I would like to extract the pial_lgi data from Freesurfer's V1.thresh labels but can't quite figure it out. I've tried adapting the commands from the LGI Freesurfer tutorial as such:

mri_segstats --label-thresh BV20 lh V1.thresh.label --i $SUBJECTS_DIR/BV20/surf/lh.pial_lgi --sum lh.V1.thresh.label.stats

I've also tried 

mris_anatomical_stats -l lh.V1.thresh.label -f BV20/stats/lh.V1.thresh.label.stats BV20 lh pial_lgi

but I've had no luck with either.

I would appreciate any help!

Thanks,

Krista