Q

What waves are present during the 4 stages of NREM sleep?

A

Stage 1- Beta and alpha waves (fast and low altitude)
Stage 2- Theta waves & sleep spindles (phases of fast EEG activity that last 1 second and have K complexes)
Stage 3- Delta waves (slow and long altitude) start to appear and sleep spindles decrease
Stage 4 - Delta waves = deepest stage of NREM

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27
Q

What happens in REM sleep? (paradoxical sleep)

A

The brain and eyes are active but the body is paralysed

Beta waves are present (fast and desynchronised)

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28
Q

Why is the sleep cycle ultradian when the sleep-wake cycle is circadian? (sleep elevator)

A

There are 5 cycles of sleep each night which last about 90 minutes - this cycle occurs more than once every 24 hours.
SWS only occurs in the first two cycles. REM occurs in all and increases during the night

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29
Q

AO2 - What objective measures have been used to distinguish the stages and cycles of sleep?
Why are these more reliable than self-report?

A

EEGs -measure brain waves
EOGs -measure eye movement
EMGs - measure muscle movement
These are less subject to bias

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30
Q

AO2 -What are the problems with the sleep lab? (2)

A

It is an artificial setting - lacks ecological validity

It is reductionist - can’t reflect factors that affect sleep in real life

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31
Q

AO2- Are the findings universal?

Stages of sleep

A

Yes- stages 3 and 4 occur only in the first two cycles and and REM sleep always increases through the night.
This means that the finding have validity and are reliable

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32
Q

AO2- Why are there individual differences in the sleep wake cycle?

A

The study shows that 5 sleep cycles occur in around 8 hours but many people sleep more or less than this.

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33
Q

AO2- What is wrong with the self-report method? (2) (sleep-wake cycle)

A

It is vulnerable to bias and distortion due to researcher effects and participant reactivity. The data is also subjective and reliant on memory.

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34
Q

What happens to the amount of sleep and percentage of REM as we age?

A

The amount of sleep we have decreases from 16 hours in infancy to around 8 hours in old age. While the percentage of REM decreased from 50% of sleep in infancy to around 20% in old age.

35
Q

What do adolescents experience?

A

Phase delay. This is where circadian rhythms change so that adolescents feel more awake at night but struggle to wake early.

36
Q

What do old age people experience?

A

Phase advance. This means that they feel more tired in the evening and wake up earlier.

37
Q

AO2- What are the problems with using lab experiments in studying lifespan changes in sleep? (3)

A
  • Lacks external validity- can’t be generalised outside of the lab
  • Limited research into normal sleep patterns of middle-aged people (busy raising families/working)
  • Findings are likely to come from people with sleep difficulties - can’t generalise
38
Q

AO2- What are the problems of measuring sleep?

A

-It involves being connected to electrodes which affects the quality and quantity of sleep- can’t generalise to real life setting

39
Q

AO2- How did Webb examine individual differences? (sleep-wake cycle)
What did they find?

A

By looking at data from the same participant on different nights.
Sleep patterns may be determined by individual constitution rather than age

40
Q

AO2- Why are findings for lifespan changes in sleep culturally biased?

A

The study is based on Northern and Central European and North American adults who tend to sleep for one long period during the night. Therefore it ignores the fact that sleep may be different in countries where adults take siestas, meaning that results cannot be generalised.

41
Q

AO2- Why may the findings from sleep labs be inapplicable?

A

Many people sleep with partners and ‘co-sleep patterns’ and likely to be different from sleeping alone.

42
Q

AO2- Why is it difficult to know exactly how much sleep a person has?

A

Sleep onset is gradual and entails a sequence of events rather than a discrete event.

43
Q

What is the idea behind the Evolutionary Theory of Sleep?

A

Sleep is necessary for survival and is passed on through natural selection.

44
Q

What are the four components of the Evolutionary Theory of Sleep?

A

Energy conservation, Predator Avoidance, Foraging Requirements and Waste of Time.

45
Q

What is the Energy Conservation explanation of sleep? (Evolutionary Theory of Sleep)

A

Sleep is a period of enforced inactivity so that less energy is used and body temperature is maintained. Animals with a high metabolic rate and warm blood (mammals) have to use the most energy to maintain their body temperature.

46
Q

What is the Foraging Requirements explanation of sleep? (Evolutionary Theory of Sleep)

A

Animals whose food is low in nutrients (herbivores) must spend more time eating and less time sleeping while animals whose food is high in nutrients (carnivores) can afford to sleep more.

47
Q

What is the Predator Avoidance explanation of sleep? (Evolutionary Theory of Sleep)

A

Predators can sleep longer than prey as the prey must remain vigilant and can’t sleep when vulnerable.

48
Q

What is the Waste of Time explanation of sleep? -2 studies (Evolutionary Theory of Sleep)

A

Meddis- Prey sleeps to avoid predators when vulnerable as being still makes them less obvious
Siegel- Less likely to be injured when asleep (avoid danger)

49
Q

AO2- What did Yound find which makes it difficult to generalise the findings?

A

Out of 5000 mammal species, we only have information about the the sleep patterns of less than 150 and this information is not reliable for the amount of REM and SWS sleep.

50
Q

AO2- What evidence supports the Energy Conservation explanation? (Evolutionary Theory of Sleep)
What is wrong with this?

A

Zepellin & Rechtstaffen found that small animals with higher metabolic rates sleep more.
But there are many exceptions such as sloths which sleep for 20hours a day

51
Q

AO2- Is the importance of NREM and REM sleep.

What does this suggest about the Energy Conservation explanation? (Evolutionary Theory of Sleep)

A

Only NREM is for energy conservation, REM is for brain development. But Allison & Cichetti found that large mammals have less NREM sleep but not less REM, which suggests that the explanation is correct as they have a lower metabolism.

52
Q

AO2- What did Capellini find which goes against the Energy Conservation explanation? (Evolutionary Theory of Sleep)

A

They found no correlation between the size of a mammal and the amount of NREM sleep it has.

53
Q

AO2- What supports the Foraging Requirements explanation? (Evolutionary Theory of Sleep)

A

Phylogeny of sleep suggests that greater foraging requirements restrain the amount of time available to sleep, which was shown by Capellini et al.

54
Q

AO2- What supports the Predator avoidance explanation? (Evolutionary Theory of Sleep)
What contradicts this?

A

Allison and Cichetti found that species at risk of predation sleep less that predators.
But there are exceptions - rabbits sleep more than moles despite being at greater risk of predation.

55
Q

AO2- What is a limitation of the Waste of Time explanation? (Evolutionary Theory of Sleep)

A

Sleep seems to be too complex to be a mechanism to keep an animal still.

56
Q

AO2- What are the general evaluations of the Evolutionary Theory of Sleep?

A

+ Species that are genetically close have similar sleep patterns, which suggests that there is an evolutionary link

  • Methods used by Capellini were not standardised > can’t make meaningful comparisons between species
  • There are elements that the evolutionary theory does not explain, such as why we struggle to to stay awake without sleep when it is dangerous to sleep in the day
57
Q

What are the main symptoms of insomnia?

A

Taking >30 mins to get to sleep
Having 85% sleep efficiency
Increased night time awakeness

58
Q

What are the possible triggers of insomnia?

A

exams, relationships , starting a new job and other stressful events

59
Q

What are the two categories of insomnia?

What do these mean?

A

Primary insomnia - have no other conditions
Secondary insomnia- have pre-existing conditions such as depression, anxiety, heart failure and drug use. These may cause insomnia

60
Q

What is the behavioural explanation of insomnia?

A

It is learnt through classical and operant conditioning.
Classical - a stressor triggers an inability to sleep, creating an association between bedtime cues and lack of sleep
Operant- when person is unable to sleep in the future, the association is reinforced

61
Q

What is the cognitive explanation of insomnia?

A

It is caused by faulty cognitive processes (incorrect belief that they won’t be able to sleep)- may also be due to maladaptive beliefs and depression
Belief causes insomniac to feel anxious before bed, triggers fight or flight response, making them to alert to sleep

62
Q

What is the biological explanation of insomnia?

A

It is caused by damaged or malfunctioning brain chemistry - is more common among highly stressed populations.
May be due to taking drugs and alcohol as this damages body cells

63
Q

What evidence is there to suggest that insomnia is a psychological problem? (support for behavioural and cognitive )

A

+ Behavioural approach produces successful therapies

+CBT is successful > changing thought processes stops insomnia > explanation is accurate

64
Q

What support did Gregory et al find for the cognitive explanation?
What is good about this study?
What is bad?

A

+High levels of anxiety led to increased prevalence of insomnia
+High internal validity- controlled EVs (gender, health and psychological problems)
-Correlation- cause or effect?

65
Q

What support did Heath et al find for the cognitive explanation?

A

+ People who had higher scores on the neuroticism scale had higher incidences of insomnia

66
Q

Why are the psychological explanations of insomnia reductionist?

A

They attempt to explain a complex disorder in a simplistic way and they ignore the input of genetic factors such as ‘clock genes’

67
Q

Why is the methodology used to test psychological explanations of insomnia limited?

A

The methods are ideographic - findings depend on individuals memory so are unreliable.
Demand characteristics -findings might be artificially high or low
Ethnocentric- Western countries studied

68
Q

What is the idea behind the Restoration Theory of sleep?

A

Sleep is necessary for growth and repair: SWS is for growth and repair of the body; REM is for growth and repair of the brain

69
Q

How are SWS and Growth hormone related?
Why is this important according to the Restoration
Theory?
What did Sassin et al find?

What support is there for the role of Growth hormone in the restoration theory?

A

Growth hormone is released during SWS.
Growth hormone allows body to grow and is most important in Childhood.
When sleep cycles are reversed by 12 hours, the release of growth hormone is reversed > GH is produced during SWS only
+Van Couter & Plat: amount of GH released decreases as we age which correlates with reduced SWS

70
Q

How is the immune system related to SWS according to the Restoration Theory?

A

SWS is necessary for the effective functioning of the immune system as it affects protein synthesis
Kreuger et al- poor immune system = more likely to get ill- lack antibodies

71
Q

Why is REM sleep needed for brain growth according to the Restoration Theory?

A

The more immature the offspring, the longer they sleep - dolphins have nearly no REM sleep, while platypus sleep for 8 hours.

72
Q

Why is REM sleep important for memory according the Restoration Theory?

  1. According to Crick and Mitchison?
  2. According to Stickgold?
A
  1. Unwanted memories are discarded during REM to allow useful memories to be consolidated.
  2. REM allows procedural memories to be consolidated while SWS allows semantic and episodic memories to be consolidation
73
Q

What evidence contradicts findings for the growth and repair of the body for the Restoration Theory?

A

Should need more sleep after exercise to replace proteins and nutrients used.
But - Horne and Miriad: people do not sleep for any longer after exercise > Ps fell asleep faster after exercising but not for longer > other reasons for sleep

74
Q

What does the Restoration Theory suggest will happen to the body and the brain if it faces sleep deprivation?

A

They will be unable to grow and repair so they will suffer

75
Q

What studies have been carried out into the effects of sleep deprivation? (Restoration theory)

A
  • Peter Tripp: stayed awake for 200 hours for a radio show > his core body temp dropped, he suffered hallucinations and became aggressive & had psychological symptoms – sleep is vital for normal functioning
  • Randy Gardener: stayed awake for 11 days > faced no significant side effects – Tripp may have already had issues
76
Q

What are the issues with the studies into sleep deprivation? (Restoration Theory)

A
  • Methodological issues: case studies - can’t generalise due to small sample size & Ps are unique (few people are willing to give up sleep)
77
Q

Explain Rechstaffen et al’s study. (Restoration Theory)
Positives
Limitations

A

Kept rats awakes by jolting them when they started to fall asleep. After 33 days, all sleep deprived rats died
+suggests sleep is needed to function
-may have died due to the stress of the procedure
-can’t generalise to humans
-Contradictory evidence > Rattenborg et al: similar studie on pigeons. All survived and unaffected by lack of sleep

78
Q

What is a positive of the Restoration Theory? (I/A/D)

A

Explains why people struggle to stay awake after lack of sleep- need sleep for brain growth and repair

79
Q

What is a negative of the Restoration Theory? (I/A/D)

A

Does not explain evolutionary links to sleep - e.g. why do dolphins have no REM despite being intelligent animals? Should still need some for brain repair

80
Q

What does Horne suggest about the Restoration Theory? (I/A/D)

A

Both Evolutionary theory and Restoration theory are correct - core sleep is for Restoration & optional sleep is for evolutionary reasons

81
Q

What do Endogenous Pacemaker and Exogenous Zeitgeber mean?

A
EP= internal cues which maintain body rhythms
EZ= external 'time-giver' e.g light, clock.
82
Q
Define these phrases:
-Ultradian
-Circadian
-Infradian
Give examples
A
  • Ultradian = takes less than 24 hours for 1 cycle - sleep cycle oscillations
  • Circadian= 1 cycle takes 24 hours- sleep-wake cycle
  • Infradian= takes more than 24 hours for 1 cycle- menstrual cycle and Seasonal Affective Disorder
83
Q

Give examples of cave studies used to test the role of endogenous pacemakers and exogenous zeitgebers

A

Reinberg: women spent 3 months in a cave (had miner’s lamp) –> days lengthened to 24.6hrs and menstrual cycle shortened to 25.2 days = more than 1 pacemaker
Siffre: spent 3 trips to caves (no zeitgebers but had dim light) –> day always lengthened e.g left cave on 17th August and thought it was 20th September= controlled by pacemaker but influenced by zeitgebers
Folkard: tried to override internal clock by putting 12ps on a 22hour clock in a cave for 3 weeks–> would not decrease
Aschoff and Weaver: Ps in WWII bunker with no cues –> circadian rhythms were 24-25hours

84
Q

What are the problems with cave studies?

A
  • case studies: can’t generalise; individual differences (morning person vs night person) and lacks ecological validity
  • artificial lights: Czeisler et al - it’s possible to change circadian rhythms from 22 hours to 28 hours using a dim light –> can’t alter rhythms with zeitgebers to certain extent