module 12 sleep Flashcards
(47 cards)
behavioral definition of sleep
a reversible behavioral state of perceptual disengagement from an unresponsiveness to the environment
sleep is typically (but not necessarily) accompanied by
Postural recumbence
Behavioral quiescence
Closed eyes
neural and physiological definition of sleep
Sleep is a dynamic and actively produced brain state, with accompanying changes to physiology
Sleep is not static or passive!
during sleep, there are alterations in brain __ and secretion of __
during sleep, there are alterations in brain activity and secretion of hormones
sleep is a state of __, separate from wakefulness
sleep is a state of consciousness, separate from wakefulness
stages of sleep overview
Wakefulness
NREM sleep: stages N1, N2, N3 (SWS)
REM sleep: stage R
in which stage of sleep does glucose metabolism peak?
when is it lowest?
REM sleep is peak
lowest in SWS
match the type of wave to stage of sleep
awake
drowsy
NREM stage 1
NREM stage 2
NREM stage 3
REM
awake: beta
drowsy: alpha
NREM stage 1: theta
NREM stage 2: sleep spindles
NREM stage 3: delta
REM: low-voltage, high frequency
wakeful state sleep waves
beta
low-voltage, high frequency
NREM stage 1
very light sleep (2-5% of night)
Transition from Wake to Sleep
Drift in and out of sleep, awaken easily
Hypnagogic jerk: Sense of falling followed by sudden muscle contractions
EEG: low voltage, high frequency
NREM 2
relatively light but maintained sleep (45-55% of night)
Brain activity relatively slower
Breathing and heart rate slowed
EEG: mixed frequency/voltage with occasional bursts of rapid waves (spindles) and delta waves (K-complex)
Spindles
what are sleep spindles?
thalamo-cortical generated bursts of activity; blocking transfer of sensory information/ maintained sleep
why are sleep spindles beneficial?
during sleep we want to be less receptive to stimuli bc we don’t want to be awoken
sleep spindles block __ activity which is responsible for interpreting stimuli
sleep spindles block thalamus activity which is responsible for interpreting stimuli
NREM 3
deep sleep (slow wave sleep; 15-25% of night)
Lower brain activity
High awakening threshold
Deep, restorative sleep; homeostatic sleep
EEG: synchronized cortical activity; high amplitude, low frequency
REM sleep
REM sleep (20-25% of sleep episode)
EEG of REM looks like awake
Brain is very active during REM
Inhibition of spinal motor neurons by brainstem mechanisms mediates suppression of postural motor tonus
Increased heart rate, blood pressure, respiration; sympathetic nervous system dominance
Shorthand definition: “an activated brain in a paralyzed body”
REM sleep is associated with (4)
1) EEG activation (desynchronized cortical activity)
2) muscle atonia (loss of skeletal muscle tone – paralysis!)
3) episodic bursts of REMs
4) Dreams
sleep stages and what percent of night they take up
W: Wake
N1: very light sleep (2-5% of night)
N2: relatively light but maintained sleep (45-55% of night)
N3: deep sleep (slow wave sleep; 15-25% of night)
R: REM sleep (20-25% of sleep episode)
sleep homeostasis simple steps
The longer you stay awake
The more tired you become
The more you need to sleep
*the act of sleeping re-establishes your baseline level
what is necessary to re-establish sleep homeostasis?
slow wave sleep (SWS)
when is SWS prominent?
in early parts of sleep episodes
↑ sleep deprivation = ↑ sleep pressure →
↑ in the driving force pushing the reestablishment of homeostasis which presents as an increase in N3 sleep in early sleep cycles
circadian rhythms definition
body rhythms that have a roughly 24-hour cycle
circadian rhythms regulate
sleep patterns, feeding behavior, hormone release, blood pressure, and body temperature
