Dear Michele,
It's all to do with left and rights. Historically, and I'm not going to go into
why, versions of SPM96 onwards have laterally flipped the brain during the
normalization process. Usually PET or fMRI data is collected in 'radiological
convention' that is the left side of the image is the right side of the subject,
or, as I look at it, when you look at an axial view of a brain, it is as if you
are looking from the feet up. After normalization (if you leave the defaults as
they are) the brain will be flipped into 'neurological convention' with the left
side of the image being the left side of the subject. Again, using my view, when
you look at an axial image it is as if you are looking down from above the
subject. If your data is collected in neurological convention or you do not wish
to flip your images then you can change the defaults in the normalization,
affine starting estimates option. NB: The spm templates are not symmetrical, so
I would leave things as they are unless you have a good reason not to.
Cheers.
Alex.
> Dear SPMers,
>
> I have a very quick question re normalization. When I finish the
> normalization step, what does "image flipped" mean and what do I have to
> do in this case?
>
> Thank you,
>
> Michele.
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