Sorry for being slow on this...
RetroTS is a matlab function written by Ziad to convert those
time series into respiration volume per time signals, as well
as respiration and cardiac phase signals.
See this message board thread for details:
afni.nimh.nih.gov
The AFNI matlab package, of which RetroTS is a part, is here:
afni.nimh.nih.gov
That makes one regressor file per run, which can be passed
to afni_proc.py (see examples 5 a,b and c from the help).
- rick