afni.nimh.nih.gov

A simple weighted sum can be computed with 3dcalc, but
it will not come with any significance statistic like
3dDeconcolve would output. Using the A,B,a,b,c,d as
labels in 6 different datasets, consider:

3dcalc -a corr_A+tlrc -b corr_B+tlrc -c corr_a+tlrc \
       -d corr_b+tlrc -e corr_c+tlrc -c corr_d+tlrc \
       -expr '0.5*(B+A)-0.25*(a+b+c+d)' -prefix corr_contrast

Note: A+B is reversed just to prevent an irritating emoji...

- rick