L3 Sleep Deprivation

Question 1

What are some reasons for sleep deprivation?

Answer 1

Stress/anxiety
Environment
Drugs
Blue light
Shift patterns
Age
Young children in the family
Sleep disorders/health conditions
Lifestyle

Difficult to control for everything

Question 2

How much sleep do we need?

Answer 2

There are so many individual differences, and chronotype preferences
There is not a set amount as it varies between each person

Question 3

What is sleep deprivation?

Answer 3

Actively stopping sleep by going to sleep late, getting up early etc. - often broken down into 3 types

Different to insomnia!! which is a struggle to get to sleep and maintain sleep - but they have very similar negative effects

Question 4

What are the 3 types of sleep deprivation?

Answer 4

TSD = ST <45 hours, LT >45 hours - it is difficult to run studies with TSD due to micro-sleeps and ethics
PSD = can be acute (a few days) or chronic (years)
Sleep fragmentation = wake up a lot and keep entering stage 1 sleep instead of deep sleep - don’t feel well rested the next day

Question 5

What are some signs of SD?

Answer 5

irritable, low energy, slower cognitive ability, difficulty making simple decisions, falling asleep, still hungry after eating, emotional, weakened immune system

Question 6

How does SD affect the reproductive system?

Answer 6

If a young male is sleep deprived then he will have similar testosterone levels to a man in his 80s. The quality of sperm is also similar

Question 7

What did Van Dongen et al. (2003) do to investigate cognitive function?

Answer 7

had 4 groups assessed in different SD conditions:
1. TSD 2. Slept for 8 hrs
3. Sleep restricted to 6 hrs 4. Sleep restricted to 4 hours
Had multiple measures of cognitive function to make it a stronger design (psychomotor vigilance test, digit symbol substitution task, serial addition subtraction task, Stanford sleepiness scale)

Question 8

What was seen in the psychomotor vigilance test?

Answer 8

Was good for this kind of study as there are no practice effects
The TSD group had the most errors with the 8 hour sleep group performing the best
As sleep reduced, performance got worse

Question 9

What was seen in the digit symbol substitution task?

Answer 9

The TSD group ended up with a negative total value due to the number of errors. The more sleep they had the better the performance

Question 10

What was seen in the serial addition subtraction task?

Answer 10

Showed very similar results to previous tasks, making the results more reliable

Question 11

What was seen in the Stanford sleepiness scale?

Answer 11

Subjective self-report of sleepiness. TSD are quite good at detecting the fact that they’re sleep deprived
But at 4/6hours they were not as good at detecting this

This has implications for sleep deprived drivers who think they’re fine

Question 12

What was seen in stage 2 differences?

Answer 12

Those with less total sleep spent less time in stage 2, we naturally sacrifice this stage

Question 13

What could be seen in deep sleep differences?

Answer 13

Very similar across groups, serves an important function and the body is reluctant to sacrifice this stage

Question 14

What was seen in REM differences?

Answer 14

Had small reduction but not as significant as stage 2 reductions

Question 15

What is the relevance of delta power?

Answer 15

Delta power is much greater when you’re sleep deprived - it is linked to SWS and process S

When you are sleep deprived, sleep pressure continues to build so you spend more time in deep sleep

Question 16

How did Yoo et al. (2007) investigate SD and emotional well-being?

Answer 16

assigned individuals age 18-30 to either a sleep deprivation group (awake for 35 hours) or a control group (normal sleep)
Shown a series of stimuli, starting with +ve images and getting more and more -ve whilst also measuring fMRI responses

Question 17

What was found from Yoo et al. (2007)

Answer 17

Both groups showed that the amygdala was activated when viewing the negative stimuli
The SD group activity of the amygdala was 60% greater than the control group - specifically in relation to negative images

Question 18

What happens in the amygdala when you are sleep deprived?

Answer 18

It is over active, when you are asleep the amygdala is connected to the medial PFC which acts as brakes on the amygdala (controlling it)
When you are sleep deprived, there seems to be a disconnect between these 2 regions, so no longer have control and explains the increased activity

Question 19

How can sleep affect weight management?

Answer 19

Can help with appetite control when get sufficient sleep
Even PSD can affect weight management
2 key hormones involved in regulating metabolism:
- leptin
- ghrelin

When you are sleep deprived there is a disruption in these hormones

Question 20

What is Ghrelin?

Answer 20

a fast acting hormone produced in the cells of the stomach and increases the drive to eat
When you are sleep deprived there is an increase in ghrelin levels so an increased drive for high calorie food

Question 21

What is Leptin?

Answer 21

Produced in white fat cells and suppresses the appetite, it tells us when we’re full
When you are sleep deprived there is a decrease in leptin so are reduced feelings of satiety

Question 22

What is the combined effect of these 2 hormones?

Answer 22

Collectively increase appetite and increase food consumption
Linked to obesity
Sleep deprived bodies will hold onto all the fat and are more likely to lose muscle

Question 23

What is the effect of SD on the immune system?

Answer 23

It is the same as putting your body under stress
It weakens the immune systems by reducing NK cell levels which are key for fighting off infections
If people are chronically sleep deprived then they will have chronically reduced NK cell levels

Question 24

What are the effects of SD on neurodegeneration?

Answer 24

Beta-amyloid plaques are linked to Alzheimer’s disease.
Studies have found that poor sleep leads to a beta-amyloid build up.
Deep sleep usually clears toxins but without it they will present
This build up will eventually lead to neuronal death and synapse loss which is linked to Alzheimer’s and cognitive decline

Question 25

What is tipsy driving like vs. tired driving?

Answer 25

Micro-sleeps are observed in sleep deprived drivers, they are asleep but still manage to operate the vehicle (automatic behaviour)
Performance on a driving simulator task showed that the sleep deprived PP was worse at driving than the drunk PP
This has implications for road use, more likely to crash due to lack of response

Question 26

What are some methodological limitations of sleep deprivation studies?

Answer 26

Don’t take naps into account - can impact conclusions
There are practice effects in certain tasks
There is divergence between subjective and objective measures
The differences in paradigms make it difficult to make comparisons, especially for PSD
Individual differences

Question 27

Can we overcome SD?

Answer 27

People may turn to caffeine/sugar to boost energy
Take naps
Lie in on the weekend
We should value sleep on a daily basis so we don’t have to make up for it

Question 28

What can periods of extended wakefulness do?

Answer 28

Neurons may begin to malfunction, visibly affecting a person’s behaviour and performance
It also increases migraines and epileptic attacks

Question 29

What happens to adenosine in SD?

Answer 29

Increased levels which promotes sleepiness and has general inhibitory effect on neural activity

Question 30

What was first believed about serotonin in relation to SD?

Answer 30

That it was the neuro-modulator of sleep due to the destruction of 5-HT neurons/inhibition of 5-HT synthesis inducing severe insomnia

Question 31

What can be seen in sleep duration in the general population?

Answer 31

There is a reduction in sleep length
Among college students, a 30 min decrease in self-reported sleep duration was found 1978-1988
This was ascribed to possible uncontrolled changes in work load

Question 32

What is important for optimal efficiency during wakefulness?

Answer 32

It may sometimes depend more upon the maintenance of a regular sleep-wake rhythm than on obtaining a normal amount of sleep e.g. going to bed at the right time rather than getting 8 hours sleep at 4 a.m

Question 33

Whats an example of support for Van Dongen et al. (2003)?

Answer 33

Dinges et al.
Performance deteriorated more, with more sleep restriction
Deteriorated most rapidly in 4 hour condition

Question 34

Whats a problem with sleep extension studies?

Answer 34

The ability to sleep for >10 hours is a distinctive feature of only some individuals
May be difficult to carry out