If you just want to calculate the number of activated voxels from the results of your FEAT analysis, just use fslstats thresh_zstat.nii.gz -V on the thresh_zstat image.  The thresh_zstat image is nonzero where the thresholding you selected determined the voxels to be active. 
Is that what you wanted?

2009/8/25 Eric Zalusky <[log in to unmask]>
I am trying to calculate the number of activated voxels in the whole brain.
Am I correct in saying that the zstat is the uncorrected and the thresh_zstat
is the corrected?  If not, what is the difference?

In order to calculate this I am taking the zstat file and using -ztop to get a
pstat image.  Then I use a program in MatLab to calculate global and regional
activation using different masking and a p value = 0.05.  Would this be the
correct way to do this?  Is there a program in FSL to do this calculation?  I
need to have a p = 0.05

Eric Zalusky

Eugene Duff

Centre for Functional MRI of the Brain (FMRIB)
University of Oxford
John Radcliffe Hospital, Headington OX3 9DU  Oxford  UK

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