Hello,

We are trying to project a volume map onto a surface. Our network based volume map is a .vmp file and our surface is a nifti file. We were able to convert the volume maps from .vmp to nifti.
Our volume map is: negative_allsocial_proportion.nii
Our surface is: SN_like_cortical_lh.nii
The output file is named: neg_allsocial.nii

We are trying to use the following command to now project the volume map on surface and the issues we are facing are:
1) We are unsure of what the purpose of the registration file is and where in the mir_vol2surf command should we specify the surface 
2) If it is a matrix for something related to the surface on which we want to project our volume then how should we go about obtaining the registration file appropriate for our comparison.

Command:
mri_vol2surf --src negative_allsocial_proportion.nii --src_type analyze --srcreg [REGISTRATION MATRIX] --hemi lh --o ./neg_allsocial.nii --projfrac 0.5

Then to project it:
tksurfer fsaverage lh inflated -ov neg_allsocail.nii