I'm performing an fMRI analysis for my master thesis using SPM and I've never worked with fMRI data before. I've succesuffy perform first level analysis but came to an obstacle. Study design consists of 2 sessions, one right after another. In the first session, subjects performed control MIST task, while in the second session the stressor was presented during the MIST task. So the first session was control session and the second session was stress session. There were two conditions in both sessions; feedback (when pariticpants received feedback) VS. rest (everything else/baseline). I was first interested in contrast between feedback and rest which shows us activation that was purely result of the feedback in both sessions. I've succesfully defined T-contrast and already observed the effect of feedback. Then i came to a problem; I want to compare the effect of feedback between control session and stress session, so I could see if there was a larger activation after feedback in stress session in comparison to control session. I've searched a lot but didn't find anything helpful. So my question is, at which point i can compare first session with the second session, and how can i do that? Should that just be another contrast like feedback vs. rest, so session1 vs. session2? Or this is the matter of second level analysis? Thanks a lot for any kind of suggestions and help!