James,
> Perhaps for my purposes the best thing to do is model at least one TR pre-stimulus using TENT, but I'd really like to hear what you
> think about what I've written, and any other thoughts you might have. In the end, I just want my paper to be a faithful reflection of the
> effects we observed.
With TENT, you've already assumed that the BOLD response started earlier than the stimulus onset times.
Here is one thought - How about this empirical approach? Try shifting the estimated HDR of the first (or second) condition rightward (or leftward) along the time axis a little bit until the two curves roughly match at the upstroke phase, and then compare the two curves in terms of their shape differences. That way you would be comparing the two curves after eliminating the anticipation effect.
You may also try CSPLIN/CSPLINzero instead of TENT/TENTzero to get smoother curve comparisons.
Gang