Hi Aditya,

Use 'adwarp' only for applying a +tlrc (or +acpc) transformation to
a +orig or +acpc dataset. The resample operation should be performed
with either 3dfractionize or 3dresample, depending on whether you want
to use voting and a cutoff or to use interpolation (but maybe nearest
neighbor).

For example:

3dresample -master ../002_at+tlrc -input Lamyg1_Ramyg2+tlrc \
-prefix amygdala_resampled -rmode NN

See '3dresample -help' or '3dfractionize -help' for details. A more
visual depiction of what 3dfractionize does can be found on slides
13-16 of the ROI class handout:

[afni.nimh.nih.gov]
[afni.nimh.nih.gov]

That "overwriting" warning is an overzelous message because the .HEAD
file is written before the .BRIK file, at which point the software
feels it is overwriting the dataset.

When you are trying to duplicate some output grid, it is essential to
have an option like '-master', because even if you get both to 2x2x2
for example, the number of voxels in each direction may still differ.

- rick