afni.nimh.nih.gov

Dominic,

> would the output sub-brik of Control-Experimental_AgexAnxiety be correctly showing me the 3-way interaction I am interested in testing?

Yes, that would be what you're looking for. One thing you should be careful is centering. I suggest that you center 'age' and 'anxiety' first yourself, and obtain their product for AgexAnxiety, and then feed them as three covariates in 3dttest++ with option '-center NONE'.

Gang