Elisa,

I would like to have some clarifications from you before I could offer suggestions.

> I need a way to control for RTs in the ANOVA, that is, remove that part of variability
> that is due to differences in RTs across conditions. Now, having the ABI map that
> tells how activity in each region is modulated by RTs, how can I use it to remove,
> for each voxel, the modulations driven simply by RTs, and not by my factors of interest?

The RT value varies across trials of each condition (liberal or conservative for criterion and hits or correct rejection for item type), and you've already modeled the RT variability across trials in individual subject analysis with 3dDeconvolve through the modulation approach. Now there is an average RT value for each of the four conditions (2 x 2: criterion-by-item type) from each subject, and these four *average* RT values also vary across the four conditions as well as across subjects. When you say that you would like to control for the RT variability in ANOVA, do you mean using these *average* (not trial-level) RT values at group level? Or are you referring to something else?

Gang