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Hi Anne, The modulated images have _mod in the filenames while the unmodulated ones do not (e.g. GM_mod_merg vs GM_merg). You can also find the Jacobians in images with _JAC_ in the filename. The "traditional" style of VBM was not around for very long before the "optimised" one replaced it, precisely because it takes into account both sources of changes (intensity changes and volumetric ones, as inferred from the registration). I would advocate that you should only use VBM with the modulation. Reporting DBM is certainly an alternative, although I believe that it is generally less sensitive on average and that this is why VBM is still more commonly used. I hope this helps. All the best, Mark On 1 Aug 2012, at 14:32, Anne Bailey wrote: > Hello all, > > I am working with FSL's optimized VBM protocol and would like to separate the output into un-modulated VBM values and analyze the Jacobian determinants as a DBM measure. Has anyone reported these two measures separately previously? Can anyone point me to some references? > > I find that the end product of optimized VBM actually confounds these two pieces of information and hard to compare with previous findings that reported the more traditional style of VBM (i.e., unmodulated) OR have reported only DBM. > > Thanks in advance for any input on this! > > Anne > > -- > Anne Bailey, Ph.D. Candidate (Clinical Psychology) > Laboratory for Motor Learning and Neural Plasticity > Concordia University > 7141 Sherbrooke Ouest > Montreal, Quebec > H4R 1B6 > (514) 848-2424 ext. 7567