Hello Dr. McLaren,

I was trying to implement gPPI on our data. So far it has been great.

In our data, we have 3 sessions, each session with a 2x2 design plus regressors for the time derivatives, motion parameters and outliers (from ART).

As you mentioned in the previous threads, I understand for P.Task I would only need to include the 4 regressors. Since they have the same names across sessions, I wrote:

P.Tasks={'1' 'hit_high' 'hit_low' 'miss_high' 'miss_low'}

Which worked out fine. But for some participants, they could miss one regressors in one session. If that happened, the regressor was omitted in our first level design for that session and first level contrasts were modified accordingly. For PPPI, do I need to set P.Task= {'0', ...} and manually add _run1 _run2 for the regressor names to generate the right contrasts? 

Thanks for the help!
LT