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Hi Aleksandra, This explains: TFCE considers the spatial signal as spread across multiple neighbouring voxels, something that SPSS cannot do, so neither the same F-test, nor the post hoc t-tests are guaranteed to be significant -- and often they are not, as TFCE is more powerful. That said, even in randomise, the post hoc t-tests may still not be significant, as TFCE doesn't guarantee that the relationship between the F-test and its constituent (post hoc) t-tests are preserved. All the best, Anderson On 5 May 2016 at 00:10, Aleksandra Klimova <[log in to unmask] > wrote: > Hi Anderson, > > > > Yes, I did. > > > > Many Thanks, > > Aleks > > > > *From:* FSL - FMRIB's Software Library [mailto:[log in to unmask]] *On > Behalf Of *Anderson M. Winkler > *Sent:* Wednesday, May 04, 2016 6:07 PM > *To:* [log in to unmask] > *Subject:* Re: [FSL] F test using randomize > > > > Hi Aleksandra, > > Did you use TFCE in randomise? > > All the best, > > Anderson > > > > On 4 May 2016 at 08:11, Dr Aleksandra Klimova < > [log in to unmask]> wrote: > > Hi guys, > > I have ran an F test using randomize which produced significant results. I > then applied threshold to this F test and binarized it in order to create a > mask. Finally, I extracted values in order to run post hoc tests in SPSS > using the binarised F test mask. The Ftest is not significant in SPSS and > neither are the posthoc contrasts. Any ideas why this could be the case? > > Many Thanks, > Aleks > > >