411 REFERENCE · Wikibooks
SPM/Normalisation
Reference material by Wikibooks contributors. This retains its source identity and is not 411 news reporting.
In order to compare data from several scans and / or research subjects, all the brain images have to be in the same 3D space. In SPM this is accomplished by "normalizing" the images into the space defined by the Montreal Neurological Institute (MNI) template. Different versions of SPM use different algorithms for this process. In general, the closer the images start out to the MNI template orientation, the better the outcome of the normalization.
Links
Spatial normalization