3 - Human Sleep Flashcards
Mostly talking about undergraduates, which comes with some caveats. - Young Adult - Diurnal (not working night shifts) - Relatively healthy
From what stage do you enter REM sleep?
Stage 2
The stage you spend most of the night in and that you transition through to other stages
How long does the first stretch of low wave sleep last?
60-90 minutes
What is the hypnogogic period?
A period in stage 1 sleep where there might be vivid hallucinations while falling asleep (hypnagogic hallucinations)
What is the hypnopompic period?
The period right after waking
What is the REM/nREM cycle?
The cycles of nREM followed by REM throughout sleep
Does REM or nREM sleep dominate a night of sleep?
nREM
Rank the stages of sleep from most in a night to least
- nREM (mostly stage 2 sleep)
- REM
- WASO (wake after sleep onset) (least, about 5%)
What does the amount of slow wave sleep depend on?
How long you’ve been awake, how much sleep debt you have.
What does the amount of REM sleep you get depend on?
The circadian clock (eg. what time of day the body thinks it is)
The probability of having slow wave sleep increases/decreases throughout the night?
Decreases
The probability of REM sleep increases/decreases throughout the night?
Increases
When are you probable to fall into REM sleep?
The late morning to the early afternoon,
Virtually no chance early in the evening
This is controlled by the circadian clock
What happens to the probability of having REM or slow wave sleep when you are sleep deprived?
REM sleep: Chance decreased from normal levels and decreases even though they’ve been away for longer (doesn’t change a huge amount as it’s modulated by circadian clock)
Slow wave sleep: Chance increases highly and increases further as sleep deprivation continues
Slow wave sleep overtakes the probability of REM sleep during the day after a certain level of sleep deprivation
Forced internal synchronization experiments show what about REM sleep during sleep deprivation?
That REM is closely linked to circadian rhythms
Some behaviours do seem to have a cyclic period to them, eg. eating, chewing, smoking (oral behaviours) that seem to oscillate in a roughly 90 minute basis. What does this maybe suggest?
Suggests that REM/nREM 90-110 minutes cycles at night may be continuous with other ‘day cycles.’
Not much evidence for this.
True or false? Infants have REM/nREM cycles.
Sort of, they’re not the same as in adults (different periodicity)
Small animals have _____ REM/nREM cycles and bigger animals (such as humans) have ___ cycles
Small animals have shorter REM/nREM cycles and bigger animals (such as humans) have longer cycles
But there are lots of possible exceptions to this (eg. elephants having a cycle around 70 minutes - though that is guesswork)
- Perhaps these cycles are linked to metabolism, eg. small animal = fast metabolism = fast cycles
Do newborn infants have a circadian rhythm?
No
Hard to say what age a rhythm develops, as this is different from infant to infant
Kleitman had parents record sleep/eat cycle of infants without an imposed schedule on the infant’s behaviour. What were the results?
- At first totally arrhythmic
- A free running rhythm of wakefulness begins
- Circadian clock begins entrainment to day/night
- Infant becomes diurnal
At birth, infants fall directly into ____ sleep
Why
REM
Maybe incomplete circadian system or REM regulation system (ie gating function)