Dear Karel,
> How is the mask.img image calculated i.e. how is decided which voxels
> will be included in statistical analysis? I noticed in some mask images
> that white matter is excluded from analysis, how come?
It uses an intensity thresholding technique. Thus, it calculates a sort of
average in-brain voxel value with:
m1 = mean of all voxel values in the image
gm = mean of all voxel values in the image that are greater than m1/8
(line 57 of spm_global.c)
and then rejects from the analysis any voxel that has a voxel value that is
is less than the gm for it's own scan (for fMRI - for PET, < gm /0.8 by
default).
> I want to calculate the inverse image of the mask.img to see what
> regions in the brain are not incorporated in the statistical analysis.
> How do I calculate the inverse image of the mask.img? I suppose I have
> to use ImCalc but what function do I enter?
i1 == 0
Best,
Matthew
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