 |
 |
Dear Adrian, for VBM type analyses, standard SPM cluster size correction should not be reported because of the spatial non-stationarity of error. You may want to try the results reports from Christian Gasers VBM5 toolbox, but they are not yet properly integrated in SPM5 - Christian and me are trying to find a solution for this problem. Volkmar On Thu, 4 Oct 2007, Adrian Imfeld wrote: > Hi SPM users, > > I'm analyzing DTI data with SPM5 and I'd like to do group comparisons > (n1=13, n2=13) of fractional anisotropy images and within group correlations > of anisotropy with a performance score. I'm trying different smoothing > kernels (4x4x4mm vs. 8x8x8mm) and different alpha-levels (p<0.01 vs. p<0.05, > uncorrected). > > Question 1: After inspection of the SPM5 statistical tables, I'm inclined to > use smoothing with 8x8x8mm and an alpha level of 0.05. Do you think this is > reasonable or would you use other parameters? > > Question 2: The size of clusters seems more important to me than their > Z-value peek voxel. Is it okay to focus on the cluster-level analysis > (p_corrected column) instead of the voxel-level analysis? > > Any help is highly appreciated. > > Regards, > > Adrian Imfeld > -- Volkmar Glauche - Department of Neurology [log in to unmask] Universitaetsklinikum Freiburg Phone 49(0)761-270-5331 Breisacher Str. 64 Fax 49(0)761-270-5416 79106 Freiburg http://fbi.uniklinik-freiburg.de/