Hi AFNI!
I have computed z-scores using 3dttest++ with the -Clustsim flag to correct for multiple comparisons. Everything seemed to be going well until I discovered that for a few of my analyses, I am getting clusters with a peak z-score of 13. For clusters where I get these peaks of 13, when I click around in the cluster, off the peak, I get more regular seeming z-scores (e.g. not whole numbers), and while the other voxels in the cluster often have pretty high z-scores (greater than 7.0), I haven't seen voxels with z-scores above 10. Finally, the area of the clusters where the z-score is 13 is sometimes quite large (100s of voxels), not a single voxel/couple of voxels that peaks usually are. All of the other analyses run with the same script seem fine, producing totally normal z-scores. Could it be possible that AFNI is maxing out z-scores at 13? Or that AFNI sets any z-score above a certain threshold to 13?

Thanks for your help!



Edited 1 time(s). Last edit at 06/29/2020 12:21PM by rbernhard.