Dear spm's users,
       I found I would get different results if I did two-sample t test within a selected ROI in these two ways:
       1. I did two-simple T test on 2 groups of volumetric(2/3D image) data within a spceified ROI by applying a explicit mask(such as prefrontal cortex, come from wfu_pickaltals) in "specify 2nd level" section, and then "Estimate" and "Results";
       2. I did the same two-simple T test but without applying any explicit masks in "specify 2nd level" section, but did a ROI analysis in "Results" section.
       I found these two different ways would lead to different results. Anybody has any suggestions on this issue?
      Thank you! Best regards!