Sleep Flashcards
1
Q
HOW MUCH SLEEP DO YOU NEED?
A
- most adults need about 7-8h of GOOD-QUALITY sleep p/night
- 0-3 months = 14-17h
- 4-11 months = 12-15h
- 1-2y = 11-14h
- 3-5y = 10-13h
- 6-13y = 9-11h
- 14-17y = 8-10h
- 18-64y = 7-9h
- 65+y = 7-8h
2
Q
SLEEP MECHANISMS
A
- 2 internal biological mechanisms working together to regulate sleep:
1. HOMEOSTASIS (AKA. SLEEP PRESSURE)
2. CIRCADIAN RHYTHMS - caffeine counteracts sleepiness by blocking actions of adenosine
3
Q
SLEEP PRESSURE & WAKEFULNESS: HOMEOSTASIS X CIRCADIAN RHYTHM SLEEP DRIVE
A
- 7am - 11pm = awake; sleep pressure ramps up more as day goes on
- 11pm - 7am = sleep; sleep pressure drops
- circadian rhythms = physical/mental/beh changes over 24h cycle
- circadian rhythms also follow this flow via wakefulness IF homeostasis & circadian processes = synchronised
4
Q
AVERAGE TEEN CIRCADIAN RHYTHM
A
3AM-7AM: THE BIG DIP
- energy = lowest; may not feel fully awake until 9-10am
10AM-1PM: ENERGY UP
- body temp rises throughout morning aka. alertness/sharpness increase
2PM-5PM: AFTERNOON SLUMP
- may crave snacks; earlier for adults (1-3)
11PM: GETTING SLEEPY
- melatonin (sleep hormone) rises hour later in teens; blue light suppresses it aka. disrupts sleep
5
Q
SLEEP ANATOMY
A
- HYPOTHALAMUS
- control centers affecting sleep/arousal - SUPRACHIASMATIC NUCLEUS (SCN)
- receive info about light exposure; control beh rhythm - BRAIN STEM
- communicated w/hypothalamus to control transitions between wake/sleep - THALAMUS
- relays info from senses -> cerebral cortex - PINEAL GLAND
- receives signals from SCN; increases melatonin production - BASAL FOREBRAIN
- promotes sleep/wakefulness - AMYGDALA
- becomes increasingly active during REM
6
Q
GOOD SLEEP = CRITICAL TO EXECUTIVE/COGNITIVE FUNCTIONING
A
FRENDA & FENN (2016)
- WM abilities
DEAK & STICKGOLD (2010); DIEKELMANN (2014)
- LTM consolidation
WHITNEY ET AL. (2017)
- attentional control
ALHOLA & POLO-KANTOLA (2007); DURMER & DINGES (2005); RAVEN ET AL. (2018)
- general cognitive performance
7
Q
SLEEP & AGEING
A
YANG, XIE & WANGE (2022)
- sleep duration impacts neurocognitive development in childhood/adolescence
DZIERZEWSKI ET AL. (2018)
- declines in sleep & cognitive performance occur w/ageing
8
Q
SLEEP DEPRIVATION VS RESTRICTION
A
- total sleep deprivation = extended continuous wakefulness for 24-72h
- sleep restriction = restricted sleep time/getting less than recommended
- sleep fragmentation = short interruptions to sleep
9
Q
ATTENTION
A
- brain regions & networks associated w/attention/WM/executive functions:
1. frontoparietal network (FPN)
2. thalamus (arousal)
3. default mode network (DMN) - all affected by sleep deprivation
- robust/reliable reductions in functional MRI signal in dorsolateral prefrontal cortex (dIPFC)/intraparietal sulcus while performing attentional tasks = consequence of sleep deprivation
10
Q
BEHAVIOURAL CONSEQUENCES
A
- activity in thalamus during sustained attention tasks = altered following total sleep deprivation
CHEE ET AL. (2010); TOMASI (2009) - greater activity under sleep loss conditions
CHEE (2010); CHEE (2008) - intermittent periods of diminished thalamic activity
11
Q
KRAUSE ET AL. (2017)
A
- sleep-deprived human brain
- thalamus represents pivotal gating hub via which alterations in brainstem ascending arousal signals affect cortical attentional networks
- elevated thalamic activity under sleep loss = frequently maintained attentional performance
- substantial reductions in thalamic activity = common lapses in attention
- observed reductions in thalamic activity = NOT present during attentional lapses in well-rested conditions
12
Q
WORKING MEMORY
A
- WM & attention systems overlap
- deficits in WM correlate w/reductions in DLPFC/posterior parietal activity
- degree of aberrant on-task DMN activity preducts severity of WM impairment in sleep-deprived individuals
- adolescents reporting poorer sleep quality (BUT still within normal range) than peers exhibit less DLPFC activation during cognitive control task
13
Q
REWARD PROCESSING
A
- mesolimbic reward system = network of interconnected brain regions (incl. midbrain vental tegmental area/striatum/PFC regions)
- ventral tegmental area provides dopaminergic innervation to striatum connected to/regulated by areas of PFC (particularly medial PFC (mPFC)/inferior orbitofrontal cortex (OFC) regions)
- guide motivated actions/learning
14
Q
SLEEP DEPRIVATION IN REWARD PROCESSING
A
- mesolimbic reward system = sensitive to sleep loss -> increased risk taking/impulsivity
- 1 night of sleep deprivation -> increased activity in ventral striatum in mixed monetary gamble task during anticipation/receipt of monetary rewards
- activity in affect-related regions in frontal cortex associated w/valuation/salience (incl. insula/mPFC) = also substantially increased following sleep loss
15
Q
REWARD PROCESSING PAPERS
A
- sleep deprivation -> generalised increase in reward sensitivity impairing reward discrimination accuracy
- fMRI signal in mPFC/OFC/anterior insula cortex in sleep-deprived individuals DOESN’T accurately discriminate between trials (not) involving monetary reward/punishment values
KILLGORE (2006); GUJAR (2011) - sleep-deprived individuals make more risky decisions & assign greater weights to recent rewards
- responses in striatum/amygdala to emotionally pleasurable/hedonic images + desirable food stimuli = amplified during sleep deprivation
16
Q
SUMMARY I
A
- sleep loss = associated w/increased reward processing & impulsivity due to hyperactive reward systems
- sleep loss = also assocyaed w/widespread impairments in cognitive task performance & reductions in dlPFC activity
17
Q
SHIFT WORK
A
- 2-3h sleep loss p/night accumulated over multiple nights -> deficits of performance (ie. sustained attention) particularly w/limited opportunity for sleep recovery
- reductions in sleep duration impair performance even more in magnitude to alcohol intake
- relevance of sleep-induced effects on cognitive function = night shift workers may be chronically sleep restricted partly dur to circadian misalignment
18
Q
CIRCADIAN RHYTHM SLEEP-WAKE DISORDERS (CRSWD)
A
- disruptions to circadian rhythm can occur over short/long-term
- experts identified number of circadian rhythm sleep-wake disorders (CRSWD) based on characteristics/causes:
1. JET LAG DISORDER
2. SHIFT WORK DISORDER
3. ADVANCED SLEEP PHASE DISORDER
4. DELAYED SLEEP-WAKE PHASE SYNDROME
5. NON-24-HOUR SLEEP WAKE DISORDER
6. IRREGULAR SLEEP-WAKE RHYTHM DISORDER
19
Q
CRSWD: JET LAG DISORDER
A
- occurs when person travels across multiple time zones in short period of time
20
Q
CRSWD: SHIFT WORK DISORDER
A
- work obligations can cause major disruptions in person’s circadian rhythm
21
Q
CRSWD: ADVANCED SLEEP PHASE DISORDER
A
- rare
- people w/it get tired early in evening & wake up very early in morning even when they want to be up later at night/sleep later in morning
22
Q
CRSWD: DELAYED SLEEP-WAKE PHASE SYNDROME
A
- associated w/staying up late at night & sleeping in late in morning
23
Q
CRSWD: NON-24-HOUR SLEEP WAKE DISORDER
A
- occurs primarily in blind people
- aka. aren’t able to receive light-based cues for circadian rhythm
- body still follows 24h cycle BUT sleeping hours constantly shift backward by minutes/hours at a time
24
Q
CRSWD: IRREGULAT SLEEP-WAKE RHYTHM DISORDER
A
- rare
- no consistent pattern of sleep
- may have many naps/short sleeping periods throughout 24h day
- frequently connected to conditions affecting brain (ie. dementia/traumatic brain injury (TBI))
25
HEALTH IMPACTS OF DISRUPTED CIRCADIAN RHYTHMS
- circadian rhythms influence:
1. sleep patterns
2. hormone release
3. appetitie & digestion
4. temperature
- long-term sleep loss & continually shifting circadian rhythms can increase risk of:
1. obesity/diabetes
2. mood disorders
3. heart/blood pressure issues
4. cancer
5. worsening of existing health issues
26
SLEEP LOSS x IMMUNE SYSTEM
1. natural killer (NK) cell function decreases -> viral infection/cancer risk increases
2. inflammatory cytokines increase -> cardiovascular/metabolic disorders increase
3. antibody production decreases -> common infection risk increases
27
2H OF SLEEP LOSS
- increased insulin resistance/leptin/ghrelin lvls & increases in evening cortisol lvls post (as little as) 2h sleep loss
- increase in ghrelin/leptin -> increased hunger/food cravings
28
MAINTAINING HEALTH SLEEP-WAKE CYCLE GUIDELINES
- get sunlight
- exercise
- keep naps short
- avoid caffeine
- avoid using electronics in beg
- build consistent sleep schedule
29
SLEEPWALKING & PARASOMNIAS
- cerebellum/brainstem DON'T "shut off" same as other brain parts
- integration of info between dif parts of cerebral cortex = considered important precursor for consciousness
- brain = awake enough to perform v complex/oft protracted motor/verbal behs BUT asleep enough not to have conscious awareness of/responsibiloty for such behs
