Thanks (yet again) Rick!

That seemed to work beautifully. At the point we'd like to do an analysis that I'm told is easy in SPM, but I don't know how to do with AFNI. Maybe you can point me in the right direction.

For regressor R (which represents some condition x trial part) on subject S, I would like to extract the ROI's average value for the TRs during which R is "on" (with some padding to the left and right). Then, I'd like to come up with one averaged timecourse that represents the average of all those individual timecourses. This represents the average value in the ROI during R (as a time course) for S.

I can then compare this timecourse across subjects (for group analyses) and across regressors.

What I've described probably already has a name, but I have no idea how to do it. Now that I have full ROI timecourses for each subject, I could imagine writing a script to do it -- except that 3dDeconvolve does nice things like polort and HRF delay (so it will pick better TRs than I would).

Cheers,
A