[Eeglablist] Average power topographic maps

Arnaud Delorme arno at ucsd.edu
Mon Oct 31 20:57:14 PDT 2011


Hi Christian,

> 1)
> If anybody has an answer to the question raised a few weeks ago on this 
> list by Tracey, I would be happy to hear it, too: "I would like to ask 
> whether EEGLAB allows one to plot average power topographic maps in 
> standard frequency bands (delta, theta, alpha, beta, gamma). From the 
> 'Plot channel spectra and maps' command one can only plot spectral plots 
> for individual frequencies. Is there a way of taking the average over a 
> fixed band?"


Yes, this is possible when creating a STUDY. A STUDY can be created using a single subject.
Then you may use the parameter menu to specify a frequency band. You will only be able to plot one frequency band at a time though.


> 2)
> Is it possible to plot only the scalp maps of the 'Plot channel spectra 
> and maps' in 1-Hz-frequency steps ranging from 1 Hz to 20 Hz (that is 
> generate 20 scalp maps at once and in one figure)?


Sure, put "1:20" (without the quotes) in the "Frequency to plot" edit box


> 3) Is it somehow possible to get a plot like the lower one of 'Plot 
> channel spectra and maps' but just for certain electrodes to have a more 
> concise representation?


(1) You may click on any curve in this panel and it will indicate the index for each electrode on the Matlab prompt
(2) You may add the additional parameter " 'mapchans', 1:10 " to plot only the 10 first channels (for example)
(3) You may also use the channel property GUI to plot the spectrum of each electrode


> 4) A more general one: Does anybody know of an open collection of 
> EEGlab-(example)-scripts for doing time-frequency analysis in EEGlab 
> that goes beyond the few examples on the EEGlab website?


There is no such repository yet.
You can generate automatically scripts for yourself by using the graphic interface and then using the "eegh" command to retrieve the command history of whatever you have been doing on the graphic interface.

Arno




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