afni.nimh.nih.gov

Dear Gang,

I hope you're keeping safe and well.

I've been running a number of LMEs as follows. At risk of having totally missed something obvious, I think I've spotted an issue with the calculation of the z-score of voxels within post-hoc GLTs. For posterity, I'm detailing the issue here.

3dLME -prefix /data/gcooper/movie_delay/LMEs/LME_"$stat"_inny.nii.gz \
-resid /data/gcooper/movie_delay/LMEs/LME_"$stat"_inny_resids.nii.gz \
-model 'movie*moviepart+age+gender' \
-jobs 20 \
-ranEff '~1' \
-qVars "age" \
-qVarCenters "26.81" \
-num_glt 4 \
-SS_type 3 \
-gltLabel 1 'all' -gltCode 1 'moviepart : 0.333*beginning 0.333*middle 0.333*end' \
-gltLabel 2 'BvM' -gltCode 2 'moviepart : 1*beginning -1*middle' \
-gltLabel 3 'BvE' -gltCode 3 'moviepart : 1*beginning -1*end' \
-gltLabel 4 'MvE' -gltCode 4 'moviepart : 1*middle -1*end' \

The weirdness begins with glt4; 'all', which I'm using to calculate the mean effect of each level of the 'moviepart' factor. The main output of 'all' correctly contains some very large mean values (>120). All voxels containing a mean score greater than some mystery threshold are being assigned a z-score of zero in the subsequent 'all Z' brick.

I've since side-stepped the issue, as the z-score of these voxels can be correctly calculated 3dcalc -expr 'atanh(a)'

Is this a known issue? Is it an issue at all?



Edited 1 time(s). Last edit at 03/02/2023 10:46AM by gregetarian.