I see one can use the whole brain volume as the source space, but is it possible to use fMRI grid as the source location? And how do I set up that?
Thank you!
You mean a mask of activated voxels observed in fMRI?
The problem is that if you set the source space as your region of interest, all the EEG activity will be explained by this region, regardless of whether there is actual activity or not.
What you could do is estimate the sources and then load your fMRI mask as a volume scout.