Hello,
I would like to ask for some clarification regarding the use of patch
area information in the computation of forward solutions and inverse
operators.
In section 7.11.2 (MNE 2.6.), the leadfield is defined without area
information, and I assume "forward solution" and "gain matrix" are used
synonymously. In the context of mne_do_forward_solution, a
"current-density transformation" is mentioned, which requires patch
information. I therefore assume that MNE uses the patch information for
the inverse operator (not for the forward solution), in order to compute
current densities.
Therefore, if I use the forward solution (fwd.sol.data) to compute my
own inverse operator, I have to divide the estimate at each vertex
location by its patch area. Is this correct?
In order to obtain the patch area for a particular vertex, I first
select the vertices used in the forward model in fwd.src.vertno, then
find the patches that are closest to those in fwd.src.nearest, and
compute the area of a patch by summing across the corresponding vertex
areas from the w-file *p-patches*.w (w.data)?
I hope I'm at least heading in the right direction...
Regards,
Olaf