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Thanks, Matthew! Actually, we're using the SVC only to test for significance...not using the voxel value to correlate with anything else. And I agree with the argument presented in the marsbar description, but to reply to the reviewers I'd prefer to cite a peer-reviewed publication that argues for the validity of using the SVC approach as opposed to ROI. On Fri, May 1, 2009 at 1:42 PM, Matthew Brett <[log in to unmask]>wrote: > Hello, > > On Fri, May 1, 2009 at 10:36 AM, Lilly Mujica-Parodi > <[log in to unmask]> wrote: > > All: > > > > I need to respond to a reviewer who complains about our having used a SVC > > analysis rather than an ROI (averaged) analysis. I've seen bits and > pieces > > of responses as to the conceptual advantages of SVC as compared to ROI > > analyses, but never a comprehensive justification. I'm thinking that > surely > > one must exist, right, since SPM5 onward doesn't even support ROI > analyses > > anymore? > > Did you catch this? > > http://marsbar.sourceforge.net/faq.html#svc > > It has some small discussion of the topic. You also may have seen the > recent Vul et al paper complaining about _plotting_ peak voxels from > SVC corrections. The argument would be that it is valid to do small > volume correction to test significance, but you should not use the > peak t value or the plots from the peak voxel to add to your argument, > because they will now give a biased impression of the strength of your > effect. > > Best, > > Matthew > -- Lilianne R. Mujica-Parodi, Ph.D. Director, LSEC Dept of Biomedical Engineering Dept of Psychiatry Stony Brook University Health Sciences Center T18 Stony Brook, NY 11794 office: 631-444-9993 lab: 631-444-7868, 631-444-9232 http://lsec.bme.stonybrook.edu/Site/Welcome.html