Brain Rhythms and Sleep 2: Neural mechanisms + sleep disorders Flashcards
neural mechanisms of sleep
what 3 types of neurotransmitter system neurones are critical to sleep-wake cycle
- serotonin
- noradrenaline
- acetylcholine
wakefulness and ascending reticular fomation
what neurotransmitter do midbrain neurones release
histamine
wakefulness and ascending reticular
what do diffuse modulatory neurotransmitter systems do
synapse with the thalamus and cerebral cortex to increase neuronal excitability and suppress rhythm firing (to stop sleep)
falling asleep and NREM state
what pathways decrease and increase in firing rate when you fall asleep
General decrease in firing rate :
of most brain stem modulatory neurons (NA, 5HT and ACh)
increase of firing rate in basal cholinergic neurons
sleep promoting factors
what is sleep pressure?
every minute your awake, the higher your adenosine levels
adenosine acts on sleep promotoing centres and turns off wakefulness centres
when adenosine concentration peak there is an irresistable urge to go to sleep
sleep promoting factors
why is caffeine able to temporarily reduce sleep pressure?
it is an adenosine receptor antagonist
sleep promoting factors
what is the average half life of caffeine?
5-7 hours
Sleep disorders
what happens in Rapid eye movement disorder
- pontine reticulospinal pathway in Pons in brainstem, which prevents acting out of dreams, fails to inhibit muscle tone during REM sleep, so dreams are acted out.
sleep disorders
what is narcolepsy
sleeping at times and places where sleep does not normally occur
sleep disorders
what is sleep apnea
- interruption of breathing and decline in oxygen level of blood which leads to easy arousal from sleep or results in lighter stages of NREM sleep to maintain breathing.
sleep disorders
what device can be used to gently blow air into the airway to keep them open during sleep
- a continuous positive airway pressure device (CPAP)
sleep disorders
what is insomnia and what is considered chronic
inability to fall asleep despite appropriate opportunities to do so
chronic is considered more than 3 weeks
