[Eeglablist] CSD maps.

[Arnaud Delorme]

The function del2map in EEGLAB computes the 2-D laplacian (CSD) of a 
scalp map. To image the laplacian of the first ICA component of an 
eeglab dataset

Th = cell2mat({ EEG.chanlocs.theta })*pi/180;
Rd = cell2mat({ EEG.chanlocs.radius });
[x y] = pol2cart(Th, Rd);
figure; topoplot(del2map(EEG.icawinv(:,1), x+j*y), EEG.chanlocs);

Arno

ps: I modified del2map so, in future EEGLAB releases, you will be able 
to type directly

figure; topoplot(del2map(EEG.icawinv(:,1),EEG.chanlocs), EEG.chanlocs);

Christopher Summerfield wrote:

>hi Arno,
>
>looking at the code for topoplot() and headplot() it seems that there's no
>option to plot a CSD (current source density) map.  I guess that what's
>involved is taking the 2nd
>derivative across the interpolated scalp data...in 2 dimensions?  do you
>have code to do this, or can you suggest how I might do it?
>thanks
>chris
>
>
>Christopher Summerfield
>summerfd at psych.columbia.edu
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-- 

*Arnaud Delorme, Ph.D.*
Computational Neurobiology Lab, Salk Institute
10010 North Torrey Pines Road
La Jolla, CA 92037 USA

*Tel* : /(+1)-858-458-1927 ext 15/
*Fax* : /(+1)-858-458-1847/
*Web page *: www.sccn.ucsd.edu/~arno <http://www.sccn.ucsd.edu/%7Earno>

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