[Eeglablist] get global field power of ERP data

[Stefan Debener]

Dear Ki-Young,

if you have an epoched EEGLAB dataset, you get the GFP from using the ML 
std() of the averaged signal:

if length(size(EEG.data))==3
    gfp = std(mean(EEG.data,3));
end

An informative plot that may help you with the definition of ERP latency 
windows could look like this:

figure;
plot(EEG.times, mean(EEG.data,3), 'k');
hold on;
plot(EEG.times, std(mean(EEG.data,3)), 'r', 'linewidth', 3);

I find it sometimes useful to look at the GFP of the single-trials as well.
Best,
Stefan



Jung Ki-Young wrote:
>
> Dear all
>
> Perhaps, global field power is helpful to identify overall ERP 
> component from multichannel data.
>
> I wonder if I get global field power of ERP dataset from EEGLAB or 
> Matlab command line.
>
> Any comment or suggestion will be welcome!
>
> Thank you in advance.
>
>  
>
> Ki-Young Jung
>
>  
>
> ---------------------------------------------------------------------------
>
> Jung, Ki-Young, M.D., Ph.D., Associate Professor
>
> Department of Neurology, Korea University Medical Center,
>
> Korea University College of Medicine
>
> ---------------------------------------------------------------------------
>
>  
>
> ------------------------------------------------------------------------
>
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