> I have a set of spatially normalized images and they are ready for SPM
> analysis. Nowever, if I am now only considering to do analysis on
> supratentorial regions only, I can think of 3 ways but am not sure which
> one is better.
>
> (1) cropping unwanted slices of all subjects. For example, if all
> unwanted slices are below slice 63, then I can crop slices from 1 to 63 for
> all subjects as they are all in-register.
If you do any cropping of this kind, then it is best to do it on the
spatially normalised images, after you have smoothed them.
> (2) creating a binary mask of all 0s below slice 63 and all 1s above 64.
> Then using this mask when I do the analysis.
This is probably the best solution, although I don't know how easy it is
to do explicit masking in the fMRI stats of SPM2.
> (3) crop unwanted slices of the original images before normalization.
This is probably the least desirable way of doing it.
Best regards,
-John
--
Dr John Ashburner.
Functional Imaging Lab., 12 Queen Square, London WC1N 3BG, UK.
tel: +44 (0)20 78337491 or +44 (0)20 78373611 x4381
fax: +44 (0)20 78131420 http://www.fil.ion.ucl.ac.uk/~john
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