afni.nimh.nih.gov

Hi, Neuro-

The parts preceding your SurfDist command seem correct.

Re. the SurfDist command:
+ "-i std.60.rh.pial.gii" does, indeed, specify the surface on which your node indices will be located.
+ why do you want "-Euclidian"? That would be the distance between the two points as a straight line *not* constrained to the surface. From previous questions, I would assume you want "-Graph" (or, just not putting either of these options, because "-Graph" is the default)?
+ the previous point probably relates to why nothing shows up with outputting a path, because you have not estimated distance along a path.

So, I ran (where "nodelist.1D" just contains "13020 14278", which I believe are your two node indices of interest):

SurfDist -i std.60.rh.pial.gii -input nodelist.1D -node_path_do PATH_DO

... which produced the following text output:

#Internodal distance along graph of surface std.60.rh.pial.gii
#A distance of -1 indicates an error of sorts.
#From   to     gDist.
 13020  14278  55.87

--> note how the distance along the surface is *longer* than the Euclidean distance, which makes sense-- dist_euclidean has to be less than or equal to the dist_alongsurf.

I could then view the PATH* as follows:

suma -onestate -i std.60.rh.pial.gii -sv MNI152_2009_SurfVol.nii &
DriveSuma -com viewer_cont -load_do PATH_DO.1D.do

Note: are you sure you want to use the pial surface for calculating distance? That is the "outer" GM boundary; it can be fine, but you have to choose whether you want the grey-white boundary, or the pial.

--pt