sleep

Question 1

how many hours of sleep will a human get in a lifetime on average?

Answer 1

around 175,000 hours

Question 2

what are the three principles of sleep?

Answer 2

electro-encephalogram (EEG) - head

electro-oculogram (EOC) - eye

electro-myogram (EMG) - neck, measure muscle tone

Question 3

what are the problems with a sleep laboratory?

Answer 3

expensive

gaining data is difficult

time-consuming

people don’t sleep well in strange situations/new contexts

Question 4

what happens as we fall asleep?

Answer 4

rapidly move into stage 1 sleep then progress into stage 2 (where we spend most of the night)

Question 5

what are pre-sleep alpha waves?

Answer 5

bursts of 8-12 Hz activity in low amplitude/high frequency waves

Question 6

how many stages of sleep are there?

Answer 6

four

Question 7

what is progressive sleep?

Answer 7

increase in amplitude

decrease in frequency

Question 8

what is a sleep spindle?

Answer 8

1-2 second burst of 12-14 Hz waves

Question 9

what is a K-complex?

Answer 9

single large upward then downwards deflection

largest even in human health EEG

Question 10

what is it suggested that K-complex and sleep spindles are involved in?

Answer 10

memory consolidation

Question 11

what happens during the night?

Answer 11

cycle through stages of sleep

as night progresses, spend more time in stage 1

also periods when people are entirely awake but these are not recaleld

Question 12

how long is a sleep cycle on average?

Answer 12

90 minutes

Question 13

when does REM start?

Answer 13

after initial stage 1 (in emergent stage 1)

Question 14

what is REM sleep?

Answer 14

correlated with dreaming?

early studies of REM sleep indicated high rates of blood flow, oxygen consumption and neural firing

increase in variability of the ANS (blood pressure, pulse, respiration)

REM sleep episode seemed emotional charged

Question 15

what did Dement (1978) find about REM sleep?

Answer 15

80% awakenings during REM sleep = dream recall

93% awakenings during nREM sleep = no dream recall

nREM dream recall = isolated experiences (e.g. perception of falling)

REM dream recall = more narrative

Question 16

what did Dement and Kleitman (1975) find about REM sleep?

Answer 16

participants awoken 5-15 minutes after onset of REM

asked on basis of dream events, how long they had been dreaming (5-15 minutes)

participants correct 91/111 cases

Question 17

what are recuperation theories of sleep?

Answer 17

being awake disrupts homeostasis

sleep restores this

e.g. sleep restores energy levels

Question 18

what are evolutionary theories of sleep?

Answer 18

sleep is not a reaction to homeostasis disruption

sleep evolved (in humans) to prevent accidents and predation at night

sleep is like sex - don’t need to stay alive but still motivation to have it

Question 19

what is sleep in animals like?

Answer 19

all mammals and birds sleep

fish, reptiles and amphibians have periods of inactivity too

large species difference in sleep - not related to body size/temperature

sloths hardly move yet need 20 hours/day

little/no effect of exercise on sleep duration in humans (Youngstedt and Kline, 2006)

Question 20

is sleep in animals consistent with recuperation theories?

Answer 20

no

Question 21

what do evolutionary theories say sleep is related to?

Answer 21

how vulnerable you are asleep

time spent eating/day

Question 22

what do recuperation theories predict will happen with sleep deprivation and are they true?

Answer 22

increases in physiological/behavioural disturbances - yes

after deprivation, missed sleep must be regained - no

Question 23

what did Cirelli (2006) say about sleep deprivation?

Answer 23

influences mood, physiological function, molecular function

Question 24

what are the effects of sleep deprivation on executive function?

Answer 24

Curcio et al (2006)

assimilating changing information

updating plans

references memory

Question 25

what did Dement (1978) find about how well people recover after sleep deprivation?

Answer 25

Randy Gardner 260 hours awake 1st recovery night = 14 hours sleep then back to normal

Question 26

what did Vogel et al (1975, 1990) find about depression and sleep deprivation?

Answer 26

preventing REM sleep acts as an antidepressant

Question 27

what did Scherschlicht et al (1982) find about depression and sleep deprivation?

Answer 27

examined effects of 20 antidepressants all reduced REM sleep most increased slow-wave sleep

Question 28

what has been found about depression and sleep?

Answer 28

preventing REM sleep makes the body want it more (Webb and Agnew, 1967) deprivation of REM sleep causes a transient rebound (Brunner et al, 1990) few cognitive or emotional effects however

Question 29

what is REM sleep for?

Answer 29

default (i.e. hard to stay in nREM sleep) more similar to wakefulness (people not tired after REM sleep deprivation)

Question 30

what was the study that investigated sleep deprivation in rats?

Answer 30

two rats on turn table going through two separate chambers both rats have EEG measured when experimental rat sleeps, table turns and dunked in water after several days, experimental rats died but post-mortem revealed swollen adrenal glands, gastric ulcers and internal bleeding possibly a consequence of stress and physical damage

Question 31

what brain areas are involved in sleep?

Answer 31

hypothalamus reticular system

Question 32

how is the hypothalamus involved in sleep?

Answer 32

Contantin von Economo studied the brains of those who died from the virus encephalitis lethargica victims who had difficulty sleeping - damage to anterior region victims who had difficulty staying awake - damage to posterior region

Question 33

how is the reticular system involved in sleep?

Answer 33

complex network of brainstem nuclei and neurons area became known as the reticular activating system (low activity = sleep, high activity = wakefulness)

Question 34

what did Bremer (1936) find about the involvement of the reticular system in sleep?

Answer 34

cerveau isole transection = slow-waves sleep pattern encephale isole transection = normal sleep-wake cycle "wakefulness" area = somewhere in between the two

Question 35

what did Mouzzi and Morgan (1949) find about the involvement of the reticular system in sleep?

Answer 35

stimulation of the reticular formation of sleeping cats woke them

Question 36

what are sleep disorders?

Answer 36

narcolepsy REM sleep without core muscle atonia

Question 37

what is narcolepsy?

Answer 37

rare long-term brain condition that can prevent a person from choosing when to wake or sleep brain unable to regulate sleeping and waking patterns normally excessive daytime sleepiness - feeling very drowsy throughout the day and finding it difficult to concentrate and stay awake sleep attacks - falling asleep suddenly and without warning cataplexy - temporary loss of muscle control resulting in weakness and possible collapse, often in response to emotions such as laughter and anger