I am working on a functional probabilistic atlas. I find that some functional regions (particular along a big sulcus) show quite high probability value over a large sample, whereas the probability for some regions are quite lower. I think this disparity could be accounted for by the anatomical variation on each surface node that appears while surface-based registering individual surface to the average template that was provided by Freesurfer. For instance, the anatomical variation could be pretty small within a big sulcus (like central sulcus).

I assume that Freesurfer output a file which characterizes this type of anatomical variation. Could someone point me which file it is and how to use it to create a group-level measure in order to clear display somewhere has large variation. Thanks.

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Liang Wang, PhD
Neuroscience of Attention and Perception Laboratory
Princeton Neuroscience Institute
Princeton University
Princeton, NJ, 08540