Dear highly respected SPM community,
I need your advice and expertise in helping me to understand how to set up correctly a parametric modulation design.
So, I have a normal multi-trial design in which each trial starts with a Cue period, then ISI, then Rating period in which participants have to choos on a likert scale one of several (5) distinct bidding options: $0, $15, $30, $45, $60 (i.e. the rating variable is categorical, non continuous).
Now, what I'm wish to do (and I never did before) , is to check how the bidding choices of participants affect/modualte the neural activity during the cue periods. Therefore, I think the best thing to do is to include the rating choices as a parametric modulation on a trial by trial basis (i.e. Define it in the 1st level analysis).
So, my question is the following. How exactly do I do that? What's the best way? And whether you also think there is an additional way I can check this.
Thank you so so much for taking the time to consider my question.
Wish you all a wonderful week.
Claudia
PhD student
Munich
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