I was simply pointing out that with lesions we have a strong one-tailed hypothesis, so we traditionally put 0.05 as the threshold and only look at one tail. If you have a two-tailed hypothesis (e.g SZ may result in some regions may showing increased activity, others decreased), you would have a two-tailed hypothesis and use 0.025 as the threshold for each tail. NiiStat is a general linear model tool, and it can analyze voxels, regions of interest and connectomes. It is agnostic regarding the source of the data.

You may also want to look at PALM
  https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/PALM
which is very similar to NiiStat, but does allow different models.