Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Psychology - CN > Lecture 5- EEG > Flashcards

Lecture 5- EEG Flashcards

1
Q

Who was EEG invented by?

A

Hans Berger (1873-1941)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

When was the first EEG result published?

A

1929

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What unit of electrical activity is measured?

A

Microvolts (millionth of a volt)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are ERPs?

A

measure of potential fluctuations time locked to an event

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the spectral content of EEG?

A

analyses the type of neural oscillations that can be observed in EEG signals in the frequency domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Advantages of EEG

A 
Cheaper
Portable
Very high temporal resolution (milliseconds)
Tolerant to movement 
Silent
Simple to conduct 
Can detect covert processing 
Can elucidate stages of processing rather than just the end result
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Disadvantages

A

Low spatial resolution
Poorly measures neural activity occuring below upper layers of brain
Time intensive
signal:noise is poor
Brain have many folds therefore opposite potentials across a sulcus can cancel out (MEG would still work because magnetic field is orthogonal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain volume conduction ?

A

Ions of a similar charge repel each other

When many ions are pushed out of many neurons at the same time, they push their neighbours and so on, in a wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does volume conduction influence the EEG signal?

A

When the wave reaches electrode, they push or pull on the electrons inside the metal

The difference in push/pull voltage between an electrode and a reference electrodes is measured by a voltmeter = EEG signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

EEG activity reflects the ____ of activity of many neurons with a similar ____ ____

A

synchronous

spatial orientation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why might ions from cells not line up and not create a detectable wave?

A

Because the cells have not have similar spatial orientation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What cells are thought to produce most EEG signal? Why?

A

Pyramidal neurons - they are well aligned and fire together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why is activity from deep sources difficult to detect?

A

Because voltage field gradients fall off with the square of the distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Synchronous activity of a large number of neurones can give rise to macroscopic _____

A

oscillations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is impedance measure in? How is it different resistance?

A

ohms

Has a phase component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How to reduce impedance?

A

Using conductive gel Wiggling electrodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What’s the recommended max level of impedance

A

below 5 kOhms is considered good

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the most common framework for setting up electrodes?

A

10-20 system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the elctrode in the top-middle of the head?

A

Cz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

the Nasion and Inion are equidistant to which electrode?

A

Cz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

High-pass filter fillters out ___ artifact. For example _____

A

Slow artifacts e.g. electrogalvanic signals and movement artifacts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Low-pass filter filters out ____ signals

A

electromyographic (signals from muscle movement)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is applied to remove artifacts caused by electrical power lines?

A

Notch filter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

EEG display can be set up in different ways to represent difference between voltage at 2 electrodes. These are different forms of _____.

A

Montage (e.g. sequential, referential, average reference, laplacian)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What kind of analysis can help remove artifacts (e.g. blink detection)?
Independent Componant Analysis (ICA)
26
How are ERPs analysed?
By averaging over many trials/sites
27
P100?
basic visual response (occipital)
28
N100
basic auditory response (frontal)
29
N170
reflects face stimuli
30
P300
reflects decision making
31
Lateralized Readiness Potential (LRP)
indicator of motor planning
32
What part of the ERP is analysed and quantified?
Peak amplitude Latency Area under deflection (And/Ors)
33
Multivariate Analysis in EEG adds what component?
Temporal
34
Fourier analysis is the principle that...
Any waveform can be broken down into or constructed from the sum of sine waves of different frequencies
35
Fourier analysis can tell you the separate ____ and at what _____ composed your waveform
frequencies | amplitudes
36
What is the Fourier Spectrum?
Plots amplitude as a function of frequency
37
What are the frequency bands found in EEG?
``` Delta <4Hz Theta 4-7Hz Alpha 7-14Hz Beta 15-30Hz Gamma >30Hz ```
38
Delta
<4Hz – sleep, some attention tasks
39
Theta
4-7Hz, similar to alpha
40
Alpha
7-14Hz - resting, tiredness, attentional lapses
41
Beta
15-30Hz - motor behaviour
42
Gamma
>30Hz - long range neural synchronisation
43
What is steady state?
Use an oscillating stimulus at a frequency that can then make the brain oscillate at that particular frequency. Measure the steady-state evoked potential - the amplitude at the stimulus frequency
44
Head and contour plots?
Plots the EEG signal across the scalp Typically show the distribution of activity across electrodes at specific point in time
45
The processes of inferring from the distribution of activity across electrodes where in the brain the signal originated is called...?
Source localization
46
Special equipment is required to combine EEG with MRI or MEG because....
Too much metal!
47
In regard to the N and P waves of the EEG, N and P stand for...
Positive and negative
48
An EEG waveform measures the change over time of the ____ between ____ ____ on the scalp
Voltage between two points on the scalp
49
A contour plot shows...
the distribution of activity across sensors at a specific point in time
50
If a large number of neurons are all firing at once, this will produce an ___ ____ and an accompanying ____ ___
Electrical dipole | Magnetic field
51
Nearby electrodes are often ___ ___ with each other
highly correlated
52
Opposite potentials across a ___ can cancel each other out
sulcus
53
In EEG we are measuring difference in electrical charge, this is called ___ or ____ _____
Voltage | Potential difference
54
In EEG there must always be a ____ electrode
reference
55
The voltages we measure are usually in the order of ___ of ____
tens of microvolts
56
A microvolt is a _____ of a volt
Millionth
57
Electrodes are typically made of?
Silver/silver chloride
58
What does a multimeter do?
Manually measures impedance
59
Because EEG signals are so small, we need to ___ them But what else will be ___? ____ also digitise the EEG signals
Amplify Noise Amplifiers
60
The true signal we are interested in can be revealed by?
averaging over multiple trials and/or multiple subjects AND/OR average over several electrodes to get a global signal for a particular region
61
Blinks show up on the _____ at the bottom of the plot
electro-oculogram (EOG)
62
The positive and negative components of a waveform are known as ______
deflections
63
Using steady-state, we can measure the neural response to some stimulus as a function of its ____
intensity
64
Clinical applications of EEG
``` Epilepsy Migraine Movement disorders (e.g. Parkinson’s) Psychiatric disorders Diagnosing brain death, coma etc ```
65
How can we relate EEG responses to subjective experience? What can be used to derive an underlying model that explains data from both measures?
Do psychophysical tasks whilst measuring EEG Computational modelling
66
Neurofeedback?
Way of monitoring your own internal mental state May or may not work
67
Frequency vs time plots
``` time = x frequency= y amplitude = colour ```

Psychology - CN (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions