[Eeglablist] Spread blinks and eye artifacts over IC

Tarik S Bel-Bahar tarikbelbahar at gmail.com
Mon Nov 13 11:44:35 PST 2017


Hello Mahsa,

You may want to use a 1 Hz bottom for your filter to get better ICA.

It's probably best to remove any components that are dominated by eye
blinks.

I would recommend just sticking with analysis of just the IC components
that are valid/neural, and ignoring/discounting the rest.

If you are rejecting IC components and rebuilding the eeg data: Some
researchers try to be extra cautious and they try not to remove ICs that
are "mixed", so as not to inadvertantly remove neural signal.

Note that ICA is not a perfect method, and that there are often ICs that
have both artifact and neural signal.

See Luca's reaching site to get info and training on selecting/reviewing
ICs, including a "practice" option that provides feedback about your
classification. At minimum, I recommend that students do about 200
classifications, review with an ICA-EEG expert, and then do another 200-300
classifications.

Remember that you also have to do cleaning before ICA, which does not seem
to be one of the steps you listed.
If you haven't had a chance to yet, please be sure to review the eeglab
tutorial steps, practice with with eeglab tutorial data, and check out
Makoto's pipeline suggestions.


If you haven't yet, you should check out the various ICA classification
plugins, such as MARA and SASICA, which should help you make a decision on
your ICs.









On Thu, Nov 9, 2017 at 3:54 PM, mahsa shalchy <mahsa.shalchy at gmail.com>
wrote:

> Dear Experts,
>
> I am trying to correct EEG data blinks and saccades using ICA, however, in
> some cases (i.e. when the subject is double blinking), ICA finds multiple
> eye related components.
>
> The problem is that except for the main blink component, other eye
> contaminated ICs, have neural information and I can not easily discard them
> ( please find an image of ICs here:
> https://www.dropbox.com/sh/qjz2v3ke6zdr1j1/AABoSzG4s6ZyAlUz_vYC8slsa?dl=0)
>
> I tried using PCA before ICA but it didn't seem to work.
>
> For the preprocessing I did the following steps before applying ICA:
> Resampling, Filtering (0.1-40), re-referencing to average
> mastoids,epoching.
>
> I highly appreciate your help on this problem.
>
> Many thanks,
> Mahsa
>
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to eeglablist-unsubscribe at sccn.uc
> sd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sccn.ucsd.edu/pipermail/eeglablist/attachments/20171113/df850e35/attachment-0001.html>


More information about the eeglablist mailing list