Motion Correction (-<no>motioncor)
When there are multiple source volumes, this step will correct for small motions between them and then average them together. The input are the volumes found in file(s) mri/orig/XXX.mgz. The output will be the volume mri/orig.mgz. If no runs are found, then it looks for a volume in mri/orig (or mri/orig.mgz). If that volume is there, then it is used in subsequent processes as if it was the motion corrected volume. If no volume is found, then the process exits with errors.