Chronobilogy/ Sleep and Waking Flashcards
What is the order of the sleep cycle?
stage 1, stage 2, stage 3, stage 4, stage 3, stage 2, REM, stage 2 etc
How do the sleep stages shift as the night goes on?
more REM sleep, less stage 4 sleep
What waves are associated with awake EEG? awake but drowsy?
Beta waves
alpha waves
What waves are associated with stage 1?
theta waves
What waves are associated with stage 2?
theta waves and kappa waves, as well as sleep spindles
What waves are associated with stage 3?
delta waves (20-50% of EEG)
What waves are associated with stage 4?
delta waves (over 50%)
What stage is restorative sleep?
stage 4
What do REM waves look like?
look like awake waves, with sawtooth waves too sometimes
What dominates in REM sleep? What NT is used for this tone to dominate?
sympathetic tone, brain uses NE to make brain more awake even though youre asleep
How does sleep shift across the lifespan?
quantity of sleep decreases, lose stage 3 and 4 sleep
What is melatonin produced by and in response to what stimulus?
produced by pineal gland with loss of light (uninhibition of pineal gland)
What do the MT1 and MT2 receptors for melatonin do?
MT1- lowers brain activity and arousal by suppressing sympathetic drive and RAS
MT2- facilitates 24 hr circadian clock in the suprachiasmatic nucleus
How does cortisol affect sleep?
it peaks in the morning to help awakening, links hypothalamic-pituitary axis to circadian system
What chemicals are wakefulness chemicals? (6)
Ach, glu, NE, DA, 5HT, histamine
What does the basal forebrain (BF) release?
Ach during wakefulness and sleep
GABA to inhibit inhibitory neurons in sleep promoting centers
(promotes wakefulness while lowering sleepiness)
What does the laterodorsal and pedunculopontine tegmental nuclei (LDT/PPT) in the pons release?
Ach to promote wakefulness
What does NE do? Where is it released from?
optimizes attention and task performance while awake, excessive firing causes insomnia and anxiety at night
released from LC
How are blood pressure meds used to treat insomnia?
decrease sympathetic activation to lower effect of NE and lessen nightmares and anxiety
What releases histamine?
tuberomamillary nucleus
What does the H1 receptor do? H3?
H1- leads to wakefulness when stimulated
H3- autoreceptor that inhibits histamine activity to promote sleep
What does stimulating H1 or blocking H3 cause?
wakefulness
Where is serotonin (5HT) released from? What does it generally do?
dorsal raphe nucleus, promotes wakefulness and inhibits REM
What is the circadian clock gene?
5HT 7
Dopamine produced from the substantia nigra does what? from the ventral tegmental area? from the periaqueductal gray?
- SN–> promotes movement
- VTA–> promotes reward
- PAG–> wakefulness
Is orexin part of the reticular activating system?
no, it runs parallel to it and stimulates it when it falters to sustain wakefulness
Where is orexin made? What does it act on?
lateral hypothalamus, acts on LC and TMN
What does the thalamus do in regulating wakefulness/sleep?
coordinates and gates the separate but interacting arousal systems, integrates the systems to spit out either glu or gaba to cortex
Does RAS incrementally increase wakefulness chemicals or do so in an all or none fashion?
incrementally increases (acts like a light dimmer)
What is the suprachiasmatic nucleus?
master switch for sleep/wakefulness, dampens TMN and RAS
What does the orexin system act as?
backup generator if TMN or RAS falters
What are TMN and VLPO? Do they act incrementally or in all or none fashion?
TMN- wake center, VLPO- sleep center
wake/sleep on/off switch, act in all or none fashion
