[Eeglablist] Re-reference, import from BrainVision, rejection criteria

[Christine Michel]

Hi,
we just started using EEGLab and came across some questions I find no 
answer to in tutorials or the archive of this mailing list. So 
hopefully, you could help us. We are absolute newbies, so the answers 
may be quite easy but we just don't get there. We use the GUI.

We use BrainVision Recorder for recording EEG data and BrainVision 
Analyzer to analyse them. Now, we want to analyse our data with EEGLab.
We can easily import the *.vhdr data from BrainVision Analyzer to 
EEGLab, but we have problems with:

1. Re-reference the data: we record the data with the left mastoid as 
reference. We want to re-reference the data to the linked mastoids 
offline, but we want to keep the TP9 in our data. We tried Tools > 
Re-Reference > Re-reference data to channels "TP9", Retain old reference 
channels in data, exclude the eog channels.
As a resut, we have the TP9 left in the data, but its like a zero line. 
So data is not referenced to our implicit reference TP10 and TP9, but 
only to TP9?


2. We tried to import data, which we already re-referenced in 
BrainVision Analyzer, it didn't work. We exported the already 
re-referenced data from BrainVision, getting an *.vhdr data  as well, 
but we couldn't open it with EEGLab. Error message: "EEGLAB error on 
function pop_loadbva(): index exceeds matrix dimensions." Any ideas, why 
we cannot import this data?

3. we want to do an automatic artifact rejection. We want to try: mark a 
segment as bad, if there are changes more than 50/?V /in an intervall of 
200ms. We couldn't find this criteria in EEGLab. You have any ideas how 
to use this criteria?

I apologize if these questions are too easy, but we couldn't manage it 
on our own, so we hope  to find some support here. As you may have 
noticed, we are not used to work with EEGLAB, easy step-by-step answers 
would be appreciated. :-)

Thanks in advance,
Christine Michel



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