NEUR533 - Brain rhythms and sleep Flashcards
LEARNING OUTCOMES
What is measured with an electroencephalogram (EEG)
- cerebral cortex general activity
- Diagnose sleep disorders/epilepsy/research
What does MEG stand for?
Magnetoencephalography (MEG)
Concerning EEG rhythms, what are beta HERTZ and behavioural states?
15 - 30 Hz - activated or attentive cortex
Concerning EEG rhythms, what are alpha HERTZ and behavioural states?
8 - 13Hz
- Quiet waking state
Concerning EEG rhythms, what are Theta HERTZ and behavioural states?
4 - 7 Hz
- Some sleep and waking states
Concerning EEG rhythms, what are Delta HERTZ and behavioural states?
Less than 4Hz
Deep sleep
High synchrony
High EEG amplitute
What’s the part of the brain to be associated with neuronal oscillations, and massive cortical input as a PACEMAKER?
THALAMUS - Nucelus reticularis thalami (NRT)
Regulated also by voltage-gated ion channels
- Hyperpolarization =
Review EEG on thalamus and cortical interaction
3 function brain sleeps
EEG RYTHMS DURING SLEEP STATES
- Hippocampus has a replay memory sorting and consolidation
- All memory is stored within the hippocampus via LTP
FOCUS ON THE DIFFUSE MODULATORY NEUROTRANSMITTER SYSTEMS - LEARN THEM PROPERLY
MORUZZI’S RESEARCH
learn key components of the waking/sleeping modulatory systems
- Not getting visual stimulation in sleep
- Having visual input from higher regions in the brain
- Visual information is not being accurately interpreted by the frontal cortex regions in sleep
REM ON - Cholinergics
REM OFF - Serotonergics
SLEEP PROMOTING FACTORS
Gene expression during sleeping and waking
- Has light sensitive ganglionic neurons in SCN
- Right above optic chiasm
- SCN (within the hypothalamus)
- Orchestrator of the circaidian rhythm
Clock genes
REtinal ganglion cells and SCN
What is the name of the clock genes regulated by the SCN?
Cryptochrome
WHICH BRAIN MECHANISMS MODULATE SLEEP?
- SCN of the hypothalamus
- Brain’s biological ‘clock genes’
- Light via retino-hypothalamic tracts
- Melatonin
- Orexins - neuropeptides produced in dorsal hypothalamus (control of appetite and arousal working as NT)
High frequency, low amplitude rhythms are associated with what?
Alertness and waking or the dreaming stages of sleep
Low-frequency, high-amplitude rhythms are associated with what?
Non-dreaming sleep states
Drugged states
Comas
If cortical neurons have high synchronicity - would this increase EEG amplitude? Y/N
Yes
What are the 2 thoughts about the generation of synchronous rhythms in EEG?
(1) They may all take their cues from a central clock, or pacemaker
or (2) they may share or distribute the timing function among themselves by mutually exciting or inhibiting one another.
What’s the difference between a partial and generalized seizure?
Generalised seizure: involves the entire cerebralcortex of both hemispheres
Partial seizure: involves a particular area of the cortex
In both cases, the neurons within the affected areas fire with a synchrony that never occurs during normal behavior. As a consequence, seizures are usually accompanied by very large EEG patterns.