Hi Tuomas, when you sample the data onto the surface, you get a value for each vertex. The vertices are more closely spaced than the typical fMRI voxel, so each voxel will map to multiple vertices.

doug

Tuomas Tolvanen wrote:

Dear freesurfer experts,

I was wondering that what is the logic or technique how mri_vol2surf works? I mean that I have an spmT-image that contains T-values for voxels and I want to visualize these activations on a surface. The number of voxels with value > 3 is ~60. When I check the number of vertices with value > 3, it's ~250 (after mri_vol2surf). So how are the voxels projected to the surface (vertices)?

-Tuomas

---

Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer