5) Sleeping & Dreaming Flashcards
Identify the different stages of sleep and the neural activity
Awake - alpha & beta waves
Stage 1
- lightest sleep
- theta waves
- half awake
- hypnagogic imagery: scrambled dream-like images
- Sudden jerks of movement
Stage 2
- Sleep spindles & K complexes
(Sudden bursts of electric activity & sharp rise/fall waves)
- Breathing and heart rate even out = rhythmic
- Body temp decreases
- Muscles relax, eye movements stop
Deep sleep - Stage 3 & 4
- Slow large delta waves
- Blood temp & heart rate falls, breathing slows even more
- Sleepwalking
describe our sleeping pattern
cycle btwn diff stages (1232R232 etc)
If we stay asleep, don’t go back to stage 1
Cycle about every 90 minutes
More slow wave sleep early on
More REM sleep later as we get closer to waking
NREM
Sleep associated with stages 1 to 4, no rapid eye movement
Dreaming is less vivid and less frequent, but can still happen!
Dreams are shorter and thought-like, less emotional
Slow wave sleep
Stage 3 & 4 cuz of slow delta waves
Needed to feel fully rested
Alcohol suppresses delta wave sleep :(
REM
Sleep where brain is most active and vivid dreaming occurs most often
Dreams are emotional & illogical
Get more REM as night progresses
Activity
Low amplitude, high frequency EEG similar to stage 1
Activity increases to waking levels in brain & ANS
ex/ increased temperature, blood pressure, heart rate
Effects on muscles
Loss of muscle tone
Some muscles activity (twitch) but mostly paralyzed (Paradoxical REM)
Hypothesized it’s to protect us from acting on our dream
functions of REM
- Important for mental health
- Necessary for processing of memories
Mysteries:
How do ppl benefit from this high-energy consuming process
Why is it that drugs suppressing REM seem to produce no ill effects?
Why do babies display so much REM-like sleep?
Default Theory of REM
REM is a break btwn bouts of NREM
Maintains some awareness of external stimuli, allows us to check in with envo that would not be possible during NREM
REM prepares for wakefulness (hence the prominence of REM towards end of sleep)
Theories of Sleep
- Recuperation theories
Something important happens in sleeps, it serves a function
Being awake disrupts homeostasis, sleep restores it and recover
ex/ energy levels, repair injuries, fight infection - Adaptation theories
No physiological functional purpose
Circadian rhythm - Sleep is a result of 24 hour cycle scheduled by envo cues
Evolutionary standpoint, protects us from accidents & predation
Conserve energy
Free Running Rhythm
When not exposed to any environmental cues, still maintain approximately 24 hour cycle through evolution
Body show same biological patterns, rlly hard to mess with circadian rhythm
Circadian rhythm
Sleep is a result of 24 hour cycle scheduled by envo cues
rlly hard to mess it up
Biological clock: SCN in hypothalamus that controls our alertness
Comparative analysis of sleep
- Sleep does serve a physiological function
Not just to protect from predators - Sleep not only for higher order human function
Doesn’t only serve to release emotions to ensure good mental health - Sleep needed for survival but not in great amounts
Less during migration, mating, no food, etc
Sleep more in captivity cuz don’t have to look for food or worry about being hunted - No strong relationship between sleep length & body size, energy use, temp
Carnivores sleep the most, then omnivores, then herbivores sleep least
What are the general effects of not sleeping properly?
Physical health
Impaired immune system
Increased heart rate (sympathetic nervous system activation)
Hormone dysregulation (appetite)
Mental health
Cognitive impairment, attention deficit
Memory lapse / loss
Hallucination
Emotional health
Irritable, anxious
Inability to handle stress
Total sleep deprivation
Skip entire night of sleep
Know that we feel terrible
Leads to increased efficiency to get stage 3 & 4 sleep
- Regain most of stage 3 sleep
more slow wave sleep, even in naps
Less stage 1 & 2 - Adjust to get same amount of slow wave sleep
Tells us slow wave sleep is important - Waking during stages 3 & 4 cause sleepiness, but waking during REM does not
Chronic sleep restriction
Less sleep than normal or optimal
Same as deprivation but less self awareness
(report feeling normal, but can see deficits if tested)
Effects found in Human Experiments:
- Sleepier
- Fall asleep quickly if given the chance
- Can encounter microsleeps - Disturbed mood
- Poor vigilance
micro sleeps
nodding off, really short sleeps
Chronic sleep disruption
Sleep length is fine, but repeated disruptions, always waking up
Same effects as deprivation but more severe & chronic
What are 3 ways of not sleeping properly
total sleep deprivation
chronic sleep restriction
chronic sleep disruption
Rem deprivation studies
Deprive one of REM sleep by waking each time a bout of REM begins
- Greater tendency to initiate REM cuz been deprived of it
- Greater than normal amounts of REM sleep during subsequent nights of sleep
(REM rebound)
What is a confound that affects our sleep?
stress!
What is the ideal amount of sleep?
7-8 hours is ideal
Shorter sleepers and longer sleepers were correlated with greater risk for mortality
Common beliefs about dreaming
- External stimuli become incorporated into dreams
- Most stimuli are neither incorporated into dream nor elicit behavioral response
- Certain stimuli more likely to be incorporated
(Spraying water, pressure on limbs, meaningful words) - Sleeptalking and sleepwalking (somnambulism) occur during dreams
- Dreaming usually in REM, that’s when we are paralyzed
- Sleep talking can happen at any stage, but likely early stages (waking up or REM)
- Sleepwalking typically happen in slow wave sleep - Dreaming only occurs in REM
- Dreaming actually occurs in stages 1, 2, & 3 too
- More thoughtful, shorter, less vivid, not typically what we remember
- Dreaming happens without REM, and REM happens without dreaming
Why do we dream?
- Activation Synthesis Theory
- Brain trying to make sense of its own random activity during sleep (cuz pons transmit random signals -> thalamus -> forebrain) - Virtual Trainer
- Dreaming stimulates the brain, allows us to practice things from real world in mind (simulation) - Attempt to organize unconsciously reactivated memories
- becomes some kind of story
Lucid dreaming
Feel like we awake and have control over the dream
Can stimulate with gamma rays to increase likelihood to enter lucid dreams
Can actually practice some skill and improve
Dream protection theory
Manifest and latent content
Dreams help keep sexual & aggressive instincts at bay by repressing them
