Dear all,

 

I need to measure the distance between 2 points on the same hemisphere for subject A, in the common surface space as I have to compare it with the distance between other 2 points for subjects B, C...

I used

 

mris_pmake --subject A --hemi rh --surface0 sphere.reg --curv0 sulc --curv1 sulc --mpmOverlay euclidean --mpmProg pathFind --mpmArgs startVertex:1,endVertex:2

Questions:

1. Is the calculated path the geodesic, in this case spherical, measure that can be directly compared with that from another subject, or not?

2. How could I compare the distance on the pial surface  of subject 1 (vertex 1-vertex 2) to subject 2 (vertex 1 to2). Is changing --surface0 argument to pial enough? (In the Recon-all Dev table, sphere.reg is an imput to generating label/?h.aparc.annot, which in turn is used to generate ?h.pial surfaces, does that mean that pial surfaces from 2 subjects are already registered?)

3. I do not understand the choice of defaults for  --surface0 (inflated) ,  --surface1 (smoothwm), curve 0 and 1. This is not surprising, since I do not have the math expression for the cost function available; just wondering, what is the reason to have inlated as the default for surface 0? Do I need to change any of the auxilliary terms used above with sphere.reg to accomplish what I want to accomplish?

4. Last, is there a way to mark the vertices for these geodesic path on the main surface used in order to use then for label creation?

 

Your insight is very important,

thank you,

Octavian.