You would just run mkcontrast-sess, eg, if your four conditions are ordered condA, condAcontrol, condB, condBcont, then mkcontrast-sess -analysis analysis -contrast contrastname -a 1 -c 2 -c 3 -a 4 If you want it reversed, then just reverse the a's and c's
On 10/23/2020 4:39 AM, Paula Maldonado wrote: > External Email - Use Caution > > 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 > > > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
