Hello FSL experts,
I need to enter a covariate (past alcohol use) into a group mean FEAT analysis and am a little confused as exactly how to do so. More specifically, I understand that I need to add an additional EV with each participant's scores on our covariate-of-interest, but I am unsure how to setup the contrasts and to interpret the subsequent activation maps. The website says that I should have two contrasts:
-Contrast 1 assigns a '1' value to my group-weights EV and a '0' to the covariate EV
-Contrast 2 flips these values
My question is, which of these contrasts is showing me activation controlling for the covariate?
Additionally, how is this different from adding a regressor-of-interest, in which I want to see areas of brain activation that correspond to changes in the regressor?
I hope my questions are clear. Please let me know if any clarification is necessary and thank you so much for your valuable time.
Cheers,
Dave
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