Hey Andrew,

Thank you for your quick and detailed reply.

Based on your suggestions I have contructed the 48x15 design matrix (included as attachement), contrasts and exchange blocks. As a sanity check, could you confirm that this is correct?

The contrasts for the interaction effect would be [0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 ] or [0 0 -1 0 0 0 0 0 0 0 0 0 0 0 0 ]. What is the exact difference between these two versions of the contrast?

The exhange blocks would be [1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12]

At a range of thresholds there appear to be no changes for the interaction effect with a lower p value than 0.2. 

I had an additional question regarding contrasts and network analysis, given your expertise. Is there a way to look at (significant) changes in modularity, rich club coefficient or participation coefficient for the interaction of music and drug specifically? 

Thank you so much for all your help.

Sincerely,

David