Hello AFNI Experts,

I recently completed a PPI analysis using Gang's set of instructions. I have a question about the output files and which sub-bucket to use in subsequent analyses at the group level. I should note that my study is within-subjects, so I am not planning on comparing two-groups. However, I do want to get a "group" average to see which brain regions correlate with the seed region for the purpose of extracting the correlation using 3dROI stats from the cluster(s) identified. I then plan to correlate these statistics with individual difference measures (I.e., personality traits) outside of AFNI.

So my question is, do I use the interaction-term beta coefficients that are outputted from 3dDecon, and average these for all of my subjects to get a group correlation map? Or would it be more preferable to do the R --> Z transformation and then do a "group" average?

Related, would 3dMean be a good idea for averaging these to get a group-level correlation map or is there a better way to identify major clusters in a within-subjects design for a PPI analysis?

Thanks,

Danny