[Eeglablist] unusual ICs

[Makoto Miyakoshi]

Dear Isaiah,

That's a subspace. You ran the second ICA after IC rejection, correct?
Actually, the second ICA is NOT after IC rejection. The results from the
1st ICA should be used for cleaning using icaact and not IC rejection. I
know it is a very tempting idea to run 1st ICA, reject ICs, then run the
2nd ICA to find new faces... but it never works because when you reject ICs
your forward-projected scalp EEG data are rand reduced.

See also 're-reference' part of the following wiki page
http://sccn.ucsd.edu/wiki/Makoto%27s_preprocessing_pipeline

Makoto

On Wed, May 20, 2015 at 5:59 PM, Isaiah Innis <isainnis at umail.iu.edu> wrote:

> Hello eeglab list:
>
> After running a 2nd ICA on a dataset we sometimes run into into strange
> ICs in the first few positions, usually ICs 1-5.
>
> Here is an example (images of IC1-4 for a single subject):
>
> https://www.dropbox.com/sh/zz9zt7qoa8coq85/AAD7J3FaEx7QWEe_ti9OuLxda?dl=0
>
> It looks like it might be the same thing in the "How to deal with
> 'corrupted' ICA decompositions section on the wiki but I don't know for
> sure. We do normally reduce our 64ch recordings to 32ICs using the 'pca'
> option.
>
>
> Does anyone have any experience with this? Is something wrong with our
> settings?
>
> Thank you,
>
> --
> Isaiah Innis
> Indiana University '13
> EEG Technician, IUB IRF
>
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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