week 6 sleep Flashcards
(37 cards)
definition of sleep
dynamic and actively produced brain state, with changes to physiology
how do we measure sleep - 3 technical ways and 2 easier ways
- EEG - brain activity
- EMG - muscle activity
- EOG - eye movements
then… sleep headband or wrist-warn trackers
EEG
electroencephalograph
EMG
electromyogram
EOG
electrooculogram
what does EEG reflect
neuronal activity - synchronized (large activity in deep sleep as neurons fire together) or desynchronized (random firing of neurons)
5 types of brain frequencies
- gamma waves 30HZ
alert and concentrating - beta waves 13-30HZ
during most awake activities - alpha waves 8-13Hz
relaxed/sleepy - theta waves 4-7.99Hz
stage 1/2 sleep - delta waves 1-3.99Hz
stage 3 sleep
why do people lucid dream in REM sleep?
due to increased activity -40Hz (gamma waves) in the frontal cortex which is associated with consciousness
why does sleep deprivation affect health?
due to the effects of inflammation and oxidative stress (affects neurogenesis, learning/memory)
what did tucker et al 2006 find about declarative memory
participants learned a declarative task (list of pair words) and a non-declarative task (mirror tracing).
after a nap, with slow-wave sleep, declarative condition had better performance
what did mednick et all 2003 find about REM seep and non-declarative memory
ptsp learned a non-declarative task (visual discrimination)
after a slow-wave sleep, and REM sleep, ptsp who learned ND task improved performance
showing REM sleep improves non-declarative tasks like visual tasks
what did ben Simons et a 2020 find about sleep loss on perceiving threatening situations?
sleep loss makes threats fee more threatening, as the amygdala (fear-center) became more active and the PFC which controls emotions didn’t work as well
even neutral things seem more threatening after no sleep
sleep homeostasis
sleep pressure increases with time awake, due to increases in sleep promoting substances (adenosine).
how does adenosine work?
astrocytes (support cells in the brain), release ATP, which breaks down into adenosine.
adenosine builds up when you’re awake, and attaches to adenosine receptors. when it attaches, it makes your brain activity slow down, making you feel sleepy
what happens when you have caffeine?
caffeine blocks the adenosine receptors, so it can’t attach (preventing inhibitory effect on neural activity). meaning you stay more active
which stage of sleep removes adenosine?
slow wave sleep, but we only know this from mice
we can test this in humans, as people with recessive genes for slower acting enzyme which destroys adenosine, have more slow wave sleep
why does adenosine make you sleepy?
staying awake decreases levels of glycogen as its being broken down into glucose and being used for metabolic reactions. adenosine increases as ATP is broken down which increases sleep pressure.
where is acetylcholine made
pons and basal forebraine
what does acetylcholine do
produces activation and cortical desynchrony when stimulated
where is norepinephrine released
by neurons of locus coeruleus (lower during sleep)
where are serotonergic neurons located
in the raphe nuclei
what does stimulation to the raphe nuclei cause
cortical arousal
what releases histamine
histaminergic neurons located in the tuberomammillary nucleus branch widely throughout the city will cortex and increase cortical activation on the arousal
where is orexin produced
lateral hypothalamus
