Hi, Jack-
NB: in general, we recommend **not** doing global signal regression, with some discussions of this provided here:
[
www.ncbi.nlm.nih.gov]
[
www.ncbi.nlm.nih.gov]
[
www.biorxiv.org]
[
www.ncbi.nlm.nih.gov]
If, however, you are interested in using for a comparison, say, then Rick has noted the way to do so in afni_proc.py here:
[
afni.nimh.nih.gov]
--pt