Chris,
To augment Karl's answer...
> 2. Has anyone at the FIL or elsewhere ever implemented the MSOS test in
> Matlab? Was the modification to the Activation Proportion test proposes in
> Worsley (above) ever integrated into a previous version of SPM, or
> elsewhere? I would be extreemely grateful for even guidance on how to
> implement these if no such code already exists.
A more general version of Worsley's 1995 work is that for the average of
F fields [Neuroimage (1997) 6(4):305-319]. The voxel-wise square of a t
image is a F image, and F images can be used to test sets of contrasts or
effects, not just one.
I coded up Worsley's average F work in a rudamentary way and Matthew
Brett has wrapped this into (what I think is) a useful function.
With Matthew's permission, I've attached the SPM96 version of the function
(is_effect) and the SPM99 version of the function (meanF).
The SPM96 version simply assesses the F image (testing the hypothesis that
all experimental effects are zero) for a given analysis. The SPM99 version
allows you to specify a F contrast to test.
Standard caveats (use with caution, don't sue anyone, don't drink and
derive) apply.
-Tom
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