Neurophysiology Flashcards
What is the general function of the following lobes
Frontal, Parietal, Occipital, Temporal
Frontal Lobe - problem solving/higher function
Parietal Lobe - Spatial perception
Occipital Lobe - Vision
Temporal Lobe - Language and Information processing
How many layers does the cerebral cortex have
6
What type of neurons generate the EEG
Pyramydal
What layers of the cortex are pyramidal neurons located, and what layer is their cell body location
Cell body located in layer 5 and project to layer 1
What orientation are pyramidal neurons
Vertical
What charge will a cell be if it has an EPSP
Negative
What is the resulting charge of the scalp surface and thus the deflection on the EEG going to look like if there is an EPSP near the cell body of the pyramidal neurons
EPSP arriving to the cell body will make that end of the neuron negatively charged. This makes the top of the neurons positively charged.
Positive discharge on EEG is a NEGATIVE (downward) deflection
What ions are usually responsible for postsynaptic potentials
Na+/Ca2+
How long are EPSP
50ms
What is an example of a neurotransmitter that causes EPSP
NMDA and AMPA
What is an example of a neurotransmitter that causes IPSP
GABA
What is the thalamus role in generating EEG
The neurons that excite the pyramidal neurons come from the thalamus. So is the thalamus isn’t working, then there will be no excitation of pyramidal neurons and no EEG created
Where are the pacemaker cells of neuronal intrinsic rhythm located
In the thalamus
What is paroxysmal depolarizing shifts and what does this cause in the morphology of the EEG
These are sustained EPSPs that generate epileptiform spikes
What 3 anatomical landmarks are located at the beginning of measuring a head for EEG
Nasion (bridge of nose)
Inion (bump at the back of skull)
Preauricular points (middle of ears)
What is the minimum and ideal impedance of EEG electrodes
Ideally <5kΩ, minimum <10 KΩ
What is the maximum impedance difference we can have between a pair of electrodes in EEG
<5kΩ
What is the effect on artefact is the impedance of the electrode is high
High artefact
When measuring the head in the sagittal plane, what is the value of the interval between each electrode
10% of total sagittal plane length between nasion and first electrode, and inion and first electrode.
20% interval between the rest of the electrodes
When measuring the head in the horizonal plane, what is the value of the interval between each electrode
10% of total sagittal plane length between nasion and first electrode, and inion and first electrode.
20% interval between the rest of the electrodes
What amplifier is used in EEG machinery
Differential amplifiers
What is the usual sensitvity control set at in EEG machines
7-10uV
What would be the consequence of having the amplitude sensitivity control too high
There would be a decreased sensitivity to the signal
What is the sweep speed of EEG
30mm/s