[log in to unmask]" type="cite">Deer all,

I have run into a strange behaviour of SPM and might need some help. I am a master student and run a fMRI study, and on one subject I had to us the reorientate procedure to reset the point of origin into the AC. This was necessary, to get usable results from the segmentation process. But when I applied the reorientation to all the EPIs of the subject, the movement parameters, which are estimated by the realigment module changes. As it is my understanding, that the realignment procedure only gives you relative movements (in my case to the first EPI), how is this possible?
The reorientation happens in the y and z axis and the change affects all translation parameters, but not the rotation parameters.
I also would like to now, which one of the movement parameters should I use for ascertaining the subject movement and as regressors in the analysis?

Many Thanks in advance,
 Stefan Greulich