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unu bst > somnul > Flashcards

somnul Flashcards

1
Q

how much do we sleep

A

we spend 33% sleeping

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2
Q

what is sleep

A

state of immobility
responsiveness to world decreases
reversible - we can be woken up

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3
Q

what is sleep

A

a state in which there is a shift in consciousness
We exhibit changes in various physiological processes: including brain activity, consciousness

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4
Q

what are the 2 distinct classes of sleep

A

NREM
REM - small amplitude, fast, high, frequency EEG waves, rapid eye movements

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5
Q

what are the brain activities during relaxed, wakefulness sleep

A

alpha waves
of high frequency
waves present when one begins a state of relaxation

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6
Q

what are the brain activities during stage N1

A

Lightest stage of sleep
If someone wakes you up you might have not even realised you were asleep
irRegular, low amplitude
Brain activity begins to decline and there is decrease in frequency

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7
Q

what are the brain activities during stage N2

A

deeper than N1
sleep spindles and k-complexes
k-complexes are the largest event that are seen

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8
Q

what are the brain activities during N3

A

deepest stages of sleep
characterised by low frequency, high amplitude waves
delta waves

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9
Q

what are the brain activities during REM sleep

A

irregular
low amplitude
high frequency waves
these reflect brain activity when we are awake

loss of muscle tone
more likely to dream vivid dreams

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10
Q

what happens when we fall asleep

A

go through stages N1, N2 and N3
after an hour person begins to cycle back through the stages from N3 to N2 and then REM

sequence repeats every 90 mins

N3 decreases as the night progresses
length of REM increases as the night goes on

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11
Q

2 process model describe 2 drives for sleep

A

homestatic
circadian

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12
Q

homeostatic

A

the longer we’ve been awake, the greater out drive for sleep

substances building up the longer we are awake

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13
Q

sleep homeostatis

A

longer youve been awake, the greater our sleep drive

when we are sleep deprived:
- sleep duration increases
- sleep intentisty increases

more difficult to wake someone from deep sleep N3 - when slow waves are present

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14
Q

what is process s

A

when we are awake certain substances accumulate in the cerebrospinal fluid which can induce sleep

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15
Q

adenosine

A

regulates NREM sleep
adenosine is a by-product of energy metabolism

with increased metabolism, neural activity and wakefulness extracellular adenosine builds up in the brain

presence of adenosine slows rate at which neurones fire - sleepiness

caffeine is an adenosine blocker - increase in time spent awake

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16
Q

what is circadian process

A

circadian rhythm - biological process that displays an endogenous, entrainable oscillation of about 24h

circadian - about a day
endogenous - something from within
entrainable - we can use environmental cues to adjust our rhythms to the world around us

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17
Q

entrain our rhythm

A

we use zeitgeber - time giver
external cues that can control the timing of circadian rhythms

zeitgebers can be manipulated to increase of reduce length of circadian rhythms

light, excercise

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18
Q

individual differences in circadian rhythms

A

circadian phase exhibits wide inter-individual variation

individual phase called chronotype

some ppl like functioning in the morning

-evening types have a phase delayed circadian rhythm
-morning types have a phase advanced circadian rhythm

chronotype influenced by genes

19
Q

what is the evolutionary advantage of different chronotypes

A

help early social individual humans be active and alert at different times of day to enhance survival

20
Q

why do we have a biological clock

A

allows animals to be active during the times that are most adaptive for them - humans in the day time

allows us to function on same schedule and function as a society

21
Q

what is evidence for biological clock

A

if someone lived without external cues to know what time of day it is

free running pattern
can still demonstrate regular sleep wake cycle

22
Q

suprachiasmatic nuceli

A

master clock
coordinates clocks throughout the body
clock genes are important in generating these cycles
genes interact producing an auto regulatory feedback loop

23
Q

SCN

A

tiny region in anterior hypothalamus
superior to the optic chiasm - where optic nerves cross

24
Q
A

scn controls the pineal gland
- important for production of melatonin
melatonin is the darkness hormone - tells body what it should be doing when ti gets dark - falling asleep

in animals melatonin tells them to be active

when there is less light, the SCN tells brain to make more melatonin which can make you feel drowsy

melatonin is inhibited by light

25
Q
A

melatonin has circadian rhythm
increases as evening sets in
peaks in middle of night
then decreases
lowest level just before we wake up

26
Q
A

SCN synchronises local clocks in organs and tissues throughout the body, either through hormones or changes in body temperature

there are some gene operated clocks that are independent of the brains master pacemaker - liver, lung, testis

27
Q
A

specific lesions of SCN disrupt various circadian cycles including sleep-wake cycles

this does not affect sleep length, but affects periods or cycles of sleep

28
Q

bilaterial lesions

A

bilateral lesions of SCN have abolished some circadian rhythsm but not others

other brain regions could be involved

SCN lesions block entrainment to light but not to other factors like food

29
Q

other areas involved in sleep

A

VLPO becomes more active when we fall asleep
inhibits brain areas involved in arousal ARAS

30
Q
A

objective measures
subjective measures

31
Q

polysomnography

A

electrical brain potentials can be used to classify levels of arousal and stages of sleep

includes EEG EOG AND EMG

EEG - recording electrical activity from brain by placing electrodes on the scalp

EOG - electrodes placed on outer canthus of the eyes. can record eye movement

EMG - recording muscle activity. electrodes can be placed on the chin or legs - provides info about REM sleep

32
Q

PSG

A

stages of sleep
sleep stages transitions
microstructure (sleep spindles / K complexes) - found during N2

33
Q
A

sleep onset latency - time it takes to fall asleep
total sleep time
sleep efficiency - time spent in bed that youre alseep
wake after sleep onset
number of awakenings

abnormalities during sleep
muscle activity: restless leg
respiratory: apnoeas (pauses in breathing during sleep), hypopneas (reduction in breathing)

34
Q

drawbacks

A

expensive
time consuming

difficult to get data collected over long periods
people dont want to spend extensive periods in sleep labs

participants sleep worse during the first night
sometimes opposite effect is observed - they sleep better in a sleep lab

35
Q

first night effect

A

1st and 2nd night spent in lab
during 1st night, part of left hemisphere stayed alert during sleep
left hemisphere fell into a lighter sleep compared to right
left remained responsive to sounds in environment
ensuring safety

36
Q

drawbacks

A

subjective sense of poor sleep

children with depression report struggling to sleep at night
but in sleep lab there is less strong evidence for this

paradoxical insomnia - someone may report symptoms of insomnia but these are not verified by sleep lab

37
Q

actigraphy

A

wrist watch like device
non invasive
assesses movement during sleep

doesnt tell us about sleep stages but tells us about sleep onset latency, total sleep time, time in bed, number of wakings

38
Q
A

useful for assessing circadian rhythm, free running period, circadian rhythm disorders, excessive daytime sleepiness, and periodic limb movement

39
Q

pros

A

non disruptive
used at home

cons
issues with accuracy
cant distinguish between rest and sleep
can overestimate sleep

40
Q

orthosomnia

A

ppl are becoming obsessed with perfect sleep
preoccupation with maintaining perfect sleep
there is no perfect sleep

41
Q

questionnaires

A

sleep quality index

insomnia severity index

preference in chronotype

42
Q

pros of self report

A

easy to administer
can recruit large samples
for insomnia self report is key

43
Q

cons of self report

A

reporter bias
discrepency between subjective and objective data
people may not be aware of sleep apnoea

44
Q

measuring circadian phase markers

A

body temperature
melatonin
measure this to tell us about circadian phase

unu bst (18 decks)

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