I have a question regarding generalized PPI analysis. I will be using gPPI with a blocked experimental design that includes button press responses proceeding each task block (participant gives Likert response to an anxiety scale). These button press events obviously should be modeled in the first level analysis, but should I create and include interaction terms between events that are not of interest (e.g., these button press responses) and the seed region time series? If the answer is yes, should we also create interaction terms for motion regressors?
Lastly, are there any recommended updates to the methods shown on your info page for gPPI (https://afni.nimh.nih.gov/CD-CorrAna)?
I would appreciate any tips or advice!