Hi Daniel,

Thank you so much for getting back to me. I am still not convinced that these z-scores of 13 are not some kind of error. Particularly because the t-values for these voxels produced by 3dttest++ do not seem to be extreme (or not more extreme then the t-values for neighboring voxels). For example, voxel A has a t-score of 10.65 and a z-score of 13. It's neighbor, voxel B, has a t-score of 10.23, but a z-score of 8.13.

For what it's worth, the command I am running is as follows:
3dttest++ -prefix belvthink_belvdesthink_1 -setA shellgame_*_belvthink_resampled* -mask belvdesthink_1_dilate1+tlrc -Clustsim 8

Just to make sure it was not some kind of issue being produced with the cluster correction, I reran this analysis without -Clustsim but including the -toz flag as follows:
3dttest++ -prefix belvthink_belvdesthink_1 -setA shellgame_*_belvthink_resampled* -toz -mask belvdesthink_1_dilate1+tlrc
This produced the same aberrant z-scores so it seems as though the error is occurring in the t to z conversion that is done with -toz. Can you tell me a little bit more about what happens in -toz? How does AFNI convert the t-scores to z-scores?

Thank you again for your help!
Regan



Edited 1 time(s). Last edit at 07/13/2020 10:58AM by rbernhard.