hello everyone

I have a question about statistics on LGI. for the LGI data, named as lh.pial_lgi, I used mris_preproc as following:

mris_preproc --fsgd fsgd.fsgd --cache-in pial_lgi --target fsaverage --hemi lh --out lh.pial_lgi

but freesurfer said

ERROR: format for lh.pial_lgi not recognized

so is there any method to solve this problem?

Thank you