B7-048 Sleep, RAS Flashcards
target of reticular activating system
cerebral cortex
(like the switch to turn the cortex on, if it doesn’t turn on you can’t wake up)
serves as the source of the reticular activating system
goes to thalamus –> cortex
rostral reticular formation
diffuse projection systems involved in the regulation of sleep and wakefulness [4]
cholinergic
noradrenergic
serotonergic
dopaminergic
pattern in which EEG electrodes are arranged
montage
frequency of bands: beta
more than 12
(low amplitude, high frequency)
frequency of bands: alpha
8-12
(high amplitude, lower frequency)
frequency of bands: theta
more than 4 but less than 8
frequency of bands: delta
less than 5
[…] activity occurs during alert wakefulness
beta
[…] activity occurs during relaxed wakefulness with eyes closed
alpha
two EEG activities associated with wakefulness in normal adults
beta
alpha
alpha rhythm is largest over the […] lobes [3]
parietal
occipital
posterior temporal
beta rhythm is most prominent over […] of the brain
front
[…] rhythm is replaced by […] rhythm when eyes are opened
alpha rhythm is replaced by beta rhythm when eyes are opened
what is being recorded in EEG?
changes in resting membrane potential in neurons
thalamic reticular nucleus neurons are
gaba-ergic
receives excitatory input from the thalamocortical and corticothalamic axon collaterals
thalamic reticular nucleus
activity of the […] synchronizes the rhythmic activity of cortical neurons
thalamic reticular nucleus
(pacemaker)
EEG waveform seen in Stage 1 (drowsy) sleep
alpha drops out
theta waves
EEG waveform seen in Stage 2 sleep
sleep spindles and k-complexes
EEG waveform seen in Stage 3 sleep
delta waves
(slow wave sleep)
the EEG appearance in REM
is like the awake EEG
synchronized vs. desynchronized EEG patterns
synchronized: high amplitude, low frequency (alpha and delta rhythms)
desynchronized: low amplitude, high frequency (beta rhythm)
when do you remember dreams?
when you wake up right after a REM cycle
how does sleep change in the elderly?
less slow wave sleep
more nighttime awakenings
how do sleep cycles look in children?
more time spent in slow wave sleep
a sleep cycle is about […] min
90
metabolic rate and brain temperature are at their lowest in […] sleep
slow wave
sympathetic output decreases and muscle tone is low in […] sleep
slow wave
weird dreams occur during what phase of sleep?
REM
irregular changes in heart rate, blood pressure, and breathing occur during […] sleep
REM
atonia occurs during […] sleep
REM
active inhibition of alpha motor neurons via reticulospinal tracts
atonia
physiologically, what is the purpose of atonia during REM?
so you don’t act out your dreams
sleep and wakefulness occur in […] cycles
24 hour
(would still occur in environment without exogenous stimuli)
pacemaker for circadian rhythm
suprachaismatic nucleus
(in anterior hypothalamus)
light sensitive retinal ganglion cells that input into the retinohypothalamic tract to regulate circadian rhythm
melanopsin
describe the pathway to release melatonin
suprachiasmatic nucleus –> pineal –> melatonin
hypothesis about why sleep is necessary [2]
slow wave sleep is important to restoration
REM sleep is important to memory consolidation
inability to fall asleep
often has a learned behavior component
insomnia
abnormal behaviors during sleep
parasomnias
difficulty transitioning from sleep to wakefulness
sleep inertia (parasomnia)
(set multiple alarms)
sleep walking, talking, eating, terrors, and periodic leg movements of sleep occur during […] sleep
slow wave (type of parasomnia)
fairly common cause of excessive daytime sleepiness
periodic leg movement of sleep (parasomnia)
failure of REM paralysis mechanism
REM sleep disorder (parasomnia)
**sometimes a precursor to parkinsons or Lewy body disease
extrinsic circadian rhythm disorders are caused by [2]
time zone change
work schedule change
intrinsic circadian rhythm disorders [4]
delayed sleep phase (night owls)
advanced sleep phase (early birds)
non-24-hour sleep wake syndrome
irregular sleep/wake rhythm
falling asleep in embarrassing or dangerous situations
pathologic sleepiness
test for pathologic sleepiness
multiple sleep latency test
(positive if average time to fall asleep is less than 8 min)
causes of poor quality of sleep [3]
sleep apnea
PLMS
parasomnia
causes of inadequate quantity of sleep [2]
“voluntary”
insomnia
most common cause of excessive daytime sleepiness
obstructive sleep apnea
if the quality of sleep is okay, what are the possible causes of excessive sleepiness? [2]
narcolepsy
idiopathic hypersomnolence
tests quality of sleep
polysomnogram
full syndrome of narcolepsy [4]
- daytime sleepiness
- cataplexy
- sleep paralysis
- hypnagogic hallucinations
(don’t have to have all 4)
abrupt and reversible loss of muscle tone elicited by strong emotion
caused by wakeful activation of REM paralysis
cataplexy
(seen in narcolepsy)
immediately enter REM sleep when first going to sleep
narcolepsy
(normal individuals enter non-REM sleep first)
believed to keep brain systems needed for wakefulness from shutting down
narcolepsy is hypothesized to be an autoimmune reaction to this substance
orexin
which stage of sleep provides neurons with the most rest?
slow wave sleep
(low metabolic rates and temperature)
what do EEGs record?
changes in potential difference between two electrodes
After what stage of sleep are you most likely to awaken?
REM
most common period of sleep before spontaneous awakening
REM
what is the source of electrical activity in EEG?
sum of all excitatory and inhibitory postsynaptic action potentials
what nucleus is believed to result in synchronization of the resting membrane potential of cortical neurons?
thalamic reticular nucleus
“pace-maker” that causes the synchronization of resting membrane potential of cortical neurons
thalamic reticular nucleus
most common cause of excessive daytime sleepiness in adults
sleep apnea
circadian rhythm is driven by the […] nucleus
suprachiasmatic
what EEG waveform has the highest frequency and lowest amplitude?
beta
what EEG waveform is seen in awake patients with eyes open?
beta
what EEG waveform is seen in awake patients with eyes closed?
alpha
what EEG waveform is seen in Stage 1?
theta
what EEG waveform is seen in Stage 2?
sleep spindles and K complexes
what EEG waveform is seen in Stage 3?
delta
what EEG waveform has the lowest frequency and highest amplitude?
delta
what EEG waveform is seen in REM?
beta
patients with narcolepsy have decreased REM […]
latency
extraocular movements occur during REM sleep due to activity of
PPRF
what stage of sleep is thought to serve memory processing function?
REM
what stage of sleep does teeth grinding occur?
2
what stage of sleep does sleepwalking, bedwetting, and night terrors occur?
3
a lesion in the […] would cause reduced levels of arousal and wakefulness, or coma
reticular activating system
