Hi everybody,

I am interested in doing sub-sampling of functional data for some new analyses. Just about the only reference I can find to sub-sampling of data in FreeSurfer is in mri_surf2surf, which has an optional flag trgicoorder. The comment for this flag is:

“This specifies the size of the icosahedron according to the formula #vertices=10*4^n+2. In general, it is best to use the largest size available.”

It would seem that I might be able to use this flag in order to sub-sample surface data by using a smaller n (it seems as if the default for fsaverage is 7 according to the specified formula). Is this correct?

Are there any particular guidelines to n? Other surfaces have a variety of vertices, so it seems that n does not have to be an integer?

If I computer a surface of functional data for a given subject with a specific ‘n’ and resulting nVertices, should I also calculate an according anatomical surface with the same number of vertices for display and analysis?

Thanks!

Joakim