afni.nimh.nih.gov

> For the group analysis, I want to look at reaction time as a regressor on a trial by trial basis
> between the young and old group. In each trial, the duration of the stimulus and trial was
> held constant. I think I only want to model the BOLD amplitude based on this design, correct?

Yes most people use the effect associated with the first basis function in SPMG2 for group analysis for its simplicity.

Gang