Sleep Flashcards
1
Q
sleep debt:
1. def
2. sleep-wake behavior and sleep debt
3. fatigue on cognition
A
- cumulative loss of sleep leading to increased sleep pressure due to inadequate normal sleep
- sleep-wake behavior is modulated by homeostasis control to build sleep pressure during the day when it peaks just before falling asleep and dropping until you wake; sleep pressure increases greatly with sleep debt
- > 16 hours w/o sleep is equivalent to the effect of >0.5 BAC on cognition and vigillance; fatigue leads to increase in human error
2
Q
sleep deprivation:
1. how much sleep is needed?
2. demographics in sleep deprivation in American children
3. defining sleep
4. daytime sleepiness
A
- children (6-13 yrs) req 9-11 h, teens (14-17 yrs) req 8-10 hours, adults (18-64 yrs) req 7-9 h, seniors (65+ yrs) req 7-8 h
- black children have significantly less sleep time than children of other races, white children have the most, higher income have greater sleep times
- sleep latency is the amount of time it takes to fall asleep, mid-sleep disturbance/sleep fragmentation is amount of time awake between periods of sleep over the course of a night, sleep debt is the total of sleep latency nd fragmentation, sleep efficiency is calculated sleep time/time in bed
- indicate problem with sleep quality or quantity
3
Q
acute sleep deprivation and human error:
1. microsleeping
2. memories and attention
3. sleep habits academics
A
- sleep debt induced, brain transitions to deep sleep for seconds, is warning from brain to go to sleep
- sleep restriction impairs memory and increases lapses in attention during psychomotor vigilance tasks and has cumulative effect, does not fully recover after one day of recovery sleep
- increasing sleep duration and consistency correlates to better academic performance
4
Q
sleep v. wake
1. physiological differences
2. EEG
3. neural changes
A
- during sleep body temp, HR, BP, respiratory rate decrease, respiratory rate more regular
- electrodes measure the summation of simultaneous EPSPs of aligned (if not aligned signals cancel out) population of neurons in an area over time, high area, surface signal, low specificity
- during wake, fast, low amp unsynchronized (neurons fire different times) waves, high freq beta (14-30 Hz) with mental activity, lower freq alpha (8-13 Hz) at rest; during sleep, slow, high amp synchronized waves theta (4-7 Hz), deep sleep delta (,3.5 Hz)
5
Q
switching from sleep to wake
1. AAS
2. reg sleep and arousal
3. modulating thalamus activity
A
- sensory feedback of noise, light, temperature change, and movement activates the ascending activating sys (AAS) of the brainstem to send signal to thalamus to activate cortex and stim wakefulness; dmg to AAS can leave person unresponsive and unconscious (coma)
- During wake, VLPO is inhibited by AAS, neurotransmitters released to arouse cerebral cortex by TMN (histamine), Raphe nuclei (SER), LC nuclei (NE), LHA releases orexin to stim wakefulness as backup (orexin deficient in ppl with narcolepsy); during sleep VLPO release GABA to inhibit arousal promoting nuclei, cortex not stimulated, dmg to VLPO results in insomnia
- AAS modulates thalamus activity, during sleep, thalamus releases random bursts of AP to synchronize and slow down cortex activity; during wake, arosual promoting neurotransmitters stim regular single APs to desynchronize cortex activity
6
Q
sleepiness
1. biological clock
2. sleep-wake homeostasis
A
- set by clock genes in superchiasmatic nucleus with inherent tardiness, running on 24.2 hour day w/o time cues; regulated by zeitgebers (environmental cues of time) such as sunlight which causes melatonin to be released to SCN when it is dark to make us sleepy
- sleep pressure is caused by the build up of adenosine in the VLPO from the degradation of ATP, too much adenosine triggers sleep to recover ATP; caffeine block adenosine from binding to receptors to keep you awake
7
Q
good sleep hygiene
A
- set bedtime early enough for 7-9 h of sleep
- keep consistent sleep-wake schedule
- follow nightly routine as time cue for brain to sleep
- turn off electronics, blue light disrupts melatonin production in the suprachiasmatic nucleus
- get daylight exposure to regulate circadian rhythm
- minimize caffeine, avoid 8.8 h prior to bedtime
8
Q
stages of sleep
A
- Stage 1: few minutes, slower theta waves, increased synchrony, drowsy due to high ADP
- Stage 2: sleep spindles interrupt brain rhythm to help ignore external stimuli, high amp K-complex drives deeper sleep by switching the thalamus to burst mode
- SWS/deep sleep: brain recharges ATP, consumes little E, time for repaying sleep debt, delta waves clear toxic residues
- REM: brain awake (fast, low amp, and desynch), body paralyzed to prevent acting out of dreams, vivid and emotional dreams, rapid eye movements
9
Q
sleep cycles
1. overview
2. across lifespan
A
- sleep stages cycle (approx. 5-6 cycles) across the night every 90 minutes, REM increases with each cycle while SWS decreases as more sleep debt is repaid
- SWS start to decline in adolescence while sleep latency increase, why older folks feel less well-rested and can’t clear toxic residues, increasing risk of Alzhemier’s
10
Q
function of SWS :
1. overview
2. sleep deprivation
3. daytime napping
4. fatal familial insomnia
A
- repay sleep debt, regen ATP for next day
- increase time in SWS and delta power to repay debt faster, brain prioritize SWS over other stages of sleep bc essential to gen ATP
- increases sleep latency and decrease SWS time and delta power bc less ATP needs to be regen
- hereditary neurodegenerative disease of the thalamus when it cannot turn off, constantly stim cortex, preventing deep sleep and cannot regen ATP properly
11
Q
function of REM
A
- REM decreases emotional distress caused by memories by desensitizing the amygdala and altering memories
- if not sleeping long enough, lose REM, increase anxiety
- alcohol and cannabis disrupt REM thus feel increased emotional distress post
