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| Very simple question: Can anybody tell me what exactly the  'N vox'
| values in the segmentation Output window mean, where the difference
| between these values and the N pix values in SPM96 is and finaly if
| there is any conection between these Values and the actual Number of
| Voxels in the brain which are GM/WM/liquor.

The segmentation estimates the classification from a subset of voxels
within the image volume.  N vox is simply the proportion of these voxels
that is classified as the different tissue types.  In SPM96, N pix was
the number of voxels within the subset, that were classified as the
different types.

The values are loosely related to the number of GM/WM/CSF voxels in
the brain, but a better indication would be obtained by integrating the
contents of the *_seg*.img files:

	V   = spm_vol(spm_get(1,'*_seg*.img'));
	vol = 0;
	for i=1:V.dim(3),
		img = spm_slice_vol(V,spm_matrix([0 0 i]),V.dim(1:2),0);
		vol = vol + sum(img(:));
	end;
	fprintf('%g voxels, %g litres\n', vol, vol*det(V.mat(1:3,1:3))*1e-6);

Regards,
-John



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