> > We have been running spm2 preprocessing using the optimized method
> (optvbm) on structural MRI scans of people at various stages of psychoses
> and matching controls.
> The gray.mnc and white.mnc apriori templates used in
> normalization.....are they suitable for the ages 16-30 in a clinical group
> with psychoses, or should we create our own apriori templates (like Good et
> al. 2002).
I would expect the default priors to be reasonable in terms of age etc.
Statistics about the subjects can be obtained from spm_templates.man:
% Subject details:
% Age: mean=25.0, median=24.0, mode=19.0, stdev=4.9, range=18-44
% Sex: female=66 (43.4%), male=86 (56.6%)
% Handedness: right=129 (90.2%), left=14 (9.8%), unknown=9
I don't know how far the brains of subjects with psychoses differ from
the subjects used to make the prior probability images (I guess that is
what you intend to find out). I cannot imagine it is likely to be a
large difference though.
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
|