[Mne_analysis] noise covariance matrix

[elena at nmr.mgh.harvard.edu]

Dear MNE specialists,

I am new to MNE and MEG and I am going to analyze coherence on the MEG
data that were originally supposed to be analyzed as averaged ERPs.  For
this purpose I need to analyze non-averaged (ongoing, spontaneous ) MEG.
Page 34 of the MNE manual says that in the case of ongoing MEG the noise
covariance matrix should be calculated based on the empty room
measurements.  Unfortunately, when the data were collected they were not
supposed to be analyzed as ongoing activity and the empty room
measurements were not done.
Can I still analyze coherence on this data? What kind of noise weighting
can be used in this case?

Elena