Hi All, Sorry if this is a very naive question, but I am very new to SPM and am in the process of learning to use it to analyse FDG-PET data. I have set up a 2 sample t-test, and specified the contrast as 1, -1. However when I click 'submit...' the contrast does not apply and an error message is displayed in the matlab window: Error in ==> spm_conman at 1271 [c,I,emsg,imsg] = spm_conman('ParseCon', str, xX.xKXs,STAT); ??? Error while evaluating uicontrol Callback. I am running SPM8, but seem to have been able to make the contrast work with SPM5 on a different machine. Has anybody else had this problem? Am I just doing something very silly. Any help you could offer would be greatly appreciated. Kind regards, - Charles -- Charles Malpas MPsych (ClinNeuro) / PhD Student Psychological Sciences & Department of Medicine (RMH) The University of Melbourne Phone: 0451 116 434 Email: [log in to unmask] Skype: charles.malpas