Dear All,
I've been looking at the differences between SPM8 and the NS Toolbox.
It appears that the NS Toolbox is different in two ways:
(1) It adds up the rpv image and multiples the result by cluster
size/number of valid RPV values;
(2) Uses stat_thresh instead of spm_P
In SPM8, the method seems to be to compute the average rpv in the
cluster and multiple it by the intrinsic volume (with surface
correction). Then it uses spm_P.
In looking at the methods, the method of computing resels seems to be
causing the most difference in the NS corrected values. In at least
one case, the resels in the cluster differed by 25% (~4 SPM8 vs ~5 NS
Toolbox).
The question is which method is the preferred method for non-isotropic
smoothness? Any thoughts would be appreciated.
Best Regards, Donald McLaren
=================
D.G. McLaren, Ph.D.
Research Fellow, Department of Neurology, Massachusetts General Hospital and
Harvard Medical School
Postdoctoral Research Fellow, GRECC, Bedford VA
Website: http://www.martinos.org/~mclaren
Office: (773) 406-2464
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