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Dear SPM'ers, I have 2 questions regarding VBM in SPM5. I performed a covariate-only analysis to identify regions where the degree of atrophy is significantly correlated with some psychological scores. I used all default options and an absolute threshold mask of 0.05. Now, for each region, I would like to extract a value that I can use in SPSS to perform, i.e., a multiple regression, to then calculate the predicting value of each region on the psychological score. If it was an fMRI study, I would first plot the fitted responses/adjusted value over scans, then I would extract the beta values by typing y in matlab. If I do the same in VBM, what measure do I obtain? I suppose it is a measure of gray matter density per voxel, but I do not know exactly what it is called.* *My questions are therefore 2: 1) Does it make sense to extract density values and perform a regression outside SPM using SPSS or would that be a "circular" procedure? 2) What am I measuring when I extract what I call the beta values in VBM? Thanks! Giovanna Giovanna Zamboni, MD Cognitive Neuroscience Section NIH/NINDS