Hi Doug, I have two groups of subjects and I want to study the difference in cortical thickness between the groups. I used Qdec to run the analysis and I got significant difference between the groups in areas support what I am looking for. I repeated the analysis as mentioned in Wiki https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/GroupAnalysis
1. My data is previously cached so I ran the command : mris_preproc --fsgd gender_age.fsgd --cache-in thickness.fwhm10.fsaverage --target fsaverage --hemi lh --out lh.gender_age.thickness.10.mgh
2. GLM analysis: mri_glmfit --y lh.gender_age.thickness.10.mgh --fsgd gender_age.fsgd dods --C lh-Avg-thickness-age-Cor.mtx --surf fsaverage lh --cortex --glmdir lh.gender_age.glmdir
3. Correction for multiple comparison mri_glmfit-sim --glmdir lh.gender_age.glmdir --cache 4 neg --cwp 0.05 --2spaces
Surprisingly, the results are totally different from what I get in Qdec. I checked Qdec's commands generated in Terminal and I noticed that it uses the command "mri_surfcluster" instead of " mri_glmfit-sim "
Kindly,
1. What is the difference between "mri_surfcluster" and " mri_glmfit-sim "
2. Is it expected that we get different results as an output of the previous two different methods
3. In order to run statistical analysis regarding volumetrics and cortical thickness. Which method is more advisable, Qdec or the previous command lines (1-3)
Best, Mohamad