Thanks a lot for your help, Ziad.
I think -tzero 0 makes sense for our data.
We choose .hdr formatted datasets since we may use other software late.
Just wondering if we can get same results from tshift or other afni routines when using NIFTI format or Brik format. Are the timing information recorded in .hdr header? if not, it seems we do need to use Brik format data.
Thanks.
Jian