Lecture 14 - Sleep Flashcards
Sleep lab
to see if something is happening during your sleep that’s abrupting your sleep
- monitor brain waves while asleep
- perhaps not getting proper amount of sleep b/c some disruptions
- used for epileptic testing to check brain waves
Sleep purpose
keeps us alive
- we’re best judge if we get enough sleep but sometimes not
Awake
– ALPHA activity, regular, medium frequency 8-12 Hz (more prevalent with eyes closed); BETA activity, irregular, low amplitude 13-30 Hz.
Stage 1
– THETA activity 3.5-7.5 Hz – transition.
- easy to wake up
- starting to fall asleep
Stage 2
– irregular, periods of theta, SLEEP SPINDLES (short bursts at 12-14 Hz – maintenance of sleep), K-COMPLEXES (≈1 per minute).
- little deeper in sleep than stage 1 - still easy to wake up
- people who are recovering alcoholism or drug use have poorly defined stage 2 sleep or those people that have trouble sleeping have problems with this stage
Stage 3
– high amplitude DELTA >3.5 Hz.
Stage 4
– 50% delta activity.
- deep sleep
- difficult to awaken person
Stages 3 & 4
- slow wave sleep.
- sleep talking, walking & night terrors happen here & not during dream sleep
- deep sleep harder to wake up
REM sleep
desynchronized EEG, some theta, rapid eye movements.
body largely paralyzed. (for your benefit)
(dream sleeping - seem real & relatively remembered)
(newborns spend 50% in REM)
90 minute cycle between ___ and ____ sleep.
REM
NON-REM
(rotates through - cycle)
Dreaming
increased cerebral blood flow to visual cortex (visually dominated areas) and decreased to inferior frontal (areas involved in planning of movements)
- protective mech! - level of paralysis, so you don’t act out your dream (ex: fly out window) & hurt yourself
decreased activity (decreased planning, sequencing of events)
increased activity (increased, vivid imagery)
Sleep Disorders - Insomnia
Margaret Thatcher (and Winston Churchill) slept only a few hours a night!
underlying cause – insomnia is a symptom.
medication can be a curse – sleep medication hangover!
sleep apnea – difficulty breathing while asleep (people who snore have brief periods of apnea).
Sleep apnea
– difficulty breathing while asleep (people who snore have brief periods of apnea).
- narrows pipe going down so much so that your brain gets alerted
- at times, palet closes throat & stops O2 going to brain & your brain doesn’t like that so it temporarily wakes you up, so you snort & snore struggle yourself awake to start breathing again
- can happen repeatively during night
- an get v. little sleep b/c every min or so they’re getting woken up by brain b/c not getting O2 they need
Narcolepsy
sleep attack – at inappropriate times (particularly during monotonous or boring conditions).
≈ 2 – 5 minutes.
cataplexy – falling to ground - hypocretin deficiency – dogs.
sleep paralysis and hypnagogic hallucinations (hallucinations during the transitional state between being awake and sleeping) – alien abduction?
Sleep attack
– at inappropriate times (particularly during monotonous or boring conditions). (monotone)
≈ 2 – 5 minutes.
Cataplexy
– falling to ground (kid dancing - happens when kid is excited & fam cheering him on) - hypocretin deficiency – dogs (sleep paralysis at inappropriate times while awake - we go through it at night, REM sleep paralysis)
Sleep paralysis and hypnagogic hallucinations (hallucinations during the transitional state between being awake and sleeping) – alien abduction?
- “awake” but hallucinating, but paralyzed
- think being abducted by aliens b/c they took control over body
- hallucinations combined with paralysis
REM sleep behaviour disorder
acting out! - supposed to be in paralysis like stage
can be quite dangerous – males dreaming their wives are being attacked will hit out at the attacker – sometimes hitting their wives!
women do it too…
- failure to inhibit movement during REM.
- there is a link from REM sleep disorder & PD’s
Slow-wave sleep
usually during stage 4 sleep. (not during REM)
nocturnal enuresis – bedwetting.
somnambulism – sleep walking – different than REM sleep acting out.
pavor nocturnis – night terrors. (screaming)
usually evident in childhood – resolve naturally.
Nocturnal enuresis
bedwetting
Somnambulism
sleep walking – different than REM sleep acting out.
Pavor nocturnis
– night terrors.
Why do we sleep?
brain rest?
only warm-blooded vertebrates exhibit REM.
necessary for survival? – Indus Dolphin. Deal with swift currents (sleep 7 hours a day but in 4 to 60s intervals).
- swims & breathes air so can’t go to sleep in a swift current or else it will drift off or drown
bottlenose dolphin & porpoise sleep one hemisphere at a time!
keeps one hemisphere alert.
- have to breathe air & not sink to bottom so they put half brain to sleep then switch to other
REM
(if we’re denied it 1 night, we’ll try to make up for it in next night)
perhaps slow wave sleep is restorative but REM sleep is important for development (higher portion of REM during stages of development).
consolidation OR clean up? (what we learned for the day)
Largest increase in REM sleep associated with largest increase in performance.
REM sleep increases during exam time. Don’t deprive yourself!
- helps consolidation info there
Sleep over the life span
in general we require less sleep as we get older.
the proportion of REM sleep needed also decreases.
older people may sleep more, b/c body starts deteriorating where you’re sleeping more often
Arousal
– level of alertness (a continuum).
Adenosine
– neuromodulator that plays a role in the initiation of sleep.
Acetylcholine
– agonists increase EEG signs of arousal; antagonists decrease EEG signs.
Norepinephrine
– catecholamine agonists (e.g., speed) increase arousal via noradrenergic system in the locus coeruleus.
Serotonin (5-HT)
– increases relate to locomotion and cortical arousal – facilitating ongoing behaviours.
Histamine
– direct effect on cortex, indirect affect via ACh induced changes.
Describe both sides of aware & alert (sweet spot)
comatose (lower arousal)
nervous breakdown (higher arousal)
Sleep / wake cycles
ventrolateral preoptic area: A group of GABAergic neurons in the preoptic area whose activity suppresses alertness and behavioral arousal and promotes sleep.
areas are reciprocally connected by inhibitory GABAergic neurons.
SLIDE 15 flip-flop
Neural control of REM
REM sleep is controlled by a flip-flop similar to the one that controls cycles of sleep and waking.
The sleep/waking flip-flop determines when we wake and when we sleep, and once we fall asleep, the REM flip-flop controls our cycles of REM sleep and slow-wave sleep.
ACh release in the dorsolateral pons.
basal forebrain connections produce arousal & cortical desynchrony.
REMs arise from connections with the tectum.
- that superiocoleculus that’s imp. for REM is being stimulated & is why we get REM’s when we’re sleeping in REM sleep
Biological Clocks
90 minute activity / rest cycle - more efficient
24 hour sleep / wake cycle
Circannual
yearly
ex: migratory cycles of birds (stimulated by changes in light levels)
Infradian
less than a year
ex: human menstrual cycle
Circadian
daily
ex: sleep/wake cycle
Ultradian
less than a day
ex: eating cycles
Circadian Rhythms
A daily rhythmical change in behavior or physiological process.
zeitgeber – a stimulus (usually the light of dawn) that resets the internal clock responsible for circadian rhythms. (light stimulus) (connection from retina to SCN in brain that brings light info in & helps reset clock)
- passive response to changes in light conditions (living in Resolute would be tough).
- direct projections from retina provide the zeitgeber information about light.
suprachaismatic nucleus (SCN) contains a biological clock that is responsible for organizing many of the body’s circadian rhythms (including sleep/wake cycle).
Seasonal rhythms
breeding rhythms that begin as day lengths increase and end as they begin to decrease. (inspiring b/c gives them all summer to eat & get big & strong before they face next winter)
pineal gland secretes melatonin during the night – more produced during long nights of winter signaling the season.
SADS – seasonal affective disorder – a decrease in melatonin levels? (light therapy may help - flash light on you with light therapy to counteract effects of being dark for so long in winter)
light phase of the circadian rhythm may be too short.
Jet lag
Shift-work - if you keep changing b/t day & night its way harder, than if you just work nights (b/c your body has to keep adjusting) b/c you can sleep during day (& its consistent)
Sleep movie
- while you’re asleep, brain can shift b/t diff stages
- in REM, muscle tone goes to 0 - can’t make muscles work (functionally paralyzed)
- cats & dogs walk in sleep & do beh. they like to do - not random
- can act out dreams - shouting, knocks things over etc. (aggressive) –> REM sleep disorder (caused by gradual disruption of Pons (in BS), which control muscles in REM sleep & the disorder is sometimes a precursor to PD’s - some have v. vivid dreams)
- we dream in non-REM sleep & REM sleep (diff)
- emotions during non-REM sleep - answered questionnaire +ly during non-REM
- emotions during REM related dreams - answered questionnaire -ly during REM
- amygdala is highly activated & is specialized in handling unpleasent emotions like intense fear, anger or aggression
- may be linked to amygdala (linked to our emotions)
- ppl who use depressants go right to REM & stay in it & spend to much time - will have a lot of unpleasant emotion if true
