Sleep Flashcards
What are the three primary measurements in sleep
Brain, eyes, muscles
- EEG
- EOG
- ENG
What is the frequency range in stage 4 sleep
0.5Hz - 2Hz
Does EMG activity fall during REM sleep
Yes
How long is a typical cycle of sleep
90 minutes
What stage of sleep is related to the hoemostatic process
Slow-wave sleep
What brain region do you need to cut to induce a persistent sleep state
Top of the brain steam
What was Bremer’s argument for sleep
The wake state depends on sensory input and sleep is the absence of that input
What does a lesion to the posterior hypothalamus result in
Excessive sleepiness
What does a lesion to the anterior hypothalamus result in
Insomnia
What region promotes activity in the cortex level
The thalamocortical loop - feedback from thalamus to cortex and back again
During wake, is there a regular pattern on the EEG in the thalamocortical loop
yes
During sleep, is there a regular pattern on the EEG in the thalamocortical loop
no
What frequency is stage 1 sleep activity
4-8Hz
What frequency is stage 2 sleep activity
4-8Hz
What frequency is stage 3 sleep activity
2-4Hz
What frequency is REM sleep activity
> 12 Hz
Is REM sleep frequency the same as wake state
Yes
Was an early theory of sleep that a sensory input to the brain maintained an alert state
Yes
Transectioning ebtween the cerebrum and brain steam causes what
EEG slowing
Transectioning between the cervical spinal cord causes what
Isolated forebrain is active and alert
What region is critical for cortical activation and maintaining wake
Reticular formation
What is the ascending activation system
Thalamocortical loop
What are the cholinergic inputs
Pedunculopontine (PPT)
Laterodorsal tegemntal nuclei (LDT)
What are the monoaminergic inputs
- Norepinephrine
- Serotonin
- Histamine
- Dopamine
What is the main source of norepinephrine
Locus coeruleus
Is locus coeruleus activity high during wake
Yes
Is locus coeruleus activity high during non-REM sleep
No
Is locus coeruleus activity on during REM sleep
No
Is decreased activity in the locus coeruleus linked to slow-wave activity
Yes
Is locus coeruleus activity linked to wakefulness
Yes
What is the origin of serotonergic neurons
Raphe nuclei
Are serotonergic neurons similar to norepinephrine neurons
Yes
Is REM sleep decreased in people taking antidepressants (SSRIs)
Yes
What is the origin of histamine
Tuberomamillary nuclei of posterior hypothalamus
What happens when you block histamine receptors
Sleepyness
Does histamine promote wake
Yes
Dopmaine is related to arousal in what regions
- substantia nigra
- ventral tegmental area
Which type of dopamine receptor is related to arousal
D1
Which type of dopamine receptor is biphasic
D2
What does a low dose of dopamine in D2 result in
Increased wake
What does a high dose of dopamine in D2 result in
Decreased wake
What is the orexin-hypocretin pathway
Part of an input into the arousal system
What does a lack of orexin lead to
Narcolepsy
What does too much orexin lead to
Insomnia
What is the main role of the orexin-hypocretin pathway
To stabilize wake
Of the chloinergin, monoaminergic and oxerin systems which one is the most influential
Orexin
What quietens the thalamocortical loop
(VLPO) Verntrolateral pre-optic area in the anterior hypothalamus
What inhibitory neurotransmitters are related to the VLPO
GABA and galanin
Does the VLPO project to monoaminergic arousal centres
Yes
What does a lesion to the VLPO result in
Less non-REM sleep
Do the VLPO and Monoaminergic regions try to inhibit each other
Yes
What is the controlling pathway in the VLPO vs Monoaminergic dynamic
Orexin
Does the VLPO send inhibitory signals to the orexin and arousal centres
Yes
In sleep, does the VLPO inhibit orexin
Yes
In sleep, does the VLPO inhibit the monoaminergic system
Yes - switches off wake
What processes modulate sleep and wake
Homeostasis and circadian rhythm
What is the homeostatic system
A system that builds sleep pressure during wake and dissipates during sleep
What is the circadian system
A system of ~24hr rhythm that regulates timing, quality and depth of sleep.
What is the wake maintenance zone
Part of the circadian system that maintains aroused state against pressure of homeostatic system
Will you have more slow-wave sleep at night if you are awake longer during the day
Yes
Is slow-wave sleep a marker for homeostasis
Yes
Is theta activity a marker of the build-up of homeostatic sleep pressure
Yes
Is adenosine a marker for build-up of homeostatic sleep pressure
Yes
What is adenosine
By-product of metabolism
What receptor does caffinee block
Adenosine
Are we all fixed to a 24 hr circadian rhythm
No
What happens to your circadian rhythm when you are placed in a dark room with no cues
You go into free-run
What is the master clock of the brain
The suprachiasmatic nuclei
What is the primary entrainment pahtway
Light -> eye -> retinohypothalamic tract -> hypothalamus -> suprachiasmatic nuclei
If you remove rods and cones, does circadian entrainment sitll exist
Yes
What is the primary mechanism in circadian entrainment
IPRGC: intrinsic photosensitive retinal ganglion cells
What happens if you destroy the suprachiasmatic nuclei
YOu destory all biological rhythms
How is melatonin produced
Produced by the pineal gland from info projected from the suprachiasmatic nuclei
How is melatonin measured
Through saliva or plasma
Besides melatonin what is another measure of circadian rhythm
Body temperature
What is a forced de-synchronicity protocol
Force entrainment to a day either very short or long of the 24hrs. This causes free running
Does a forced de-synchronicity change the homeostatic or circadian system
Circadian. Homeostatic remains constant
What is the blood-acholol analogue to shift work
0.05-0.
