I'm working with a data set which has been analyzed entirely in the subjects' native spaces in Freesurfer, but now I would like to run a group analysis on the data. Is it necessary to re-run the preprocessing and contrasts in normalized space, or is there a small set of files that are looked for by the group analysis scripts (isxconcat-sess?) that I might be able to register to mni305 space and run the group analysis from there?  

Thanks!

Terri