Antonella Kis wrote: > Dear Freesurfer experts, > > I am doing a thickness-age correlation group difference study (patients > versus controls. I would like to know if: > > 1) my contrast vector defined as 0 0 0.5 0.5 is correct in order to test the > change in thickness with age > Yes. > 2)what is the best iteration number for the simulation? Should be 5000 or > 1000 or greater? > 10,000 -- note that if you're doing a whole-hemisphere correction with the monte-carlo simulation then you should use the pre-computed results (use the --cache option to mri_glmfit-sim) > 3)why when I run the simulation for 5 iterations I've got zero clusters? > You should look at your data to make sure that you have actual activation above the voxel-wise threshold you have set. Also, only 5 clusters would not be enough to get a significant cluster anyway. > 4)can I derive the thickness from the significant clusters of glm analysis? > Do I need to run QDEC after GLM? > If you mean that you want the average thickness from each subject for a given cluster, then this information is generated with mri_glmfit-sim in the csdbase.y.ocn.dat file.
doug > Thanks for any enlightenment. > Antonella > > > ------------------------------------------------------------------------ > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
