[Eeglablist] Applying ICA weigthing matrix from one set to another

[arno]

Vuckovic, Aleksandra wrote:
> Hello,
>
> I am doing an experiment in which subjects have to repeat the same tasks
> several times and in several sets. All sets are obtained on the same
> day, in 30-45 min intervals and last 12-15 min each. 
>
>
> I would like to know if it is correct to calculate ICA weighting matrix
> for one set and apply it on the other sets for finding ICA components. I
> am using it for removing EOG artefact (thanks to all of you who helped
> me about that). Visually I see no special difference when I remove EOG
> using weighting matrix of that set or the other one but still would like
> to know if that is methodologically correct?
>   
Yes, this is correct since the data was recorded on the same day. The 
best approach though is to concatenate all datasets and run ICA (as ICA 
is more stable with more data).
> And one more question-which mathematical method is used in EEGLAb to
> draw ERP surface plots? Is there any function to calculate Laplacians?
>   
The surface plots use the function topoplot(). Yes, there is a laplacian 
function which is called del2map.

Best,

Arno