Hello,
I want to have a map of a contrast between two conditions at the
single-subject level. I tried two ways to do that, which resulted in exactly the same thing, which perhaps is good news but this confuses me. I did expect different results.
Option 1: gltsym in 3ddeconvolve
-gltsym 'SYM: +C1 -C2' -glt_label 1 'Contrast_map1' \
Option 2: 3dcalc
(Assuming for the example C1 is sub-brick 2 and C2 is sub-brick 4).
3dcalc 'func+orig[2]' -b 'func+orig[4]' -expr 'a - b' -prefix Contrast_map2
Option 2 is a difference between t-statistics, while Option 1 a t-statistic of a difference.
1. Are they expected to have different outputs? If so - in what way? And what should I use?
2. Does it make sense that the contrast map I get is the same no matter what option I use?