EEG and sleep Flashcards
What is electroencephalogram?
recording of electrical activity on of brain scalp
Who invented electroencephalogram?
hans berger
What is good and bad about EEG?
poor spatial resolution bu good temporal resolution
What does MEG measure?
magnetic field evoked by current flow in brain
What do individuals show when eyes are closed nd they are in a relaxed state?
alpha rhythm
8-14Hz)(10-50microV
What rhythm do individuals show when eyes open/aroused?
beta rhythm
14-25Hz
What rhythm do awake nromal people show?
gamma rhythm (intermittent bursts of synchronous 30-80Hz)
Where is wave origin?
electrical activity in deep cortex (up to 6mm) and deeper signals are missed
cortico-thalamic oscilations
What region are a-rhythms found?
in visual cortex
What region are k(kappa) rhythms found?
in auditory cortex (are alpha like)
What region are micro rhythms found?
sensorimotor cotex (alpha like) (mirror neurons, autism???)
when are theta waves more common?
tumours
young children
during frustration
could be hippocampal rhythm memory
What can epilectic discharge cause on eeg?
spikes in EEG (after this is spreads thoughout brain )
what is REM sleep?
rapid eye movement sleep
What are the stages in non-REM sleep?
1- alpha rhythm slows
2-slowing and sleep spindles (light sleep)
3-slowing, no spindles
4-increase in amplitude but low frequency (deep sleep)
When in embryo do these stages occur ?
~24weeks
What could lack of sleep relate to?
cognitive impairment
When does REM occur?
it usually follows deep sleep (is dream sleep)
What is REM sleep rhythm ?
beta-like (as if awake)
How does dolphin sleep?
it cant- only half of brain sleeps at one time
What animals dream?
mammals and young birds
What neurotransmitter does REM on neuron use?
acetylcholine
What neurotransmtters does REM off sleep use?
noradrenaline and serotonin
What from the hypothalamus regulates sleep?
suprachiasmatic nuleus
What does suprachiasmatic nucleus secrete?
hypocretin and orexin
what causes narcolepsy?
Disturbances to orexin and hypocretin level
How does pineal gland regulate sleep?
sleep/wake cycle affected by melatonin from pineal.. (secretion of melatonin varies with light level)
releases serotonin in day
what is sleep probability a balance of?
Process S – sleep / energy debt
Process C – circadian rhythm (SCN)
what else apart from the hypothalamus regulates sleep?
cortex, basal forebrain and pineal gland
