Hi, Jenna-
It wouldn’t surprise me if that paper’s coordinates were specified in LPI orientation. If there are meaningful names for each location, that might help verify that “left” has a negative x-value, for example. I wish more authors provided that useful nugget of information, though… These are the rules about the interpretation of the xyz coordinates:
-orient code = Specifies the coordinate order used by -xyz.
The code must be 3 letters, one each from the pairs
{R,L} {A,P} {I,S}. The first letter gives the
orientation of the x-axis, the second the orientation
of the y-axis, the third the z-axis:
R = right-to-left L = left-to-right
A = anterior-to-posterior P = posterior-to-anterior
I = inferior-to-superior S = superior-to-inferior
If -orient isn't used, then the coordinate order of the
-master dataset is used to interpret (x,y,z) inputs.
I think I might still use “-orient LPI” explicitly, for stability, in case someone adapts your script elsewhere with a different template, or something.
The file you provide can have more than one row, which is what I would use, rather than many text files or many calls to the program.
I have never heard of that atlas, so I don’t really know what space it is in—it is slightly unclear to me what the final space is, but it is probably/hopefully the MNI152 space? The AFNI @SSwarper MNI template, MNI152_2009_template_SSW.nii.gz, is in MNI-152 space.
I believe the point of that paragraph is that users should make spheres around the specified locations on whatever grid they are using, to avoid having to regrid. Note that the output “spheres” may not look perfectly spherical or symmetric, because I might guess that the locations won’t sit exactly at the centroid of a voxel. So yes, using 3dUndump with those locations is likely the best/only want to go.
I guess many questions will be empirically by making the spheres, and visually verifying that they ~fill the brain template space. Hopefully ROI names can also verify the orientation information.
–pt