Dear Mr or Ms, I have read the FreeSurfer Tutorial: Group Analysis, but there are still something I do not quite understand. I want to make comparison of lgi between two groups, namely, normal control group and patient group. I want to regress out gender and age.For example,if I have 4 subjects: nc1 male age=30,nc2 female age=31,patient1 male age=32, patient2 female age=30, how should I create the FSGD file?How should I design the constrast vector? What kind of test does Freesurfer use,F-test or t-test to detect difference region of thickness or lgi on the surface? What should I do if I want to use t-test to detect the difference between two groups? How should I set the option of the command mri_glmfit --sim nulltype nsim thresh csdbasename if I want to set the p-value threshold 0.05? Sorry for the trouble! Thank you very much! Yuanchao Zhang
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Have you looked at my presentation on group analysis? The slides are here:
http://surfer.nmr.mgh.harvard.edu/docs/ftp/pub/docs/freesurfer.groupanalysis...
There's a very similar design on slides 23 and 24.
doug
Zhangyuanchao wrote:
Dear Mr or Ms, I have read the FreeSurfer Tutorial: Group Analysis, but there are still something I do not quite understand. I want to make comparison of lgi between two groups, namely, normal control groupand patient group. I want to regress out gender and age.For example,if I have 4 subjects:nc1 male age=30,nc2 female age=31,patient1 male age=32, patient2 female age=30, how should I create the FSGD file?How should I design the constrast vector? What kind of test does Freesurfer use,F-test or t-test to detect difference regionof thickness orlgion the surface? What should I do if I want to use t-test to detect the difference between two groups? How should I set the option of the command mri_glmfit --sim nulltype nsim thresh csdbasename if I want to set the p-value threshold 0.05? Sorry for the trouble! Thank you very much! Yuanchao Zhang
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