Hi Anastasia,
My fault. That works in the other direction (orig->tlrc)
because afni has a pre-defined grid for +tlrc datasets.
But there is no pre-defined grid for +orig datasets, so
the tlrc->orig direction requires you to specify one.
That means you would have to use 3dfractionize (or 3dWarp
with a -gridset option and your transformation matrix).
3dfractionize -template grid+orig -input data+tlrc \
-warp anat+tlrc -preserve -clip 0.2 -prefix data
In your case, the grid+orig dataset might be the +orig version
of anat+tlrc. Though I guess that might not be true. It
depends on what you want to do with your ROI dataset.
- rick