[Eeglablist] A second ICA after removing components?

[Maximilien Chaumon]

Hello all,

I'm currently cleaning data before working with components.

   - I cut my dataset into epochs
   - reject epochs where signal is bad
   - run an ICA
   - find blink and muscle components, reject them
   - run an ICA again, and look at my components.

... as I understood was suggested at the bottom of this page
http://sccn.ucsd.edu/wiki/Chapter_01:_Rejecting_Artifacts

Then the ICs look very nice but come in pairs of extremely similar
topographies with different time courses, as shown on this
picture<http://oszilla.hgs.hu-berlin.de/public/2ICAs.png>
.
I am wondering what happened here. I can imagine that rejecting components
before running the second ICA is what went wrong... But why did I read that
on the wiki?

Thanks a lot for any advice.
Max
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