Flashcards in Sleep Phys and Disorders Deck (50):
What part of the brain, in very general terms, regulates sleep?
See slide 5 for ambient light summary
Body temperature does what during sleep periods?
Growth hormone is released most when?
Just after we fall asleep
Cortisol is released most when
Just before we wake up
Method of measuring sleep is known as
How many stages of sleep are there
What are the different divisions of EEG frequency
Beta- Over 13 hz
Alpha- 8-13 hz
Theta- 4-7 hz
D- less than 4
Beta frequency EEG
Over 13 hz. Most commonly seen in normal awake human beings
As frequency falls, what happens to ampltude>
So, basically as you progress from "Awake" through stage 4, the frequency of the EEG falls while the amplitude of the waves rise.
What is unique about the EEG in REM sleep?
It is appears to be very similar to that of the awake sleep
Stages I-IV together are called
Non- REM sleep
Stage I is the lightest sleep and stage 4 is the...
Sleep spindles and K complexes are characteristics of what stage of sleep
What type of EEG activity characterizes stage I and II of sleep?
Stage 3 and 4 sleep are characterized by what kinds of EEG waves
The duration of sleep in stages 3 and 4 is longest when?
Early in a sleep cycle
The duration of REM sleep is longest when>
Late in the sleep cycle
Compare Non-REM with REM. Physiologically
NREM- Eye movements are slow, movement occurs but muscle tone is decreased
- Decreased BP, HR, RR, metabolic rate
- Dreams less vivid, low emotional content
- Sleep walking and night terrors occur during slow wave
- All reach a maximum during Stage IV sleep
- Rapid eye movements
- muscle paralysis
- HR, BP, RR, temp and metabolism approach awake level
- Dreams Vivid, high emotional content
Penile and clitoral erection occur when?
During REM sleep
Brain activity is increased where during REM sleep?
_ Amygdala, parahippocampal gyrus, anterior cingulate cortex
What brain areas are inhibited during REM
- Frontal Cortex and posterior Cingulate cortex.
What is the significance of these active and inactive brain regions
- The activity explains the vivid, emotional dreams that occur during REM.
- The inhibition of the certain brain regions may explain the bizarre nature of some dreams due to reduced executive reasoning and ratinal thought
Make a chart for the Neural sleep circuits
The Neural sleep Circuit that is Cholinergic in nature is
- Cholinergic neurons from the pedunculopontine (PPT) and Lateral Dorsal Tegmental (LDT) project to the thalamus and other brainstem areas.
- Triggers thalamic cortical signaling that produces high frequency, low voltage EEG activity consistent with arousal.
- Also active during REM sleep
Noradrenergic sleep circuit?
Noradrenergic input comes from the locus ceruleus to the neocortex
Highly activated during wakefullness, none during REM
Dopaminergic wakefullness cicuits originate where?
This circuit is most important for full wakefullness
Serotonergic circuits originate where?
dorsal and medial raphe nuclei
Histaminergic output during wakefulness comes from
What is important about the Orexin pathway
90% of pts with narcolepsy have significantly decreased or undetectable levels of orexin
Ventrolateral preoptic nucleus
Significant because it harbors GABAergic and Galanin neurons both of which innervate and inhibit all of the nuclei that activate arousal. Thus, activation of the VLPO causes decreased forebrain arousal and the onset of NREM sleep
Lesions of the VLPO would lead to
What are somnogens
endogenous sleep- promoting chemicals that may accumulate during wakefulness and promote sleep onset.
a somnogen that builds up in the CNS during wakefullness and declines during sleep
Cytokines IL-1B and TNF
synthesis turned on by decreasing light
Multiple sleep latency test
EEG defined sleep latency, i.e, the time required to fall asleep during 4-5 daytime naps
Epworth sleepiness sclae
self-reported tendency to fall asleep in 8 diff situations
Obstructive Sleep Apnea
Repetitive blockage of the resp pathway during sleep causing apneic periods lasting
- Longer than 10 senconds
- and causing oxyhemoglobin desaturations of more than 4%
Strong association b/w OSA and
heart disease and HTN
Check out OSA phys findings and symptoms slide
- May have:
Pitting Edema with large hands and feet
Snoring, heartburn, memory loss, depression, nocturia, impotnece
Excessive daytime sleepiness associated with one or more of the following tetrad:
- sleep attacks/ intrusions
- cataplexy- abrupt loss of muscle tone
- sleep paralysis- persistent REM sleep atonia after waking
- hypnagogic hallucinations
90% of ppl with narcolepsy develop it when
by 2nd or 3rd decade
Pathogenesis of Narcolepsy
loss of hypocretin/orexin secreting neurons in the posterior lateral hypothalamus
- related to HLA genes DQ1 and DQB1 that may predispose to autoimmune attack on orexin secreting neurons
Dx of narcolepsy
- clinical pres
- Low CSF hypocretin level
REM sleep behavior disorder
- Loss of atonia/paralysis during REM sleep.
- Very rare, most common in adult males over 50
See slide for pathogenesis info
Melatonin produced where
Sleep Cycle Stage Progression
Awake- stage 1 - stage 2- stage 3- stage 4
Back to 3, 2, 1 etcc... periodically moving into REM