The brainmask image was provided by the Montreal group, and is documented in
spm_templates.man as:
% apriori/brainmask
% -----------------
% Image derived from average_305_mask_1mm.mnc, which was originally
% supplied by Alan Evans, MNI, Canada (ICBM, NIH P-20 project,
% Principal Investigator John Mazziotta). The original image
% contained ones and zeros, where ones represented voxels that were
% part of the brain. It was subsequently smoothed using an 8mm
% FWHM Gaussian. This volume can be used to weight the spatial
% normalization so that the final solution is not influenced by
% voxels outside the brain.
It is only a fairly crude representation of the overall shape of the brain,
but it suffices for weighting spatial normalisation etc.
Best regards,
-John
On Wednesday 24 October 2001 19:35, [log in to unmask] wrote:
> Hi
>
> How was the apriori/brainmask.img created? (I found no clue
> in previous messages).
>
> I added WM, GM and csf apriori images. Although the
> resulting image is very similar to brainmask.img, some
> inner voxels have intensities from 0.953 to 1.001
>
> Many thanks.
> Griselda
> Centro de Medicina Nuclear - Univ of SC#o Paulo - Brazil
> http://www.hcnet.usp.br/inrad/sitecmn/neuropsychiatry/neurop
> sychiatry.htm
--
Dr John Ashburner.
Wellcome Department of Cognitive Neurology.
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
mail: [log in to unmask]
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