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Dear all, I am currently analyzing a study that I have modeled using the three-level approach fsl recommends (session, subject, group) - where a session in this case is simply a run of the same fMRI experiment- and now I would like to run a PPI analyzes in it using a seed obtained from a group effect. My question regards at what level one should set up the PPI in this case. It seems to me that, for PPI analyzes purposes, one should ideally run it at the subject level (2nd), rather than at the session level (1st): given one is interested in detecting correlations in activity between brain areas dependent on task context, those correlations would tend to be less reliable if they were estimated based on shorter time epochs (i.e., run/session) than if they were estimated based on a longer time epoch (i.e., the entire fMRI session), correct? If that is indeed the case (where the PPI setup should be done at the subject level rather than at the session level, despite the fact the experiment was originally modeled beginning at the session level)- which 'filtered_func_data' file should I use to extract the time course (using the group effect seed) from? Currently, having adopted a fixed-effects model in the intermediate level for each subject, I don't have a 'filtered_func_data' for each subject as a result- and have instead one 'filtered_func_data' for each cope of interest (feat directory) within each subject's .gfeat directory. . . Would that (the 'filtered_func_data' from the cope of interest for a given subject) be the one to use. . . ? Thanks much for your feedback, Regina