Hi Gang,
Thank you very much for taking the time to read my question and think about it, I really appreciate it. I would say that the Cue5-Cue0 contrast would be the most relevant to our hypothesis, since it's likely the strongest contrast (high reward vs no reward). We would probably be interested in doing this same analysis with a 0.5*Cue5 +0.5*Cue1 -1*Cue0 contrast (so, some reward vs. no reward) and see what that looks like as well. But, if that is too complicated, we would be ok with just Cue5-Cue0.
Thank you once again!! We've been kinda stumped with this analysis for a while.