Lesson 6- Cranial Nerves and the EEG Flashcards
(21 cards)
EEG activity is monitored continuously to determine:
sleep onset, sleep stages, and EEG abnormalities.
EEG signals results from local potentials generated on what?
pyramidal cell soma and dendrites
what cells cells are arranged so that their pyramidal cell bodies and apical dendrites lie in a specific orientation to the cortical surface.
cortical (brain cells)
The what is generated by changes in the electrical charge occurring in the membrane of these nerve cells.
The EEG
The neurons have what kind of potential that is (voltage) of 50-100 uV (microvolt 1/1,000,000) and are negatively charged on the inside (relative to the outside of the membrane)?
resting potential
Impulses arriving from what cause neurotransmitter chemicals to be released.
other neurons
what can cause an increase in membrane permeability?
neurotransmitters
As ions cross the more permeable membrane, they create a local change in the resting potential, termed..?
a postsynaptic potential(PSP)
The PSP (postsynaptic potential) can be considered either
EPSP or IPSP
The summation of these electrical potential changes among small groups of neurons closely packed in the cortex penetrates the meningeal coverings, spinal fluid and skull, and causes different portions of the scalp to be at different what?
potential levels
These differences are typically between 10 and 100 uV, and can be measured
by placing electrodes at different sites along the scalp
Depending on the reference, two types of EEG recordings can be obtained:
referential (monopolar) and bipolar.
In this type of recording- one electrode is placed above the cortical surface, and the other is placed at a distant, relatively (electrically) silent location.
In a referential recording,
The mastoid bone behind the ear serves well for what type of recording?
referential recording
In what type of recording do both electrodes place on the scalp over the cortical surface?
bipolar recordings
a collection of electrode derivations used for recording a specific biophysical signal
montage
Routine polysomnography should include a minimum of three EEG channels recorded from which regions of the brain?
the frontal, central and occipital regions of the brain.
what are the frontal electrode derivations?
F3-M1 & F4-M2
What are the reference electrode derivations?
C4-M1 & C3-M2
The third EEG channel, an occipital placement (O1 or O2) is used for the identification of what wave activity?
alpha waves
The recommended minimum EEG electrode placement consists of four scalp electrodes, what are they?
a ground electrode, and M1 and M2 mastoid reference electrodes.
