Hi Darren and Helmut,
hmm, I think we all pretty much agree on this.
The space defined by the 152-templates can clearly be described as "MNI space", as there are good reasons to believe that these spaces are (close to) identical. When we normalise a brain to one of those templates the brain is (I would say) in "approximate MNI space", approximate because of the limitations of normalisation. As we add more subjects the "average" of those individual normalised spaces should further approach that of the MNI space. Hence, when we have normalised to one of those templates I think it makes sense to say the we "are in MNI space".
The EPI template were created by normalising gray matter segments from mean EPIs to the gray posterior probability map, which is in MNI space. Hence, the EPI is also in "approximate" MNI space, but since it is based on different (and much fewer) subjects than the MNI 152-templates it is not identical to (or _in_ ) MNI space. If one says that the EPI template is _in_ MNI space, then I think one could equally well say that the MNI template is _in_ Talairach space, since the MNI images were all normalised to the Talairach space prior to averaging (albeit with a lower df transform).
I think we will just say that the images were normalised to the SPM2 EPI-template, and leave it to the reviewer to decide just what space that is.
Puss Jesper
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