[Mne_analysis] Beginner Question: epoching with subset of channels after average re-reference

[Ghislain d'Entremont]

Hi all,

I just started using MNE to analyze some EEG data I collected for a study I
am conducting. So far, I've been enjoying learning about the package. The
tutorials online are great. However, I seem to be stuck on something I can
only imagine is straightforward. First, an overview of what I am trying to
accomplish:

I use a 64-electrode cap.

Ultimately, I want to (1) re-reference to the average of all electrodes,
(2) apply some basic filters (3) look ERPs of 4 channels for various target
types.

I get stuck getting epochs (3). When trying to select one channel to epoch,
I get the warning message telling me that I should not apply a projector to
1/64 of channels...

How do I get around this given that I want to both re-reference to the
average of *all *electrodes and only do analysis on some subset of
channels.

I imagine that it is clear that I am confused, so any conceptual tips with
respect to the implementation of this package will be helpful.

I've attached the script I have been using. The last line of that script is
where I get stuck (as the comments will show).

Any help will be greatly appreciated.

Thank you,

*Ghislain d'Entremont*
BSc, Neuroscience, Honors
Dalhousie University
tel: 902-802-5671 (text)
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