We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:
https://discuss.afni.nimh.nih.gov
Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.
The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.
At present, there isn't a way to do this in 3dttest++. I would have to derive the formula for t-testing the covariate slope estimates (taking into account covariance between the covariates), and then implement it.
At the present moment, I am deeply involved in developing a response (both in the AFNI code and in a manuscript) to http://www.pnas.org/content/113/28/7900.full and so don't know when I will get around to this testing subject.