Thank you @tmedani
I am not sure I understand your answer, I am not projecting the sources to a common space yet, I am having trouble seeing subcortical sources at the individual subject level, despite using a grid in which there are vertices in that area. This is the tutorial I was following: https://neuroimage.usc.edu/brainstorm/Tutorials/CoregisterSubjects#Volume_source_models
Edit: upon close inspection, I can tell I have a value for each vertex in the volume grid if I open ImagingKernel variable in that subject. However, when I display the sources over the MRI only the cortical ones are displayed (have colors). How can I make it so that I see, for instance, the brainstem there as well?
Thanks again,
Fran