I do have couple questions about using mri_glmfit and mri_glmfit-sim for this analysis based on the tutorial page. https://surfer.nmr.mgh.harvard.edu/fswiki/PetSurfer

 1) Do i have to add any other flags when using mri_glmfit for this analysis?
mri_glmfit --y ${results_dir}/all.mgx.subctxgm.mni305.sm05.nii.gz --fsgd $pet_fsgd --C $matrix1 \
--mask ${SUBJECTS_DIR}/fsaverage/mri.2mm/subcort.mask.mgz --glmdir ${results_dir}/sub.pet.B6.glmdir

2) When correcting for multiple comparisons, should i use --2spaces or --3spaces?

3) I ran a paired ttest analysis using age as regressor of no interest for amyloid uptake. My contrast is  "1 0" based on the tutorial https://surfer.nmr.mgh.harvard.edu/fswiki/PairedAnalysis. 

How do i interpret the direction of contrast if I get a result from mri_glmfit-sim (see below)? This is because it doesn't have the Max column for surface based analysis
# Cluster   Size(n)   Size(mm^3)     MNIX   MNIY    MNIZ              Max    CWP    CWPLow    CWPHi
  1        12709      101672.0      26.00  -69.00  -41.00           5.46844  0.01037  0.00798  0.01316  Right-Cerebellum-White-Matter

Thank you. 

best, 

Paul