I recently noticed that some of my subject's spherical surfaces appears to have several small, pyramid-like points on them. One example is shown here in tksurfer:
http://fmrif.nimh.nih.gov/~adamt/sphere.jpg
Looking at these points in more detail in suma shows that several triangles are folder on top of each other so that all the vertices are on the spheres surface, but some triangles are entirely overlapped by others.
The spherical surface is here:
http://fmrif.nimh.nih.gov/~adamt/rh.sphere.asc (11MB)
And this is a close up of near node 141619 in suma:
http://fmrif.nimh.nih.gov/~adamt/sphere_suma_zoom.jpg
These distortions are causing us problems with subject averaging. Is there something we can do to fix or avoid them?
Thanks, -Adam
--- Adam Thomas adamt@nih.gov Functional MRI Facility, NIMH/NIH/DHHS 10 Center Dr, Room B1D708A Bethesda MD. 20892-1148 Phone:301-402-6351 Fax: 301-402-1370