sleep Flashcards
what are the behavioural criteria of sleep
minimal movement
sterotypic/species specific posture - atonia
reduced responsiveness to external stimuli
reversible with stim
wat are the stages of sleep *
awake
stage 1 and 2 - non rem (NREM)
3 and 4 - NREM
5 - REM
what does an emg show
muscle activity around teh jaw
what does an eog show
eye movement
what is a feature of stage 3 and 4 sleep *
slow HR and rhythm
what is a feature of stage 5 sleep *
REM
busy eog
HR increase
eeg - similar to awake- rapid
usually when dreaming
what is the length of a sleep cycle *
90mins
feature of stage 2 sleep *
sleep spindle on eeg - like a signiture - buts of energy
describe the maintenance of arousal *
reticular actiavting system controls consciousness - enables consciousness, but not where consciousness is stored
stems from brainstem and projects to thalamus and cortex
describe the control of the sleep wake cycle *
lateral hypothalamus promotes wakefulness - using neurotransmitters orexin/hypocretin - stimulates the reticular activating system and keeps you awake
ventrolateral preoptoc nucleus (anterior hypothalamus) promotes sleep - negative force on RAS
explain how sleep is syncronised to day length *
supraciasmatic nucleus synchronises sleepo with falling light level
level of ambient light is tracked and fed into system
suprachiasmatic nucleus stimulates melatonin release when dark from pineal glands - makes you sleepy
what are the effects of sleep deprivation *
psychiatric and neurological - sleepiness, irritability, stress, mood fluctuations, depression, impulsivity (siezures and convulsions), hallucinations
neurological - impaired attention, mem and executive func, risk of errors and accidents, perhaps neurodegeneration - dementia
somatic - glucose intolerance, reduced leptin/increased appetite, impaired immunity, increased risk of cardiovascualar disease adn cancer, death
different pattern of brain activity when you do tasks wen sleep deprived
how is sleep controlled after sleep loss *
reduced latency to sleep onset - faster to get to sleep
increase of slow wave sleep - NREM
increase of REM sleep - after selective REM sleep deprivation
what are the functions of sleep *
restoration and recovery - but active people dont sleep more
energy conservation - 10% drop in basal metabolic rate, but same as just lying still
predator avoidance - but why is sleep so complex
memory consolidation
what are dreams *
can occur in REM or NREM - more likely in REM
more recalled in REM
more emotional than real life - more limbic system than frontal lobe - idea of self, emotional regulation
lucid dream - know in a dream but continue to dream
what are the functions of dreams *
safety valve for antisocial emotions
disposal of unwanted memories
memory consolidation
or SE of way the brain functions in day - not functional
what is insomnia *
high prevalence
most cases transient
have functional impact on life - ie start to sleep in day
usually from lifestyle - rare to see chronic causes
causes of chronic cases - physiological eg sleep apnoea/chronic pain, brain dysfucntion eg depression/fatal familial insomnia/nighht working
treatment - sleep hygiene, hypnotics (most enhance GABAergic circuits), sleep cognitive behavioural therapy
how can you improve sleep disturbance
sleep hygiene:
establish fixed time for bed/waking
creating relaxing bedtime routine
only go to bed when feel tired - dont work on bed
maintain comfortable sleeping environment
not napping
avoid caffiene, nicotine and alcohol late at night
avoid hheavy meal late at night
dont use back lit devices before bed
what is hypersomnia *
excessive daytime sleepiness
secondary causes of hypersomnia *
obstructive sleep apnoea - because normal sleep cycle disturbed
restless leg syndrome and periodic limb movements of sleep
nocternal pain - diabetic neuropathy/arthritis
neurodegenerative disease - parkinsonism
medication - hypnotic misuse
env factors - noise
anxiety
rare - oesophageal acid reflux, severe bruxism
primary causes of hypersomnia *
narcolepsy
idiopathic hypersomnolence
post-TBI
describe the epworrth sleepiness scale
pt rate item from 0-never dose to 3 - high chance, higher score = more sleepiness
- sitting and reading
- watching TV
- sitting in interactive public space - theatre or meeting
- lying down to rest in afternoon
- sitting and talking to someone
- sitting quietly after lunch w/o alcohol
- sitting in car while stopped for a few min in traffic
what is narcolepsy *
falling asleep during the day repeatedly, and disturbed sleep at night
cataplexy - sudden, brief loss of vol muscle tone, often triggered by stong emotions eg laughter
dysfunction of control of REM sleep
orexin/hypocretin deficiency
how can shift work affect sleep
night work causes physiological processes to become desynchronised
this can lead to sleep disorders, fatigue and an increased risk of obesity, diabetes and cancer
describe sleep and neurological disease *
sleep disturbance can cause neurological disease, or other way
abnormalities in sleep before neurological disorder - eg REM behavioural disorder - cause of lewy body dementia/early manifestation
