Neurophysiology Flashcards
Normal sleep latency in adults
15-20 minutes
Which stages of sleep are slow wave?
3 and 4 (slow delta waves predominate in those stages)
When is there a nocturnal surge of growth hormone?
Stage 3 and 4 of NREM sleep
What inhibits growth hormone?
Somatostatin
When is the normal dominant alpha rhythm achieved?
12-14 years
Where is the dominant alpha rhythm seen?
Posteriorly in the occipito-parietal region
What can abolish the dominant alpha rhythm?
Opening eyes
Concentrating
Arousal state
Anxiety
Ongoing ___ rhythm is almost always abnormal in adults
Delta
What happens to EEG after ECT?
EEG immediately shows delta and theta excess but then returns to normal levels after 3 months of the end of treatment
What changes to receptors happens after ECT?
Reduced beta receptors
EEG changes in Angelman syndrome
Noted by age of 2 - prolonged runs of high amplitude 2-3Hz frontal activity
What does EEG of patient with absence seizures show?
Regular 3Hz complexes
Sleep changes with benzo on EEG
- Decreased sleep latency
- Increased sleep time
- Reduced stage 1 sleep
- Increased stage 2 sleep
What happens to melatonin during REM sleep?
Decreases
Which ion is freely permeable across cell membranes?
Chloride
Alpha wave frequency
8-13Hz
Beta wave frequency
13-40Hz
Theta wave frequency
4-8Hz
Delta wave frequency
Less than 4Hz
What is the dominant rhythm of infants on EEG?
3Hz - dominant delta and theta waves
Which stimulant does not cause REM rebound?
Modafinil
EEG finding in CJD
Generalised 1-2Hz bi or triphasic sharp and slow-wave complexes
(Earliest EEG finding is more often rhythmic generalised slowing)
EEG hepatic encephalopathy
Triphasic wave
Which stage of sleep do you see K-complexes in?
Stage 2
EEG finding in antipsychotics
Slowing of beta activity
Increase in alpha, theta and delta
Which sleep phase dominates in neonate?
REM
Orexin neurons are dysfunctional in which disorder?
Narcolepsy
EEG in sub acute sclerosing panencephalitis
High amplitude, repetitive bilaterally synchornic symmetrical polyphasic sharp wave and slow wave complexes which occur every 4 to 15 seconds
Which area of the brain when stimulated via magnetic pulse reduces depression?
Left prefrontal
What % of people with epilepsy will have normal EEG between attacks?
30-50%
Stimulation of which receptor leads to sleep onset?
Cholinergic receptors
Which wave is prominent when eyes are closed but patient is not sleeping?
Alpha
What effect do antidepressants have on EEG?
Slow beta
Increase theta and delta
EEG in generalised seizures
Generalised spike-wave discharges
Which condition is associated with low cortisol?
PTSD
Where is the highest concentration of serotonin found?
In the pineal gland
What is melatonin synthesised from?
Serotonin
How is melatonin synthesised from serotonin?
By serotonin-N-acetylase and 5 hydroxyindole-O-methyltransferase
Effect of propranolol on melatonin synthesis
Pineal gland regulated by beta-adrenergic mechanism - beta-antagonists such as propranolol decrease melatonin synthesis
What hormone is increased at start of sleep?
Testosterone
Which hormones are increased during slow wave sleep?
GH and SST
Which hormone is decreased during slow wave sleep?
Cortisol
What is the sleep switch nucleus?
Ventrolateral preoptic nucleus
What does the ventrolateral preoptic nucleus do?
Induces sleep by putting brakes on arousal nuclei
What are REM-ON neurons?
Cholinergic
What are REM-OFF neurons?
Noradrenergic
Which sleep stage increases in anxiety?
Stage 1 (light sleep)
What causes early morning wakening in depression?
Increased REM sleep
What is a lambda wave?
Single occipital, triangular wave produced by visual scanning when awake e.g. reading
