Sleep Flashcards
What are the bahavioral criteria for sleep?
- species specific posture
- minimal movement
- reduced sensitivity to outside stimmuli
- reversible to stimmulation
Explain the EEG waves in different stages of sleep
- Awake–> fairly prominentn, small waves
- Stage 1+2–> Non-REM seep (light sleep)
- slows down
- Stage 3+4–> Non-REM sleep, (deeper)
- slow EEG reading waves
- REM Sleep (stage 5)
- indistiguishable from awake EEG
What is a EOG?
When is it used?
It is electro-oculography
–> used to senese eye movements in sleep
Explain the changes in EOG waves in different stages of sleep
- Awake
- Stages 1+2 (light sleep)
- decreased
- Stages 3+4 (deep sleep)
- decrease, but slow waves present
- REM –> very very active, increased
Explain the changes in EMG in different stages of sleep
- Awake
- rapid, a lot of muscle activity
- Stage 1+2
- decreased
- Stage 3+4
- decreased
- REM
- very much decreased
How long is a typicall sleep cycle?
How does it look like?
Normally about 90min (get shorter over night)
- goes from awake via different stage to REM
- From REM goes up again to Stage 2
- From stage 2 (via 3+4 ) to REM
How do HR and respiration change during sleep?
They both decrease during sleep, but increase again in REM sleep
When do dreams occur?
They can occur in any stage of sleep, most likely in REM
What are the characteristics of dreams?
What is their function?
- Dreams are more emotional than awake–> higher activation of limbic system
- Function not known yet but involved in
- memory
- disposal of unwanted memories?
- savety valve for antisocial emotions?
What is the RAS?
Where is it located?
Reticular activating system
It enables conciousness (not site of conciousness)
–> no concrete location known, but sits in brainstem and projects to different parts of the brain
Which systems controll sleep?
- Lateral Hypothalamus
- promotes wakefulness (orexin/hypocretin)
- Ventrolateral preoptic nucleus (anterior hypothalamus)
- promotes sleep
- Suprachiasmatic nucleus
- synchronises sleep with falling light level
Explain the role of the lateral hypothalamus in the control of sleep
It promotes wakefullnes by stimmulating the RAS via orexins (neuropeptides) (american:hypocretin)
Explain the role of the ventral hypothalamus in sleep controll
Ventral hypothalamus (ventral preoptic nucleus) promotes sleep by decreasing RAS activity
Explain the role of the Suprachiasmatic nucleus in sleep regulation
It matches light levels with sleep
- direct + indirect influence on RAS
- stiummulates the pineal gland to produce melatonin (when dark)
- Melatonin decreases RAS activity
What are the results of sleep deprivation?
Sleep deprivation has crucial effects
- psychiatric (depression, stress, mood fluctuation, hallucinations etc.)
- neurological (impaired attention, memory, executive function)
- somatic (glucose intolerance, impaired immunity, increased apptite+ decreased leptin secretion, death)
How does sleep regluation change after sleep deprivation?
- easier to fall asleep
- increase of slow wave sleep (NREM)
- Increase of REM sleep (after selective REM sleep deprivation)
What is the function of sleep?
Not quite known yet
- recovery?
- energy saving?
- specific brain function like memory consolidations etc?
What is insomnia?
Regular problems sleeping
Explain the prevalence, causes and treatment of insomnia
- Very common, mostly transient
- Can be due to
- Physiological: sleep apnoea, chronic pain
- brain dysfunction: depression, shift work fatal familial insomnia (rare)
- Treatment:
- sleep hygene
- hypnotic drugs (enhave GABA)
- sleep Cognitive behavioural therapy (CBT)
What is sleep hygene?
Which factors are involved?
- fixed times
- routine
- no late activity and meals
- only go to bed when tired
- don’t use bed for anything but sleeping
- avoid caffein, nicotine, alcohol late at night
- no napping during day
etc, etc,
What is hypersomina?
Between which two types can you differentiate?
Increased sleepiness
- Primary cause
- post-traumatic brain injury
- narcrolepsy
- ideopathic
- Secondary due to poor night sleep
- Obstructive SA, noctural pain, anxiety, environmental factors (noise), neurodegenerative disease, medication
How can you diagnose hypersomnia?
via the epworth sleepiness scale
–> rates likelyhood of falling asleep in different situations (subjective)
What is narcrolepsy?
- Repeatedly falling asleep during the day and impared night sleep
- might be accompanied by sudden attacks with loss of muscle tone –> Cataplexy (often triggered by emotions)
- possible mechanism: Orexin/hypocretin deficiency
