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| I am using SPM for VBM analysis, and I am interested in the correction for | the Jacobian parameters. I have tried it on a couple of brains and applied | it to the normalized image, and noted an interesting phemomenon. In brains | with a large degree of atrophy | the segmentation done after the Jacobian-modulated process is much less | accurate than a segmentation done before after normalization, but without | Jacobian modulation. The gray matter is wider and less well-defined, and | there is more 'noise' in regions such as the ventricle and the around the | basal ganglia. Does this make sense? | | Since I am using the segmented images for VBM analysis, would it make any | difference if I apply the Jacobian modulation to the segmented image rather | than the normalized unsegmented image. The modulation should be done on the grey matter segments, rather than the normalised images themselves. Best regards, -John %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%