[Freesurfer] Extracting thickness values using labels

Dear Freesurfers,

This is probably a very basic question, but I was unable to find an answer in the mailing list:

I did a paired cortical thickness group analysis:

mris_preproc --fsgd /home/paired.fsgd --target fsaverage --hemi lh --meas thickness --out lh.paired.00.mgh --paired-diff

(smoothing)

mri_glmfit --y lh.paired.05.mgh --fsgd diff.fsgd --osgm --surf fsaverage lh --cortex --glmdir lh.05_diff.glmdir

I found an area of difference in cortical thickness and I would like to know the thickness values of this area for all of the input in paired.fsgd, not just the differences I get from the y.ocn.dat file.

How do I extract thickness values from the lh.paired.00.mgh file using the label file of the significant cluster?

All the best, Anders