Hi!
Apologies in advance if this is a simple question that's already been answered. I tried looking in the archive but couldn't find a straightforward answer.
I have an fMRI experiment with 20 participants and several repeated conditions (familiar drug cues, familiar neutral cues, novel drug cues, novel neutral cues), and I've run the lower-level analyses. I've tested fam drug-fam neut to get at effect of drug in familiar stimuli; nov drug - nov neut to get at effect of drug in novel stimuli; fam drug + fam neut - nov drug+nov neut to look at overall effect of familiarity; and I have each condition alone (there is a baseline condition that I'm not modeling). I'm just not sure how to set up the group analyses to test the effect of drug (drug-neutral), the effect of familiarity (fam-novel), and the interaction. It's the interaction and what the inputs and contrasts/F tests are that is really confusing me. Thanks for taking the time to read this and for any help you can provide.
Best,
Gregg
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