14
votes
Accepted
Why is Fast Fourier Transform applied to raw EEG data?
Fast-Fourier Transform (FFT) transforms a signal from the time domain into the frequency domain. Basically, any time-dependent signal can be broken down in a collection of sinusoids. In this way, ...
- 51.8k
7
votes
Accepted
What is "integrated spindle activity" in plain English?
Integrated spindle activity is just this paper's measure of the intensity of spindles. It isn't really a term of art, there is no defined thing "integrated spindle activity," it is just a description ...
- 40.1k
5
votes
Why is Fast Fourier Transform applied to raw EEG data?
Any periodic waveform can be produced by adding up a series of sin waves of the appropriate frequency and amplitude. The FFT looks at a complex waveform and calculates those frequencies and ...
- 193
5
votes
How can neuronal signals faithfully be reproduced by scalp electrodes?
EEG has been recorded beginning in the late 20s, by people who were fairly clueless about electricity. While the strength of the EEG is indeed weak, it is readily observable with even such ...
- 414
4
votes
Accepted
What physical or mental actions can be picked up by EEGs?
Many EEG responses are swamped in random brain activity, artifacts and background noise. A single movement typically doesn't evoke measurable activity, because its amplitude is so small with respect ...
- 51.8k
4
votes
Accepted
How can neuronal signals faithfully be reproduced by scalp electrodes?
Short answer
Small electrical EEG signals need to be amplified and noise-reduced to be detectable. Noise reduction techniques include mathematical averaging and signal processing techniques like ...
- 51.8k
4
votes
Accepted
Can multiple overt/covert intentions produce identical EEG readings?
To curtly answer your question: given the sheer amount of different thoughts possible (billions I guess) and the limited spatial resolution of the standard EEG as well as the restricted number of ...
- 51.8k
3
votes
What signal processors comprise an Event-Related Potential system for EEG?
Event-related potentials are an issue in many aspects of physiology, not just in EEG analysis, so this answer is more general.
The main problem is that electrical or other signals that are associated ...
- 710
3
votes
Accepted
Do repetitive movements on EEGs show up as discernible patterns?
Specific events, e.g. finger flexions, generate synchronized neuronal responses in the brain that can be measured on the scalp with EEG. However, a voltage response to a single event typically ...
- 51.8k
3
votes
Accepted
What are wave frequencies in the EEG?
EEGs are often analyzed in the frequency domain, where signals are subjected
to spectral analysis, typically by Fast Fourier Transformation, or FFT.
What an FFT basically does is decomposing a ...
- 51.8k
2
votes
Accepted
Heart rate sensor electrodes to be used for blink detection (simple EOG)
Despite initial difficulties, after inspecting the module really closely, I could successfully identify the (only) microchip on it, which is an Analog Devices IC, with all necessary functionality ...
2
votes
What is "integrated spindle activity" in plain English?
A pretty good approximation is to say that they are summing the activity of (rectified) spindle events, since we are talking about discrete signals.
And what is the meaning of "over time"?
This ...
- 1,188
2
votes
Brain wave and motor movement correlation
As said by MG_MD:
You would be thinking about moving, actually moving, and perceiving the movement. These affect different areas of the brain and as such, the electrical output would increase.
...
2
votes
Accepted
Efficacy of the 10-20 montage for EEG
The placement in terms of location on the scalp determines what region of the brain is sampled. The electrode density determines how many locations are sampled. The spatial resolution of an EEG has ...
- 51.8k
2
votes
Accepted
What's the proper term for "brain waves" read from an EEG?
The terminology around EEGs is variable, dependent on the context;
Brain wave is fine, but has a bit of a popular undertone;
Oscillation, as per the deleted answer, implicitly refers to a longer-...
- 51.8k
2
votes
Accepted
Understanding the configuration of channels in the 10-20 EEG montage
EEG 10-20 system. source: Wikipedia
How many actual channels are there?
21 in the figure, i.e., the number of active electrodes.
What's the difference between reference and active ...
- 51.8k
2
votes
What signal processors comprise an Event-Related Potential system for EEG?
ERPs are typically analyzed in terms of amplitude and latency. FFT is not really an option; it doesn't make sense. There may be some applications where it may be useful, but these are quite specific. ...
- 51.8k
1
vote
Accepted
Brain wave and motor movement correlation
EEG signals can be broadly analyzed in two domains; the time domain and the frequency domain.
EEGs are often analyzed in the frequency domain, where signals are subjected to spectral analysis, by ...
- 51.8k
1
vote
How does the frequency of a visual stimulus affect the steady-state visually evoked potential?
Short answer
SSVEP frequency corresponds to stimulus frequency and SSVEP amplitude decreases with stimulus frequency.
Background
The simplest form of steady state visual-evoked potentials (SSVEPs) ...
- 51.8k
Only top scored, non community-wiki answers of a minimum length are eligible