MEM and wMEM are based on a parcelization of the whole cortical surface, based on geodesic metric along the cortical surface. Therefore, an extension of MEM in a volume space is not straightforward, we are planning to implement a version of it but this will take some time, so not available for the moment. What can be done is extrapolating within the gray matter the recontruction done on the surface, this is the way we are usually providing results to our clinician colleagues. Hope this helps