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

[marcocrocenzi at interfree.it]

>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?
>
>And one more question-which mathematical method is used in EEGLAb to draw ERP 
>surface plots? Is there any function to calculate Laplacians?
>
>Thanks in advance,
>
>Aleksandra Vuckovic


Dear Alexandra, 
your procedure is methodolologically uncorrect. The results of the ICA, the components and the weight matrix, are always differents if you change datasets, because all the dataset are different, and the ICA works whith this data.
Probably, you didn't see difference  because the datasets are very similar, and the final error, in this analysis, is small.

Best regards

Marco Crocenzi 
>
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