Nick,
Just a clarification question. I read the wiki regarding the new eTIV and it says that the registration to $FREESURFER_HOME/average/711-2C_as_mni_average_305.4dfp.img is done with talairach_avi as opposed to imgreg_4dfp. I am guessing imgreg_4dfp is correct because the template has 4dfp right in its name. Also, I have not used imgreg_4dfp before, and looking at its options I was curious what a t4file and mode were; two of its listed options. Does this command generate a .xfm file? Thanks.
Chris