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Dear experts, I am running an fMRI experiment in which I have four conditions: two main conditions (condition A and condition B) and two respective control conditions (condition Acontrol and condition Bcontrol). I would like to create a map showing significantly greater activity for condition A relative to condition B, after subtracting out the activity for the respective control conditions. In other words, I would like to perform the following contrast: (condition A - condition A control) - (condition B - condition B control) Then I would like to have a map that shows the reverse contrast too:(condition B - condition B control) - (condition A - condition A control).
How do I do that?To obtain the first map: (condition A - condition A control) - (condition B - condition B control) I have tried with the mergecontrasts-sess function with the -conjunction flag and the OR option as detailed below: mergecontrasts-sess -mergedcontrast conjres -conjunction or -analysis analysisname -map sig -space sph -isxavg fixed -contrast Contrast1 2 pos 0 -contrast Contrast 2 pos 0 -s sessionsfMRI/Sub01/bold -hemi lh
where Contrast1= (condition A - condition A control) and Contrast2= (condition B - condition B control) however the map I get is exactly the same as (condition A - condition A control), as if subtracting out Contrast 2 had no impact on the map.
Thanks,
Paula