Sleep Flashcards
What activities can be described as variable?
brain wave activity
breathing
heart rate
What activities can be described as constant?
temperature
blood pressure
levels of glucose
What decreases in stages of NON-REM sleep?
breathing
What increases in REM sleep?
rate and variability
What are the 3 psychophysiological measures of sleep?
EEG
EMG
EOG
What are EEG recordings characterised by?
frequency and amplitude
What is EMG? - electromyogram
where electrodes are attached to the chin
monitor muscle activity
What does EOG monitor? - Electro-oculogram
eye movements
What type of waves occur when awake?
beta waves
What happens In stage 1 sleep?
slow, light sleep
alpha brain waves
8-12 Hz
experience hypnagogic hallucinations
What happens in stage 2 sleep?
body goes into deep relaxation
theta waves
sleep spindles and k-complexes
12-14 Hz waves
What happens in stage 3 sleep?
delta waves (largest and slowest waves)
1-2 Hz
What happens in stage 4 sleep?
slow wave sleep - like stage 3
deep sleep
How many phases in a sleep cycle and how many cycles does it do?
4 phases
around 5-6 cycles
What is REM sleep?
high brain activity and lack of muscles tone sleep
What percentage of dream recalls happen during awakening from REM sleep?
80%
How long does it take to get into REM sleep?
around 50 to 70 minutes
What has Rem sleep been suggested to evolve with?
homeothermy
maintains stable internal body temperature regardless of external influence
What are the 2 main theories of why we sleep?
- recuperation theories
- adaptation theories
What are recuperation theories?
idea that being awake disrupts the homeostasis (stability) of the body and
sleep is required to restore it
What are adaptation theories?
Sleep is the result of an internal 24-hour clock
Humans have evolved to sleep at night sleep protects us from predators during the night
What symptoms do you get if you don’t sleep?
irritability
blurred vision
problems with concentration
Case study of Randy Gardner (Dement, 1978)
stayed awake for 264 hours then slept for 14 hours
after first night went back to 8 hour sleep schedule
found he didn’t need to catch up on lost sleep
What form does REM sleep tend to be in?
narrative form
What type of theories have been proposed to explain mystery behind dreaming?
psychological
neurobiological
What is the threat-simulation theory? (psychological)
dreaming is a defence mechanism that prepares us for dealing with potential threatening events
threats rehearsed
What is the expectation fulfilment theory? (psychological)
dreaming allows for emotional arousals that haven’t been expressed during the day
What is the activation-synthesis theory? (Hobson, 1989) (neurobiological)
info sent to cortex during REM sleep is random
dream is a result of cortex’s effort to make sense of random signals
What is the continual-activation theory? (neurobiological)
function of sleep is to process, encode, transfer data from STM to LTM through consolidation
When is REM sleep compensated for?
after deprivation
What percentage of NON-REM sleep naps were associated with dream experiences? (Suzuki et al, 2004)
18%
What two factors regulate the amount and time of sleep?
homeostatic drive (bodies need for sleep)
circadian rhythm (biological clock)
How can the control of sleep be described as?
as being allostatic
What is the most well-known circadian rhythm?
sleep-wake cycle
What are the temporal cues in the environment called that keep circadian rhythm on schedule?
zeitgebers
What is the most important zeitgeber?
daily cycle of light
What type of zeitgeber is time?
a cognitive Zeitgeber
What type of zeitgeber is melatonin?
a hormonal zeitgeber
related in the daily light-sensitve cycle
What is adenosine?
a substance that accumulates with waking hours and drives pressure to sleep
What acts as the antagonist of adenosine?
caffeine
What are the 5 key neurotransmitters which can influence where someone lies on the arousal spectrum?
ACh
Norepinephrine
Serotonin
Histamine
Orexin (hypocretin) - neuropeptide
Lin et al (1999) study - hypocretin
studied narcoleptic dogs
isolated gene that caused it
found gene encodes a receptor that binds to neuropeptide called hypocretin
When are Hypocretin neuorns active?
during wakefulness
When are hypocretin neurons inactive?
during sleep
