[Eeglablist] interpolating electrode using topoplot

[arno]

You may use the attached script to perform interpolation of an 
electrode. The function uses a similar mechanism compared to topoplot 
for interpolation (it actually allows for a choice of 5 methods) but can 
interpolate whole time series. It is not spherical interpolation, just 
planar interpolation. Andreas Widmann has an EEGLAB plugin in 
development for spherical interpolation (below)

http://www.uni-leipzig.de/~biocog/widmann/eeglab-plugins/index.html

After you have performed interpolation on your dataset, you may use 
topoplot() as before. Note that it is not recommended to perform 
interpolation before running ICA. The attached function will take care 
of you ICA information when you perform interpolation.

Hope this helps,

Arno

Natasa Kovacevic wrote:
> I run into a problem when trying to interpolate values for one electrode
> using other electrodes based on the following the logic:
>
> eeg = original data set where time series for electrode Q needs to be
> replaced by interpolated values
>
> tmp_eeg = pop_select(eeg,'nochannel',Q); % remove bad electrode
>
> use topoplot on tmp_eeg with 'noplot' option to get interpolated value
> for coordinates corresponding to Q
>
> insert interpolated values back into eeg 
>
> - it reports 'out of bound' error for many values of Q. I believe that
> there is a bug in topoplot function when using 'noplot' option and it
> has to do with mapping of electrode coordinates (theta and radius) into
> the rectangular grid of interpolated values. 
>
> I believe that the following portion of topoplot.m  (starting at line
> ~1260)
>
>   

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