If you have suitable tissue probability classes to use as priors, then you should be able to call spm_preproc using these as arguments. You won't be able to do it via the standard GUI though, and you may need a bit of additional MATLAB coding in order to get it to write out the segmented images. Best regards, -John ________________________________ From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of kamran kazemi Sent: Monday, May 21, 2007 12:05 PM To: [log in to unmask] Subject: [SPM] segmenting 4 classes in SPM Dear SPMers SPM5 can segment 3 classes (GM, WM and CSF) normally, but maybe can segment 4 classes if one change the segmentation program. i want to know if one did this changes or how i can do it. Kind Regards kamran ________________________________ Need a vacation? Get great deals to amazing places <http://us.rd.yahoo.com/evt=48256/*http:/travel.yahoo.com/;_ylc=X3oDMTFh N2hucjlpBF9TAzk3NDA3NTg5BHBvcwM1BHNlYwNncm91cHMEc2xrA2VtYWlsLW5jbQ--> on Yahoo! Travel.