Hello,

First, thanks for the great tool. I have been using it a lot over the past year to look at small volume corrections, primarily using uncorrected p values and a cluster extent from AFNI's 3dClustSim, which has worked great--and I have done some sanity checks to verify that I get the same results looking across a few different result viewers (pickatlas, SPM's results viewer with a mask and SVC, and Aaron Schultz's OrthoView/FIVE). Recently we've run some SVC's for the amygdala trying to use voxelwise FWE correction, but we cannot get the same results in the pickatlas and SPM. Do you have any thoughts on why this might be the case?

I have looked at the results in pickatlas and SPM (8 and 5) installs on several machines and see the same thing each time--several significant clusters for amygdala SVC FWE 0.05 in pickatlas (yay!), but none in SPM (not yay!). I make sure the stats are updated in pickatlas after I apply the mask. And in SPM I set p to FWE 0.05, then click small volume correction and select the image for bilateral amygdala that I saved from the pickatlas.

I noticed there were fewer voxels included in the spm analysis because it is applying the mask.img (which it looks like the pickatlas isn't doing?), so I created a new bilateral amygdala mask in imcalc as the intersection of the mask.img with the bilateral amygdala mask. Then I used that to run SVC in both pickatlas and SPM, which gave the same number of voxels being analyzed in both, but still the same issue of significant results in pickatlas and none in SPM.

Any insight you might have would be a great help!

Thanks,
Brad

----
Bradley C. Taber-Thomas, Ph.D.
Postdoctoral Fellow
Cognition, Affect, and Temperament Lab
bct3@psu.edu