Hi Sam,

You could do that, but would have to be very careful not to add it to censored time points.
But really, why do it at all?

If the point is to have a better idea of where you are in the brain, that is more appropriately answered with the final_vr_base volume, viewing its registration with the final_anat, and perhaps with the template (to be sure they match). If everything is well aligned, and hopefully it is, then locations in space are better driven using an anatomical underlay.

You can open many connected controllers with the afni GUI (using the black "New" button in the lower left of the main window), and with these locked together, coordinates can come from an Underlay template or final_anat volume, rather than a residual regression data that has no contrast.

Or is it something else? What is driving your interest in having contrast in the residual time series.

- rick