somnul 2

Question 1

what do we mean by enough sleep

Answer 1

there are individual differences when it comes to sleep requirements

newborn babies need 14-17h sleep

recommended amount of sleep decreases through the life course

adults: 7-9h

Question 2

what are the individual differences

Answer 2

some people can function on less sleep than hours

when people sleep very long or very short, could be a sign of health problems

you may be sleep deprived, if you can’t wake up when alarm goes off, and know that you are not functioning to the best of your ability

Question 3

major effects of total sleep deprivation

Answer 3

scientists looked at effects of total sleep deprivation in rats
rats were put on a rotating disk
if they stopped moving, they would be pushed and thrown in to water

there was wight loss
skin became problematic
problems with regulating temperature
in 2-3w they died

Question 4

fatal familial insomnia FFI

Answer 4

a rare genetic disease

ppl miss out on sleep and die within an average of 18m

abnormal proteins build up in the brain

attacks the thalamus which is important in sleep-wale cycles

results in reduction in sleep length and deterioration of sleep stages

Question 5

does the sleeplessness lead to death in FFI

Answer 5

symptoms of FFI include dementia, problems speaking and swallowing

it’s not insomnia that is leading to death - not clear

Question 6

sleep deprivation in humans

Answer 6

1964

17yo agreed to stay awake for 11 days
beat the world record

no caffeine available

he showed marked circadian rhythms in sleepiness

occasional hallucinations

showed ataxia (inability to perform coordinated movements)

increased irritability

speech difficulties

deficits in attention and memory

reduction in body temperature

Question 7

can you catch up on missed sleep

Answer 7

Randy was allowed to sleep again

on first night he slept for 15 hours

by the end of the week he was getting 9 hours

a week after experiment he was getting 7h

Question 8

what happened when randy fell asleep after the experiment

Answer 8

his body prioritised REM sleep and deep NREM sleep

there was less light sleep

so this tells us these types of sleep are important

Question 9

effect of sleeplessness in crashes

Answer 9

multiple crashes due to sleep deprivation

more than 20% of fatal crashes involve a driver who was drowsy

Question 10

sleep deprivation impairing performance

Answer 10

ppts sleep deprived for 28 hours

another group was given alcohol steadily

hand-eye coordination was assessed repeatedly

RESULTS
decrease in performance as a result of being awake for 24 hours was equivalent to having a blood alcohol concentration above the drink drive limit

Question 11

the way we sleep is linked to health

Answer 11

the way u sleep is linked to
ADHD
ASD
anxiety
depression
PTSD
conduct disorder

Question 12

effect on short sleep on immune system

Answer 12

short sleep compromises the immune system

sleep assessed for a week in ppts

ppts were given nasal drops - virus that causes common cold

those who got up to 6h sleep were more likely to get a cold than those who slept for longer periods

BUT
when sleep length was reported by self report, these associations weren’t found - results from studies may depend on whether we use objective or subjective measures

possibility: ppl aren’t good at estimating their own sleep length

Question 13

cost of not getting enough sleep

Answer 13

cost of insufficient sleep on the economy

decrease in potential in adolescence
decrease in performance
absenteeism

insufficient sleep costs the UK £40 billion each year

Question 14

theories of sleep

Answer 14

evolutionary theory
restorative theory
information/memory processing

Question 15

evolutionary theory

Answer 15

during sleep we become less aroused

we become vulnerable to predators

lack movement - cannot escape quickly

Question 16

sleep as a way to conserve energy

Answer 16

sleep might have evolved to conserve energy

sleep conserves energy during times of inefficiency

body temp decreases during sleep

muscular tension, blood pressure and rate of respiration is reduced

when we are REM sleep deprived there may be excessive heat loss

when we are NREM deprived we need to use excessive energy in oder to maintain temperature

Question 17

what are some exceptions

Answer 17

REM sleep doesn’t save any energy compared to being awake

dolphins
- one hemisphere goes into deep sleep
- the other stays awake
- they can keep swimming so they are not conserving much energy

Question 18

update of evolution of sleep

Answer 18

different behavioural states allow for energy to be allocated optimally to vital biological processes

when awake we can use energy for reproduction

when we sleep we use energy for neural network reorganisation and growth

Question 19

restorative theory

Answer 19

when we are asleep we restore our brain and body

when we sleep our metabolic requirements are replenished

growth hormone is released to the greatest extent during our deep sleep - allows for cell reproduction

sleep allows us to restore hormone and neurotransmitter levels

sleep allows growth of synaptic connections

Question 20

against restorative thoery

Answer 20

protein synthesis occurs 24h a day, not just during N3 altough it seems to peak in N3

amount of sleep does not appear to decrease when our level of daytime activity decreases

theory predicts that more active species will sleep longer. however, 1 of the least active creatures, the sloth, sleeps for about 20h per day

Question 21

metabolic homeostasis

Answer 21

metabolic - the chemical reactions in our cells

homeostasis - balance, maintaining equilibrium

Question 22

the role of sleep in clearing metabolites from brain

Answer 22

sleep in mice
during sleep, there was a 60% increase in interstitial space, resulting in an increase in the exchange of cerebrospinal fluid with interstitial fluid

this allowed the clearance of beta amyloid from the brain

toxins build up in the brain when we are awake - beta amyloid - an amino acid centrally involved in Alzheimer’s

when we sleep certain brain cells (glial cells) shrink and this allows more space for fluid to remove toxins from brain

Answer 23

scientists who imaged the brain of mice, showed that the glymphatic system became 10x more active when them mice were asleep

Question 24

sleep in supporting immune system

Answer 24

defence against pathogens is mediated by central nervous system and changes to concentrations of immune signalling molecules called cytokines

concentrations of cytokines naturally vary with sleep wake cycles

cytokines can cause immune system to increase t cells to help fight infections

Question 25

information and memory processing theory

Answer 25

sleep may have evolved for learning and memory consolidation

the ability to learn and memorise info is metabolically expensive

during sleep, the info coming through sensory systems is minimal - metabolic demands associated with this are low

-during this inactive phase, new brain circuits are laid down

Question 26

how is memory consolidated during the mind

Answer 26

during sleep, newly formed memory representations are reactivated

this reactivation aids in the redistribution of memories from STM in a part of the brain called the hippocampus into LTM in areas of the cortex

this reactivation process occurs during NREM sleep

REM sleep is thought to stabilise reactivated memories to ensure they remain in LTM, integrated with other relevant memories

Question 27

studies supporting info memory theory

Answer 27

young adults reporting poor sleep quality also performed less well on attention tasks

ppts 16-19 who get less sleep and whose schedules differs most at the weekend compared to the week get a lower grade point average

difference in terms of schedule from weekdays to weekends is called a social jet lag - operating on a different schedule on our days off

Question 28

sleep important for insight

Answer 28

mendeleyev

he was struggling with some of the rules in order to develop the table and the key rule came to him in a dream

Question 29

support for sleep resulting in insight

Answer 29

3 groups
each had 3 training blocks and 10 final blocks

the difference was the period in between their training and final block

they were either asleep from 11pm-7am

awake from 11pm-7am

or awake in the day from 11am-7pm

in the training block ppts had to analyse and 8 digit string of 1s, 4s and 9s from left to right

task was to work out the rules: can u see what the rules are

if digits are the same, the response should be the same digit

if digits were different the response should be the remaining digit

RESULTS
20% of those who were awake during the day and awake during night got answer correct
60% got correct response when sleeping

Question 30

can brain respond to stimuli when asleep

Answer 30

our brain can respond to auditory stimuli when we are asleep

k complexes are present during N2 sleep

ppts asked to remember target names whilst they were awake

then when they were asleep names were played to them, including their own name and other controls

k complexes appeared in N2 when names were played

k complexes responses to target names were larger and more reliable than control names

largest k complexes to their own name

Question 31

can we learn when we are asleep

Answer 31

new born babies were played tunes

when tunes were played, experimenter gave air puff to baby - air blown gently into their eyes

upon hearing the tune they learnt to scrunch up their eyes

unlikely more complex infor can be learnt this way

attempts to learn new info while asleep - focusing on other age groups have failed