afni.nimh.nih.gov

Hi-

In your '-netrois FILE', each ROI is defined as a set of voxels with the same integer value. "Target ROIs", through which targets pass, have integer values >0. "Exclusion zones" (or anti-ROIs, through which tracts cannot pass) have values <0. So, any voxels/regions that you want to exclude tracts from running, you can give a negative value (could be any negative value; I typically use '-1' for simplicity).

--pt