[Eeglablist] Questions regarding the pipeline of data processing.

[Simon-Shlomo Poil]

Dear Yohan,

Try to check out this page
http://www.nbtwiki.net/doku.php?id=tutorial:clean_data#.UWQFDMp8OqY it
might give you some ideas for how to proceed.

You may also just want to use semi-automatic methods
http://www.nbtwiki.net/doku.php?id=tutorial:automatic_and_semi-automatic_methods_for_eeg_pre-processing#.UWQFU8p8OqY

Best regards and good luck,
Simon

2013/4/9 Boillat Yohan <yohan.boillat at epfl.ch>:
> Dear all,
>
> I am new to the EEG technique and I have several questions concerning the procedure for the data processing part.
> The data are recorded with a SynAmps2 64 Channel  Quik-Cap. The sampling rate is 1000Hz.
> This is an ERP study with an interest in both early and late components.
>
> I plan to do the following steps:
>
> 1. I remove the bad electrodes (one or two max.).
> 2. I re-reference the data to the average..
> 3. I apply a high-pass filter of 0.1Hz  (IIR Butterworth, Order 2, ERPLAB).
> 4. I apply a low-pass filter of 45Hz  (IIR Butterworth, Order 2, ERPLAB).
> 5. I epoch the data according to the stimulus onset (-1000ms to 1000ms) and I use the whole epoch as a baseline.
>     as suggested by Groppe et al. (2009).
> 6. I reject epochs with gross artifact in order to have around 10% discarded (Delorme et al. 2007).
> 7. I run the ICA (runica, extended).
> 8. I use ADJUST (Mognon et al. 2010) in order to identify the components related to eye artifacts and then I remove them.
> 9. Spline interpolation for the electrodes previously removed.
> 9. Finally, the epochs are baseline corrected with a pre-stimulus period of 400ms and then averaged according to the different conditions
>
> So, my questions are:
>
> 1.Which criteria should I use to detect bad electrodes? I do not feel very happy with the pop_rejchan() function provided by EEGLAB as
> even by playing with the threshold it was not able to detect a channel that was obviously very bad.
> 2. Can I re-reference to the average if one or two electrodes were removed?
> 3. Is it correct to do the spline interpolation after the ICA?
> 4. Does it make sense to do a second baseline correction after the ICA, but this time with a pre-stimulus period?
>
>
> If you have more general comments about this procedure, they are more than welcome.
>
> Thanks a lot!
>
> Yohan Boillat
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-- 
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Simon-Shlomo Poil

Center of MR-Research
University Children’s Hospital Zurich

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Webpage: http://www.poil.dk/s/ and http://www.nbtwiki.net and
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