I have scanned the position of the EEG electrodes for each one of my participants but when implement the montage, I see that my electrodes are shifted to the front of the head model. I do not have the MRI of my participants. I have tried using a scaling factor of the position of my electrodes and changing the size of the head outline but without success. I haven’t been able to shift the electrodes to be in the correct position. Is there a way to fix this? I have input the position of the electrodes and also the fiducial points when implementing the montage in mne. I’m attaching the figure of the electrodes positions.
What did you actually input in MNE? Values raw from your measurement device? Your measurement device likely measured the position of the fiducials and of the electrodes in a given coordinate frame and in a given unit. Now, it’s up to you to transform those 3D positions from the coordinate frame of the measurement device to the head coordinate frame, defined by the fiducials.
I have transformed all my coordinates to m and I thought that by using mne.channels.make_dig_montage and imputing my coordinates and my lpa,rpa and nasion I wouldn’t need to transform my positions. If I do the transformation you were mentioning, when using mne.channels.make_dig_montage would I still need to input the fiducials?
That’s a good point, maybe it should have done the transformation itself especially as I see a coord_frame argument defaulting to unknown for the native digitizer space… Let’s see what others have to say.
