Sleep Flashcards
What are the different ways we measure sleep?
EEG (brain)
EMG (muscle)
EOG (eye movement)
What type of waves is wakefulness characterized by?
Short and spiky alpha and beta waves.
The shortness of spikes means there’s a lot of diff. activity going on.
What type of waves is SWS characterized by?
Big slow delta waves
Synchronized Theta waves
What type of waves is REM characterized by?
Like we’re awake
How long is the ultradian cycle during sleep and wakefulness?
90-120 mins of periods of activity and quiesence
What’s the difference bw alpha and beta waves during our awake state?
Alpha waves is lower frequencies (spikes per second) and higher amplitude. Alpha is long and not as spiky.
-Zoning out
Beta waves are higher frequencies, and lower amplitude. Beta is short and spiky.
-Alert and active
Describe stage 1 of SWS.
Stage 1 - Theta waves; transition between wake and sleep
Describe stage 2 of SWS.
Stage 2 - Sleep spindle; Theta waves are starting look more like Delta waves with high amplitude, low frequency, aka K complexes- signals onset of true sleep.
-Shallow breathing, temperature
If someone wakes you up during stage 2 sleep, what will you say?
You will say that you were awake the whole time.
Describe stage 3 of SWS.
What happens if you are awakened?
Deep sleep - unresponsive to noises.
If awaken, you will be groggy and disoriented.
Theta waves major
Delta waves minor (under 50%)
What’s the difference between the waves in stage 3 and stage 4 sleep?
Difference between 3 and 4 is proportion of Delta waves. In stage 4, delta waves make up over 50%.
Describe stage 4 of SWS.
Delta waves; over 50%.
If awakened, groggy and confused.
What type of stimuli will you be responsive to in REM sleep?
Relevant stimuli like your name or door opening.
When is the first episode of REM sleep?
Around 90 minutes in.
Describe the EEG, EOG, and EMG readings during REM sleep.
EEG - Resembles waking
EOG - Eye movement
EMG - Muscle’s flat
What part of the brain is very active during REM sleep? What isn’t ask active?
Occipital lobe - Low levels of oxygen to frontal lobe; explains why our dreams are vivid but don’t make no damn sense.
If we are losing out on sleep, what is it usually?
After 4 hours, it’s usually REM sleep.
Do we get more REM sleep as infants or as adults?
How about as a toddler?
Adolescent?
Adulthood?
Equal time in REM and SWS.
As a toddler, we decrease REM sleep, same SWS.
Adolescent, REM and SWS is lost.
Adults need less sleep; REM remains constant.
How does our body mark the rhythm and time?
Via the Suprachiasmatic Nucleus - the body’s “master clock” located in the Hypothalamus.
What is the function of the Suprachiasmatic Nucleus?
It marks time and sends signals to other glands and bladder; areas the control other functions.
How does the SCN mark time? Where does it get information from?
It gets information from our eyes - retinas - the retinohypathalamic pathways and projects light information to the SCN.
The retina contains melanopsin- sensitive to light levels.
Why is sunlight dubbed a zeitgeiber? Define zeitgeiber.
Sunlight affects the activity of the SCN; The SCN is entrained to the day-night cycle by zeitgeibers or “timegivers” - helps us keep track of time
What is the proof that external cues, or zeitgebers, affects out circadian rhythm?
Our circadian rhythm appears to be 25 hours - cave experiments, sailors in submarines; etc.
What do we do with the information that the SCN gives us?
It tells us how light it is outside - what we do with that information depends on our species; ie, bats are nocturnal and will sleep during light, while we stay awake during light.
How does SCN keep time; How does light reset its cycle in the morning?
The Suprachiasmatic Nucleus produces 3 proteins: per, tim, and clock.
Per and tim inhibit clock
Clock increases per and tim
When per and tim levels are high, what does this mean?
When per and tim levels are high, they inhibit the levels of clock - and concentration of clock falls.
As clock’s levels falls, it stops promoting the production of per and tim.
Then, per and tim’s concentration begin to fall.
As per and tim’s concentration begin to fall, clock’s concentration begins to rise.
As clock’s concentration rises, it causes per and tim’s levels to rise.
As per and tim’s level rises, clock’s levels fall; etc.
What is lights contribution to per and tim?
Light inhibits the production of per and time.
What promotes per and tim’s levels?
What inhibits per and tim’s levels?
Clock promotes per and tim’s levels
Light inhibits per and tim’s levels.
How does light reset our sleep cycle every morning?
When light levels are high (in the morning), per and tim are inhibited, but clock is high, and then increases the production of per and tim…
What hormone does the SCN regulate?
Melatonin - induces sleepiness.
How do some blind people show normal circadian rhythms?
Because the retina cells in the retinohypothalamic pathways are active - or because they have damage to occipital cortex.
What is Glutamate’s role in sleep?
It is the NT of the retinohypathalamic tract - it inhibits melatonin production.
What helps us wake out of sleep?
Cortisol - it peaks when we wake up.
The dolphins who sleep 1 hemisphere at a time proves what?
That sleep controlling chemical isn’t in the blood…
What is GABA’s contribution to sleep?
GABA = Inhibitory; When the brain is bathed in GABA, we see Delta waves in a specific part of the brain.
Drug’s that act on GABA receptors like benzodiazepines (xanax) are used to treat insomnia.
What is Adenosine’s contribution to sleep?
Antagonist to caffeine… adenosine receptors are everywhere and is part of the metabolism process due to glycogen (muscles love to eat glycogen!)
What are the brain areas and neurotransmitters that are important for wakefulness and sleepiness?
Wakefulness:
1. Pedunculopontine - Acethylcholine
- Basal forebrain - Acethylcholine
- Locus Coeruleus - Norepinephrine
- Raphe nuclei - Serotonin
- Tuberomamillary nucleus - Histamine
- LH - Hypocretin/Orexin
Where is hypocretin produced?
Where does it project to?
What is hypocretins function?
Hypocretin is produced in the lateral hypothalamus.
It projects to the locus coeruleus, raphae nuclei, tuberomamillary nucleus, dorsal pons, basal forebrain; etc…
It functions to activate the brain areas that wake up the brain.
What does degeneration of hypocretin neurons do?
It produces narcolepsy in humans and animals.