Hi Ekaterina,

Those results (where all of the p-value columns still have no numbers in them and simply show '---' symbols) simply mean that the TFCE voxel-level statistics have still not been computed. TFCE requires randomization analyses to be run in order to compute p-values associated with each TFCE value (which can take a while, depending on the size of your dataset), after those are finished those '---' columns will be filled with the actual p-values associated with those TFCE values and you will be able to threshold the results normally. When you select TFCE you should be getting a prompt that asks you how do you want those permutation/randomization analyses to be run, you can specify there whether they should be run remotely (e.g. on a HPC cluster) or in this computer. Either way, after that simply wait (do not cancel those analyses) and when they are finished you will get a "normal-looking" results figure.

Hope this helps

Alfonso

Originally posted by Ekaterina Pechenkova:

Hello,

I'm puzzled by suspicios results for the voxel-to-voxel analysis with TFCE. While the RFT or regular non-parametric stats (cluster mass) result in a couple of small significant clusters, the TFCE shows almost all the brain covered by huge significant clusters and indicates a threshold of TFCE>0.00 and no calculations of p-values been done (see screenshot attached). Setting a more conservative p-value changes nothing.

I observe the same thing for different voxel-to-voxel measures (ICC, ILC, MVPA) and in at least two different versions of Conn (20b, 22a), for two projects at hand and for different contrasts in these projects.

Before I didn't use TFCE for connectivity analysis and only had experience with TFCE in the context of TBSS (DTI) analysis in FSL which does not tend to produce anything like this. 

What am I doing wrong? Or does it mean that nothing is actually significant?

The results screen illustrating TFCE on Conn site looks very reasonable and different from mine: https://web.conn-toolbox.org/fmri-method...

Could anyone please comment?

Thank you!