Week 5 (B) - Complete Flashcards
(24 cards)
In the context of sleep studies, what was Henri Pieron (1913) all about?
Torturing dogs to develop the Hypnotoxin theory of sleep
What did Henri Pieron do to discover his Hypnotoxin theory of sleep?
Deprived dogs of sleep for 10 days, then took their CSF and injected it into the brain of other dogs. Fucking sadist
What is the main nuero… chemical (?) behind Process S (homeostatic sleep cycle)?
Adenosine
How does Adenosine get broke down?
By adenosine deaminase
regarding which there is genetic variation
Adenosine is the sole factor driving Process S, T/F
FALSE
For one… Dynamics of build up and decay don’t match to process S (exponential function)
Also… Extreme activity that increases adenosine should result in SWS increases but generally not observed.
What is the main other thing after Adenosine that we think influences Process S?
CYTOKINES!!
How are CYTOKINES thought to influence sleep?
- proteins produced by leukocytes and other cells functioning as intracerebral mediators
- interleukin, interferon alpha and tumour necrosis factor have all been shown to promote sleep.
What are the other sleep/immune factors mentioned… there are a whole bunch
- cholecystokinin
- arginine vasotocin
- vasoactive intestinal peptide
- growth hormone-releasing hormone (GHRH)
- somatostatin
- prostaglandin D
The Circadian rhythm has four key properties, list them.
- It is self-sufficient/independent - Persists without time cues
- Its phase can be shifted by light/drugs
- The period can be entrained (if near the intrinsic period)
- It is not impacted by temperature
What THREE variables/ factors/ biomarkers can you look at to observe someone’s circadian rhythm?
- Core body temperature
- Melatonin
- Cortisol
In which brain region is the ‘body clock’?
Suprachiasmatic Nucleus (SCN)
Supra-Chias-Matic Nucleus
What is the Suprachiasmatic Nucleus (SCN) all about?
And how do we know?
It contains the ‘body clock’ that governs circadian rhythm.
Because legions in the SCN disrupt circadian rhythms
The Suprachiasmatic Nucleus (SCN) requires direction neural connections to control circadian rhythms, T/F
FALSE!
It may do so using chemical signals
How do SupraChiasMatic Nucleus (SCN) cells know the time?
The “clock” is set by proteins that inhibit their own production above a certain level.
What are the two inputs to the SupraChiasMatic Nucleus (SCN)?
Basically…
- Light
- Activity
Or in full…
- Melanopsin containing ganglion cells in the retina, a pathway that may account for the ability of light to reset the biological clock (zeitgeber function)
- The intergeniculate leaflet of the lateral geniculate thalamic nucleus, a pathway for other environmental stimuli to set the biological clock (such as activity)
Where does melatonin come from?
The pineal gland
What does the PINEAL Gland produce?
Melatonin
Melatonin is more effective that light at phase shifting the circadian rhythm, T/F
FALSE!
The other way around, massively
The circadian oscillator can be phase shifted WITHOUT affecting short wave sleep (SWS), T/F
TRUE
This is one piece of evidence FOR Process S and C independence
During a forced desynchrony protocol, circadian and homeostatic processes can be separated, T/F
TRUE
This is one piece of evidence FOR Process S and C independence
What are TWO other pries of evidence indicating Process S and C are independent?
- If you nap during the day, you still drop your SWS balance
- Animals with lesioned circadian pacemaker still show homeostatic properties (just no circadian ones)
Provide THREE pieces of evidence against Process S and Process C independence
- In the forced desychony protocol, the two processes seem to interact a bit after all
- Circadian phase does slightly alter about of SWS that happens
- Sleep deprivation actually reduces the phase setting ability of light
What percentage of delta waves so you need on the EEG before you’re classified as being in stage 3?
> 20%
What percentage of delta waves so you need on the EEG before you’re classified as being in stage 4?
> 50%
