Hi, Sondos-

I am afraid I don't understand. In my view, the number of tracts to/from/intersecting a target ROI is a single number. I'm not sure what a 'maximum number of tracts' would be?

One possible thing to clarify-- in other tracking programs, there is a paradigm of "starting tracts" from an ROI and letting them fire out elsewhere, seeing where they hit. As a consequence, there is inherent directionality of tractography-estimated connections (connections from target A to target B can be different htan connections from target B to target A). That is not the case in AFNI. Whole brain tracking occurs, and then the program finds tracts that have any segment intersecting an target ROI ("OR-logic" connections) as well as any tracts that have segments intersecting multiple taret ROIs ("AND-logic" connections), and those are kept and used.

I am not sure if that is a factor in our different terminologies?

--pt