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Dear list, I have followed the recipe from John for a longitudinal study (including two time points of 45 subjects belonging to two groups) using SPM12b: For each subject - Run the SPM12b pairwise longitudinal registration to generate the subject average and Jacobian difference (jd) - Segment the subject average, generating c1, rc1, rc2 - Use ImCalc to compute c1.*jd (possibly dividing the result by the time difference to give the rate of atrophy) - Run Dartel, aligning the rc1 and rc2 images from all subjects together - Normalise and smooth the c1.*jd images - Run stats I have 2 questions: 1. Is it correct to use no bias regularisation & correction in the segment step as the subject average is free of these biases following the bias regularisation during the pairwise longitudinal registration? 2. Should I modulate or not in the "normalise and smooth"-step. It says for vbm it is recommended but I found an email in the archives in which John states that this question is a good one. :) Just wanted to know: is it still? Thank you! Vincent Brunsch