14.3 - Effects of Sleep Deprivation

Question 1

Why is t difficult to measure the effects of sleep deprevation in an effective manner? (2 reasons for this, and implications)

Answer 1

STRESS

1. most people who sleep little do so bc of stress, which has independent effects
2. sleep deprivation procedures are often stressful - makes experiments troublesome
3. so, we need to examine the effects of sleep deprivation carefully

Question 2

What are the three predictions of recuperation theories n terms of sleep deprivation

Answer 2

1. long periods of wakefulness will produce physiological and behavioural disturbances
2. disturbances grow in proportion to sleep deprivation
3. after long deprivation periods end, much of the missed sleep with be regained

Question 3

Explain the Kleitman 1963 study on sleep deprived students

Answer 3

total sleep deprivation - similar effects between participants

1. first night - read to studied with no problems until 3 AM, then got very sleepy, had to be kept awake
2. next day, alert as long as they were active - second night couldn’t read or study, sleepiness was so severe, after 3 AM sleepiness was overpowering
3. third morning, decrease in sleepiness, students could perform tasks as long as they were standing and moving
4. third and fourth days were the same as the other nights, but sleepiness got more severe
   - things did NOT GROW WORSE after the forth night, those who persisted went through the same cycle

Question 4

Explain the case of Randy Gardner

Answer 4

tried to break the WR for longest hours of consecutive wakefulness

• researcher Dement joined the team
• Randy complained when his team mates didn’t let him close his eyes
• but his behaviour was not disturbed
• held a press conferences the last night (264 hours)
• conducted himself well
• slept only 14 hours the first night, then returned to his 8 hour schedule, which is typical

Question 5

what have experimental studies of sleep deprivation in humans measured?

Answer 5

sleepiness, mood, cognition, motor performance, physiological function, molecular function

Question 6

what are the three consistent effects of moderate sleep deprivation (3-4 hours less than normal sleep)?

Answer 6

1. increase in sleepiness
2. negative affect
3. perform poorly on tests of sustained attention

Question 7

what are the effects of sleep deprivation on complex cognitive functions?

Answer 7

inconsistent, so we study on simple, dull and monotonous tasks that are most sensitive to sleep dep.
- only some cognitive functions are susceptible

Question 8

what are the cognitive functions that are immune to sleep deprivation?

Answer 8

logical deduction, critical thinking

Question 9

what cognitive functions are disrupted by sleep deprivation?

Answer 9

executive function, which are dependent on the pfc
- includes. innovative, lateral and insightful thinking, as well as assimilating new information to update plans and strategies

Question 10

what have many researchers claimed needs further investigation in the study of cognitive effects of sleep loss?

Answer 10

the degree to which deficits in. vigilance and motivation produced by sleep loss can be mistaken for cognitive deficits

Question 11

what are the effects of sleep deprivation on physical performance?

Answer 11

inconsistent results, only a few measures are affected even after long periods of deprivation

Question 12

what are the effects of sleep deprivation on physiology?

Answer 12

1. reduced body tempt
2. increased blood pressure
3. decreases in aspects of immune function
4. hormonal changes
5. metabolic changes

Question 13

what is the problem with interpreting the effects of sleep deprivation on physiology
- what study skirted this problem

Answer 13

little evidence they have any consequences on performance

• ex, decline n immune function has been discovered in sleep deprived volunteers, doesn’t really mean they would be more susceptible to infection, immune system is extremely complicated and a decline n one aspect is often compensated for by other changes
• Prather and colleagues (2015) - studied susceptibility to infection and illness directly

Question 14

describe the Prather and colleagues (2015) study on illness and infection susceptibility and sleep deprivation

Answer 14

exposed 164 healthy volunteers to a cold virus, those who slept less than 6hrs/night were not more likely to get infected, but were more likely to get sick
- only correlation, can’t be proven certain yet

Question 15

what are micro sleeps? when do they happen?

Answer 15

brief, 2-3 second sleeps during which eyelids droop and volunteers become less responsive to external stimuli even tho they remain sitting or standing
- after 2-3 days of continuous deprivation

Question 16

what do micro sleeps disrupt? is tis only disrupted by micro sleeps?

Answer 16

vigilance, no, sleep deprived ppl wo micro sleeps also experience decreases in vigilance

Question 17

why are the effects of sleep deprivation studies so odd?

Answer 17

1. compared with other motivated behaviours (sex, hunger), sleep deprivation effects are minor and subtle
2. performance deficits observed even after 64 hours of deprivation are eliminated in 4 hours

Question 18

what is the caruosel apparatus

Answer 18

yoked control paradigm - when EEG activation says the experimental rat is sleeping, the disk which is the floor for both chambers rotates

• if the experimental rat does awake immediately it gets tossed into water
• the control is the same, but if it wakes it can avoid getting dunked by walking in the opposite direction of the disk
• experimental rats die in 12 days, yoked controls stay healthy

Question 19

why are the findings of the carousel apparatus difficult to interpret?

Answer 19

the fact that sleep deprivation studies in humans haven’t really shown the same results - maybe repeatedly awakening the rats kills them bc it is stressful

Question 20

what supports the ‘stress’ interpretation of the carousel apparatus findings?

Answer 20

• interpretation is consistent with the pathological problems observed in the experimental rats post mortem - swollen adrenal glands, gastric ulcers and internal bleeding

Question 21

why might sleep deprivation be impossible to productively studied in humans

Answer 21

the unavoidable confounding effects of extreme stress

Question 22

what are the two effects of rem sleep deprivation

Answer 22

1. following deprivation, participants display REM rebound - more than usual amount of rem for the first 2 or 3 nights
2. each successive night of deprivation, there is a greater tendency for participants to initiate REM - participants have to be awakened more and more often as the study goes on to keep them from getting the rem sleep

Question 23

what is an example of the increased tendency to enter REM if we are deprived of it?

Answer 23

first night, participants had to be awakened 17 times to stop rem, but during the 7th, 67

Question 24

what does the compensatory increase in REM following REM deprivation suggest (2)

Answer 24

1. REM is regulated separately from slow wave sleep

2. REM serves a special function

Question 25

what is an area of considerable interest in the effects of sleep - list the postulates
- are the results convincing?

Answer 25

memory

1. REM strengthens explicit memories
2. slow-wave sleep promotes consolidation
3. memories of daily experience are processed prior to consolidation during sleep
   - NOPE, no strong association between sleep and memory

Question 26

why does the sleep of depressed patients present a challenge to the idea that sleep influences memory?

Answer 26

depressed patients get less slow wave sleep, but no memory disturbances
- antidepressants eliminate REM - again no memory disturbances

Question 27

what is the default theory of REM sleep

Answer 27

difficult to stay in NREM all the time, so the brain periodically switches to either REM (if there are not biological requirements at the time) or awake (if there are)

Question 28

what does the default theory of REM sleep posit in terms of the function of REM

Answer 28

prepare organisms for wakefulness in natural environments where immediate effective activity is necessary

Question 29

explain the Nykamp and colleagues (1998) study that supports the default theory of REM sleep

Answer 29

awakened ppl every time they entered REM, but subbed a 15 minute period of wakefulness for each lost REM period, under these conditions, they were not tired despite getting only 5 hours of sleep, displayed no rem rebound.

• seemed to be no need for REM if periods of wakefulness were substituted
• replicated in rats
• consistent with the increase in nighttime awakenings in those on antidepressants and REM is abolished

Question 30

what is one of the positive effects of sleep deprivation

Answer 30

individuals deprived of sleep become more efficient

- sleep has a higher proportion fo slow wave sleep (NREM 3) which seems to serve the main restorative function

Question 31

what are the 6 pieces fo evidence that support the idea that sleep deprivation increases sleep efficiency

Answer 31

1. ppl regain most of their slow wave, but not most of their other forms of sleep, after deprivation
2. after deprivation, slow wave sleep is characterized by even more slow waves than usual
3. ppl who sleep 6 hours or less per night have a higher proportion of slow waves than those sleeping 8
4. reducing sleep time gets less NREM1 and 2, but slow wave duration doesn’t really change
5. taking a nap in the morning after a full nights sleep I- few slow wave periods, doest reduce duration of the following nights sleep
6. repeatedly waking ppl during REM produces little increases in sleepiness the next day, while waking individuals during slow wave has major effects

Question 32

what does the fac that sleep becomes more efficient in people who sleep less result in/

Answer 32

the fact that conventional sleep deprivation studies are pretty much useless for discovering how much sleep ppl need. Our bodies def response poorly to getting less sleep than normal, but the negative consequences of sleep loss in inefficient sleeps does not indicate whether the lost sleep was actually needed

Question 33

what is the only way to assess the tru needful sleep?

Answer 33

experiments where sleep is regularly reduced for many weeks to get the participants to adapt to getting less sleep by increases efficiency. Only once ppl are sleeping at maximum efficiency can we gauge how much they need