Richard, Just the input data is smoothed (during the recon-all -qcache stage run outside of qdec).
The patches that appear in a results display are not 'patches' in any explicit sense, but just what is displayed due to the default thresholds that qdec uses. You can adjust those thresholds via the controls in the Display panel in the bottom left-hand corner, either by entering values or using the histogram (which can take a little practice). These do not change the actual p-values, only the color table displaying them, allowing you to see larger or smaller patches. Nick On Mon, 2008-12-08 at 09:27 -0600, Richard Frye wrote: > From my understanding qdec fits a glm to each vertex. It also smooths > the data. > > From the documentation I do not have a clear understanding of whether > qdec uses smoothed data for input (It appears that is does) or smooths > the coefficients or t-tests after analysis, or both. > > Additionally, the resulting contrast results appear to have patches of > significance. What is the processes that makes patches out of > individual vertex results? Do a certain number of contiguous vertexes > need to be significant for their values to be connected into a patch? > > -- > Best Wishes, > > Richard E. Frye, M.D., Ph.D., F.A.A.P. > Assistant Professor of Pediatrics and Neurology > University of Texas Medical School at Houston > 7000 Fannin -- UCT 2478 > Houston, TX 77030 > Office: 713-500-3245 > e-mail: [EMAIL PROTECTED] > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
