[Eeglablist] Questions regarding the pipeline of data processing.

[Boillat Yohan]

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