Hi, Mengxing-
Well, you can use 3dClusterize to threshold more easily than with 3dmerge/3dclust, probably:
[
afni.nimh.nih.gov]
There, you can use either voxelwise p or statistic value, along with cluster volume. For a code example using it on an actual dataset with 3dClustSim and , you can see here:
[
afni.nimh.nih.gov]
I haven't looked at using this *specifically* with 3dFDR output or whatever you are using, but it should be an easier place to start than 3dclust/3dmerge.
--pt