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Hi - seems like something's wrong here - increasing tfce_tstat should definitely lead to increasing tfce_p_tstat (it does for me!). Are you definitely comparing images from the same run of randomise and the same contrast? Cheers. On 20 Oct 2008, at 19:22, Ashley DeMarco wrote: > Gwenaelle, > > We have been thresholding the p-tstat maps from .95 to 1 to observe > the > significant voxels, since 1-p is the convention used to generate the > p-tstat > maps. > > I think I miss stated what we are seeing on our maps in my previous > post. > > As the values on the tfce p-tstat map increase, the tfce tstat map > values > decrease. Example: for one of our voxels our tfce p-tstat value is . > 952 (p > of 0.048) and our tstat map value is 16694, then on another voxel, > our tfce > p-tstat is .99 (p=.01) and our tfce tstat is 12686. > > (We aren't using corrp at this time because we have such a small n) > > Most of the other cases that we have looked at when we have run the > randomise tool as mentioned had the proper relationship between the > p-tstat > and the tstat. > > So our 2 concerns are: > 1. How can we get out tstat values down so they are appropriate for > the p > values we are getting > 2. Figuring out why we got p-values and t-stats that had the opposite > relationship on this run > > Thanks for all your help, > Ashley > --------------------------------------------------------------------------- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ---------------------------------------------------------------------------