afni.nimh.nih.gov

Hi all,

I've been looking through the 3dttest++ documentation as well as some afni slides and I have a few doubts.

1) What mask should be provided when using the -clustsim option? I haven't been able to find masks of the various atlases under ~/abin. Should I generate one? Or perhaps should I use one of the masks generated by afni_proc.py, such as mask_group+tlrc? Speaking of which, what are these masks for?
2) Why are the statistics skewed if a mask is not used, as specified on the 3dttest++ help page?

Thank you,

Ruy