"mri_vol2surf    --mov     spmT_funcmap.nii     --ref     subj01/mri/orig.mgz.   --reg    tk.dat    --hemi rh   --o    flodername" 

in which, I got the registration file (tk.dat) by aligning my functional mean image to the orig.mgz in tkregisterfv. 

now the problem is when I overlay the activation map on the inflated surface, I can only see the voxels with positive t-values. I can't see the negative ones. I cannot change the threshold values provided by "configure overlay" to negative values. Also, changing the "z-score" option next to the overlay configuration doesn't make any difference. can you help me with this, please? 

Thanks a lot,

Atena