Hi John,

It depends on how you sample from the volume to the surface, but yes, in general voxels in the white matter (and deep gray matter and csf and bone, etc….) won’t show up on the surface

Cheers Bruce

From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu On Behalf Of John Gelburg Sent: Friday, May 7, 2021 4:45 PM To: freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] How white matter voxel is represented on the surface ?

External Email - Use Caution Dear list,

I am sorry for a newbie question: Suppose I analyze the fMRI data in a volumetric way using SPM. I have a voxel that appears in a white matter. Does this mean that this voxel will not appear on the surface? In other words, there would be no corresponding vertex for my voxel ?

I would also appreciate any reading suggestions.

Thank you, John