EEG

Question 1

When many synchronistically firing neurons create an EEG field, these can be approximated by a __________; these are defined by location and a vector representing the strength and location of the current’s flow.

Answer 1

Dipole

Question 2

How much synchrony occurs in a low voltage profile?

Answer 2

Very little

Question 3

Which brainwave does not have a generator?

Answer 3

Gamma

Question 4

Local resonant loops are characterized by _______ frequency brainwaves.

Answer 4

HIgh (above 30 Hz) - beta and gamma

Question 5

Regional resonant loops are characterized by ___________ and __________ waves.

Answer 5

Alpha, low beta

Question 6

Global resonant loops involve communication between distant sites of the cortex and involve ______ and ______ waves.

Answer 6

Theta and delta

Question 7

Connectivity in an EEG is measured by _______, _______, and ___________.

Answer 7

Coherence, phase, and cross-frequency coupling

Question 8

What is coherence?

Answer 8

The stability of the phase relationship. It is measured by the difference between two signals measured on the scalp.

Question 9

The best way to measure coherence is without a ____________.

Answer 9

Reference

Question 10

A blue phase lag indicates ….

Answer 10

Not enough lag time between brainwaves; likely from a hypercoherent brain.

Question 11

A red phase leg indicates …

Answer 11

Too much lag time; likely from a hypocoherent brain.

Question 12

The EEG is a _______-dimensional projection of _____-dimensional reality.

Answer 12

2, 3

Question 13

What is the inverse problem?

Answer 13

When we can’t determine the exact location of the EEG generator based on the scalp alone.

Question 14

A visible EEG requires at least _______ neurons in a cortical area of 6 square cm.

Answer 14

108

Question 15

Which part of the brain is the chief subcortical EEG rhythm generator?

Answer 15

Dorsal thalamus

Question 16

EEG amplifiers _________ the voltage between one site and the ground, and ________ any common voltage.

Answer 16

amplify, suppress

Question 17

EEG activity that is common to both electrode channels is called _________________.

Answer 17

Common mode rejection

Question 18

What is the interference to the electrical flow of brainwaves called?

Answer 18

Impedence

Question 19

The higher the impedence, the ___________ the amplitude of the EEG signal.

Answer 19

smaller

Question 20

Good impedence should be less than _______ kohms.

Answer 20

15

Question 21

The solution to the inverse problem is the ________ problem, which simulates the field distribution of a dipole using the Maxwell equation.

Answer 21

Forward

Question 22

What are two examples of inverse methods that are based on the forward problem?

Answer 22

Loreta and ICA

Question 23

The basis for source detection in the EEG and MEG is ________________.

Answer 23

Volume conduction

Question 24

All brainwaves are made up of __________ current.

Answer 24

Alternating; most amps are AC

Question 25

__________ current means the current flows in one direction, like with a power line.

Answer 25

Direct

Question 26

_______ amplifiers amplify the whole signal (both AC and DC)

Answer 26

DC

Question 27

Which amplifiers create the most noise?

Answer 27

DC

Question 28

In the MCN system, T3 is now _________.

Answer 28

T7

Question 29

In the MCN system, T4 is now _________.

Answer 29

T8

Question 30

In the MCN system, T5 is now _________.

Answer 30

P7

Question 31

In the MCN system, T6 is now _________.

Answer 31

P*

Question 32

EEG is the sum of the __________ representing pyramidal cells in the cortex at the scalp.

Answer 32

dipoles

Question 33

If all the lines on the EEG look the same, what is the most likely reason?

Answer 33

A contaminated reference/shared variance/common mode rejection

Question 34

What is the best montage to see where a problem is localized?

Answer 34

Average, or Laplacian

Question 35

Where is jaw tension most likely to show up on an EEG recording?

Answer 35

Temporal lobes, or F7F8

Question 36

If there is a subharmonic between Fz and Afz (28 Hz or 16Hz), one possible cause is a ___________

Answer 36

saltbridge

Question 37

The sensitivity of the recording is referred to as _______, and is measured in _____________.

Answer 37

Gain, mv

Question 38

__________ are designed to delete noise from the EEG, like a power line.

Answer 38

Notch filter

Question 39

What filter passes and rejects frequencies within a certain range?

Answer 39

Bandpass filter

Question 40

Which montage is best to assess global findings?

Answer 40

Monopolar, linked ears

Question 41

What montage is good for focal findings?

Answer 41

Bipolar, Laplacian

Question 42

________ is an inhibitory brainwave, while _____ and _____ are activating brainwaves.

Answer 42

Alpha. delta and theta

Question 43

A _____ is a transient that is 20-70 milliseconds long.

Answer 43

spike

Question 44

Which pattern indicates a possible seizure?

Answer 44

Spike and wave

Question 45

A _____ is a transient with a pointed peak that is 70-200 milliseconds long.

Answer 45

sharp

Question 46

When eyes are open, what brainwave should be attenuated?

Answer 46

Alpha

Question 47

Normal voltage of a brainwave should be around _____ microvolts.

Answer 47

40-50

Question 48

Low and high cut filters should range from ___ to ____ in a normal EEG.

Answer 48

1 Hz - 70 Hz

Question 49

What brainwave should be blocked with eyes open?

Answer 49

Lambda