sleep Flashcards
what is sleep
- altered form of consciousness
- natural loss of consciousness
features of sleep
- periodic
- rapidly reversible
- distinct from coma, hibernation, anesthesia
stages of sleep
- stage 1-3
- stage 4 (slow wave sleep)
- REM sleep
EEG of awake state
- alpha and beta waves
- high frequency: lots of action potentials/active cortex
- low amplitude: neurons firing out of sync
EEG of stage 1 sleep
- theta activity
- transition of wakefulness to sleep
- EMG: muscles still active
- EOG: gentle eye movements
EEG of stage 2 sleep
spindles: emerge transitioning from light sleep to deeper sleep
EEG of stage 3 sleep
- delta activity appears
- slow wave sleep
EEG of stage 4 sleep
- continuous delta waves
- slow wave sleep
delta activity
- low frequency: few action potentials
- high amplitude: neurons firing in sync
- indicative of quality of sleep and cognitive function next day
EEG of REM sleep
- rapid EEG: brain activity forcing muscles to relax
- EOG: rapid eye movements
- EMG: muscles relaxed
characteristics of stage 1 sleep
- eyes open and close
- person falls asleep
characteristics of stage 2 sleep
sleep deeper
characteristics of stage 3 sleep
- sleep even deeper
- less responsive to stimuli
characteristics of stage 4 sleep
- very deep sleep
- reached within one hour
characteristics of REM sleep
- irregular heartbeat
- shallow breathing
- penile erection or vaginal secretion
- vivid dreams
characteristics of slow wave sleep
- slow EEG waves
- lack of muscle paralysis
- slow or absent eye movements
- lack of genital activity
- banal dreams
sleep deprivation
- aka total sleep deprivation
- remove the ability for animal/human to sleep for a given amount of time
circadian rhythm
- internal biological clock of 24 hour cycle of day and night
- body temperature rises and drops- peak during the day
- altered by age and experience
- changes in energy level, mood, and efficiency throughout the day
- controlled by the suprachiasmatic nucleus in the hypothalamus
suprachiasmatic nucleus (SCN)
- just above the optic nerve
- bright morning light activates light-sensitive proteins that trigger the SCN
- decreased melatonin production in the morning and increased production in the evening (low light)
- damaged: become “free-running”
why do we sleep
- protective role in human evolution
- conserves energy
- restore and repair damaged neurons
- promotes creative problem solving
- pituitary gland secretes growth hormone for muscle development (deep sleep)
- promote function of glymphatic system to clear wastes
sleep restriction
people are allowed to sleep but it is restricted to a specific amount of time
insomnia
inability to start of maintain sleep over at least three nights
sleep apnea
cannot sleep and breathe at the same time
narcolepsy
difficulty maintaining wakefulness
cataplexy
- struck by paralysis but conscious
- triggered by strong emotions
- enter REM sleep as soon as they fall asleep
- feature of narcolepsy
REM behaviour disorder
- older adult acts out REM dreams
- strong predictor of future neurodegenerative disorders
dream
- altered form of consciousness
- sequence of images, emotions, and thoughts passing through a sleeping person’s mind
- usually dream of ordinary events and everyday experiences, most involving anxiety or misfortune
freud’s wish-fulfillment
- satisfaction of a desire
- dreams have a hidden meaning
- dreams express otherwise unacceptable feelings
- critique: dream content is often negative in nature
information processing
- dreams help us sort out the day’s events and consolidate our memories
- critique: sometimes dream of things that we have not experienced or past events
psychological function
- regular brain stimulation from REM sleep -> help develop and preserve neural pathways
- critique: does not explain why we experience meaningful dreams
activation-synthesis
- REM sleep triggers neural activity that evokes random stimuli and memories that sleeping brain weaves into narrative
- critique: individual’s brain is weaving the story -> still tells us something about the dreamer
cognitive development
- dream content reflects dreamers’ level of cognitive development (knowledge and understanding)
- dreams simulate our lives, including worst-case scenarios
- critique: doesnot propose adaptive function of our dreams
