[Mne_analysis] Computer forward solution using epoch.info rather than raw.info

FAIRS Amie amie.FAIRS at univ-amu.fr
Tue Jul 21 04:56:30 EDT 2020
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Hi everyone,

This is a naive question but I’d appreciate some clarity from someone who understands in more depth.

I’m currently running source recon MEG data using individual MRIs. I found that when running make_inverse_operator(raw.info, fwd, noise_cov) I was getting an error saying ‘no channels match the selection’. I checked in raw.info and no channels were marked as bad, so I tried again using epoch.info (also no bad channels) instead of raw.info and got the same error.

I have diagnosed this further up the pipeline – I was making the forward solution with:
make_forward_solution(raw.info, trans, src, bem, meg=True, eeg=False)
Thinking that this would pick only the MEG channels. However, my noise covariance is calculated from epochs, not the raw data, and I think that creating a forward solution using raw.info and the covariance using epoch.info resulted in a clash of channels, even though both of them have 270 MEG channels.

To get around this, I am now making the forward solution and inverse operator using epoch.info:
make_forward_solution(epoch.info, trans, src, bem, meg=True, eeg=False)
make_inverse_operator(epoch.info, fwd, noise_cov)

However, the tutorials always use raw.info. So my question is: am I introducing errors into the analysis calculating the forward solution and the inverse operator using epoch.info rather than raw.info? I think that only the channel names/placement are used from .info but I am not sure. In case relevant: I think that some of my channels in the epochs object were repaired/interpolated using autoReject.

Any clarity anyone can give would be appreciated so I don’t introduce errors.



P.S. thanks for updating the installation instructions – I followed them exactly and now have everything working on my virtual machine 😊

Dr. Amie Fairs
Aix-Marseille Université
Laboratoire Parole et Langage (LPL) | CNRS UMR 7309 | 5 Avenue Pasteur | 13100 Aix-en-Provence
Email : amie.fairs at univ-amu.fr<mailto:amie.fairs at univ-amu.fr>

While I may send this email outside of typical working hours, I have no expectation to receive an email outside of your typical hours.

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