sleep Flashcards
identify three ways of measuring sleep
1/ electro-encephalogram (EEG) - head
2/ electro-oculogram (EOC) - eye
3/ electro-myogram (EMG) - neck
outline the stages of sleep
pre-sleep
stage 1
stage 2
stage 3
stage 4
describe the electrical activity that occurs in pre-sleep
- alpha waves
- bursts of 8-12Hz of activity
- low amplitude
- high frequency
describe what happens in stage 1 of sleep
- amplitude starts to increase
- frequency starts slowing down
describe what happens in stage 2 of sleep
- sleep spindles
1-2 second quick bursts of 12-14Hz waves - K complex
sharp up and down deflection
describe what happens in stage 3 of sleep
- frequencies progressively slower
describe what happens in stage 4 of sleep
- very large amplitudes
how long does a sleep cycle last?
90 minutes
(from stage 1 - 4)
what is the first stage 1 called?
initial stage one
what are the subsequent stage 1’s called?
emergent stage 1
what is REM?
rapid eye movement
outline Dement (1978) findings into the stages of sleep
- found 80% of those that woke up during REM sleep can recall their dream
- found 93% of those that woke up during nREM = no dream recall
- nREM (slow wave sleep) could only recall isolated experiences of the dream
- REM dream could recall the narrative of the dream
identify 2 theories of sleep
1/ recuperation theories
2/ evolutionary theories
explain what recuperation theories of sleep are
- idea that being awake disrupts homeostasis
- when you sleep, homeostasis is restored
- e.g.: sleep restores energy levels
explain what evolutionary theories of sleep are
- idea that sleep has evolved in humans to prevent accidents and predation at night
- suggests that sleep is not needed but we are motivated to have it
does sleep depend on species size?
- no
- sleep is not related to body size/temperature
- it has been found that exercise has little/no effect on sleep duration in humans
(Youngstedt & Kline, 2006)
what theory of sleep is sleep in animals consistent with?
- not consistent with recuperation theory
- related to evolutionary theory
sleep in animals depends on two factors:
- how vulnerable you are asleep
- time spent eating during the day
how is sleep deprivation explained by recuperation theory?
- recuperation theory suggests that sleep deprivation increases physiological/behavioural disturbances
- after deprivation, theory suggests missed sleep must be regained
what did Cirelli (2006) find about sleep deprivation?
- found sleep deprivation influences mood, physiological function, molecular function
- consistent with recuperation theory as it demonstrates physiological/behavioural disturbances brought on by sleep deprivation
outline findings from Dement (1978) that counters the recuperation theory
- Randy Gardner kept awake for 260 hours
- after 14 hours sleep = back to normal
explain the effects of sleep deprivation in humans (with links to depression) (Vogel et al., 1975, 1990)
- found that depressed people go into REM sleep very easily but it is very disturbed
- preventing REM in depressed patients acts a an antidepressant
- if you suppress REM sleep, people want it more
- suppressing REM sleep and making body want it more regulates the irregular pattern of sleep that is seen in depressed people
describe the effects of sleep deprivation in animals
- after several days of sleep deprivation, animal died
- post-mortem showed swollen adrenal glands, gastric ulcers, internal bleeding
what brain areas are involved in sleep?
- hypothalamus
- reticular system
explain the role of the hypothalamus in sleep
- those who had difficulty sleeping had damage to anterior hypothalamus
- those who had difficulty staying awake had damage to posterior region of hypothalamus
explain the role of the reticular system in sleep
- reticular system = near the brainstem
- Cerveau isole transection = showed slow-wave sleep pattern
- Encephale isole transection = showed Normal sleep-wake cycle
suggests that wakefulness area = somewhere between the two
- found that stimulation of reticular system in sleeping cats, woke cats up
what is narcolepsy?
sudden urge to fall asleep during wakefulness
what is core muscle atonia?
where muscles are fully relaxed
