Flashcards in EEG (Okt 29 lecture) Deck (49)
What is Ohm's law?
Voltage(E) = Current(I) x Resistance(R)
How is current measured?
What is current a measure of?
The actual flow of electricity through a conductor
What letter represents current in Ohm's law:
E = I x R ?
Current is represented by I (Intensity)
How is voltage measured?
What is voltage a measure of?
Electromotive force (pressure that pushes the current through the conductor)--NOT a measure of flow of electricity
What letter represents voltage in Ohm's law:
E = I x R ?
Voltage is represented by E (Electromotive Force)
Which part of Ohm's law can be explained by a "water tank on the hill" analogy, where there is potential for water to flow, even if no water is actually flowing?
Voltage (E; Electromotive Force)
How is resistance measured?
What is resistance a measure of?
The ability of the substance to keep charged articles from passing
What letter represents resistance in Ohm's law:
E = I x R ?
Resistance is represented by R
What 3 factors influence resistance?
(1) composition of a substance (e.g. copper vs. zinc)
(2) its length
(3) its diameter
What is Impendance (Z)?
The resistance to the flow of alternating current (AC)
If a magnetic field passes through a conductor, it.....
induces an electrical current
(this is how devices can cause interference)
How is a neuronal dipole created?
Negativity at apical dendrites and positivity at the soma
Which cells are best for ERP recordings?
Pyramidal cortical cells
Which cells are most unlikely to be recorded with an ERP?
Cerebellar cells (bc highly folded surface may result in nearby cortical patches cancelling)
EEG is sensitive to....?
Excitatory & inhibitory postsynaptic potentials at apical dendrites (of massively synchronized cortical neurons
Is EEG sensitive to action potentials?
Increasing the number of trials also increases...
Signal-to-Noise Ratio (SNR)
Doubling the SNR _____ noise about 30%, but requires _____ times as many trials?
Reduces noise about 30%, but requires 4x as many trials!
What are the 3 types of electrodes used?
Active (A), Reference (R), & Ground (G)
What is the standard placement system for EEG?
The 10-20 System
Electrode Labeling: F stands for?
Electrode Labeling: C stands for?
Electrode Labeling: T stands for?
Electrode Labeling: P stands for?
Electrode Labeling: O stands for?
Electrode Labeling: Fp stands for?