Dear Douglas I try the analysis of volume and other indexes, not just thickness. I was confused that why the data of volume for each subject was so small (data in the file of cache.th13.pos.y.ocn.dat, e.g 1.39463 1.50616 2.53250) after using the command of mri_glmfit-sim (mri_glmfit-sim --glmdir aaa.thickness(or volume, sulc).lh.10 --cache 1.3 pos --cwp 1 --2spaces).

Could you tell me the unit for each index (e.g thickness, volume, sulc,pial_lgi)?

Thank you