Here are quick answers to your questions:
1. Resel stands for resolution element. It is calculated as V/FWHM^3,
where V is the search volume (in voxels) and FWHM is the image
smoothness (in voxels). It describes the search volume adjusted for the
underlying smoothness. Clusters are sets of contiguous voxels, above the
threshold you defined, grouped together. You can see clusters as blobs
on your glass brain.
2. Z-score is the voxel value expressed as a standard normal random
variable, or a Gaussian random variable. Unlike t-scores, Z-scores do
not depend on degrees of freedom, hence some people find Z-scores to be
more interpretable. Higher Z-scores are better if you are looking for an
activation, increase, or positive change/effects/differences, whereas
lower Z-scores are better if you are looking for a deactivation,
decrease, or negative change/effects/differences.
-Satoru
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]
On Behalf Of Fatemeh Shahmardan
Sent: Tuesday, September 01, 2009 8:48 AM
To: [log in to unmask]
Subject: [SPM] SPM result
Hello
I have some question about spm result. who can answer me? with alot
of thanks.
1. In the spm table what does nomber of resel & cluster show?
2. what does "Z score" show? higher level of it is better or lower
lever??
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