L1 Hx of sleep medicine Flashcards
1 sleep disorder
sleep deprivation
NOT diagnosible
Leading Theories of Why We Sleep
- Restoration and recovery
- Energy conservation
- Predator avoidance
- Memory consolidation
REMP
Restoration and recovery
Restores biological processes degraded in wakefulness
Increase in growth hormones
Energy conservation
Metabolism drops 5-10%
Endothermy internal regulation of temperature
Sleep needed to offset high energy cost
Hypothalamus regulates body temp
Predator avoidance
Lying still is less likely to attract a predator
Most predators are active at night
Tonic (as in muscle tone) immobility reflex aka animal hypnosis or death feigning – last line of defense against an attacking predator
Total immobilization so animal appears dead - predators not interested in dead prey
Similar to REM sleep when body is almost paralyzed
Reflexes are suppressed
Body temp drops
Memory consolidation
Idea that memories are consolidated best during REM sleep:
Brain cells grow and make neuronal/synaptic connections
Can increase in strength
“Neurons that fire together wire together”
Fine tune binocular vision system
Unimportant memories disappear
Harmless discharge of strong emotions
Activation synthesis theory
Part of memory consolidation theory
dreams occur bc neurons are firing and brain is trying to make sense of it
Who was Robert MacNish and what did he believe?
1834
Author, Philosophy of sleep
Sleep = passive, inactive state of the brain
Sleep occurs bc of lack of stimuli at night/reduced sensory input
Wakefulness occurs bc bombardment of stim from environ
No distinction b/w sleep, paralysis, stupor, intox, hypnosis, etc.
Hypnotoxin theory
19th century fatigue products (toxins and the like) accumulate through the day, finally causing sleep, during which they are gradually eliminated
Who is Nathaniel Kleitman
1928, Founder of sleep medicine
FInds those who are sleep deprived are impaired
People who stayed awake all night will be more impaired at night than next day (no support hypnotoxin theory)
Greatest impairment after 60 hours
Sleep a passive process / the absence of wakefulness
Richard Caton was the first to use…
1875
Physiologist who is experimenting with animals
Put electrodes on animals, can measure brain waves / electrical activity
EEG – electroencephalogram
Used paper to record activity
Hans Berger found..
Recorded electrical activity in the human brain
Sleep could be measured quantitatively
What did Davis and Harvey do/find?
Describe major elements of sleeping brainwave patterns
Take brief samples of brain activity while people sleep
Sleep characterized by high amplitude slow waves
Can happen from ½ per sec to 4 per sec
Wakefulness by low amplitude fast waves (alpha)
14 per second
Evidence for sleep being a passive process
Reticular Activating System
1949
Thought to be endogenous mechanism in brain
Area which stimulates alertness and makes you stay awake
Lesions in the RAS gives delta sleep (very slow like a coma)
Edouard Gelineau discovered?
1880 Discovered Narcolepsy Narke - stupor, unconscious Lepsis - seizure/overtaken Triggered by strong emotion
Richard Henenberg discovered?
1916, Cataplexy - collapse of muscles