Hi,

I am running Probtrackx using two ROIs (ROI_1, ROI_2) and I am interested in
the global connectivity between these two regions. So what I need is the global
number of fibers which start from ROI_1 and reach ROI_2 and the same in the
opposite direction (from ROI_2 to ROI_1). What I see in that there are two
different ways to proceed:

- Run probtrackx in multiple mask mode, using my two ROIs as masks;

- Run probtrackx in seed to target mode, using as seed ROI_1 and as target
ROI_2 and the same in the opposite direction (seed ROI_2 and target ROI_1).

These two methods give very different results. Could you suggest me what is
the best way to proceed?

Thank you in advance!