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