Dear FreeSurfer Team,

I have questions about the sulcal depth.

1) I heard that the output/surf/?h.sulc is showing the sulcal depth.
  Is it correct that the sulcal depth measure unit is normalized z-score, mm? And is it correct that the (-) values of sulcal depth mean gyral region (green), and (+) values mean sulcal region (red)?

2) I wonder if ?h.sulc is based on white matter surface or pial matter surface.

3) I analyzed the sulcal depth by vertex-level. if the results include the sulc (-) values region, Is it meaning that the gyral height?

4) I wonder the method/commands for extracting the sulc value by label-level.

5) Could you let me know the recommended smoothing option if it possible?  (e.g. --fwhm-trg [N])

I appreciate your help.

Thank you.

Han Byul Cho