Hi Gang,
I would like to follow up to ensure I'm doing this correctly. For my model, I'm permuting the data (I won't get into the specifics here) and generating one whole-brain Z-statistic map per permutation. As a start, I've generated maps from 2000 permutations, and then 3dTcat'd them into a 4d nifti. I'm then running 3dClustSim. For example:
3dClustSim -athr .1 .075 .05 .01 -pthr .005 .001 -inset model-2000_permutations.nii.gz
Based on reading the docs, I'm assuming it thresholds these maps at .005 and .001 and produces the cluster-extent thresholds to limit false-positive clusters to a proportion less than the various values of athr. I think this is what I want as an empirically-derived FWE correction. Does this sound right to you?
Many thanks,
John