Hi,
I'm finding some apparent contradictions between my AFNI contrast effects and my standardized activity plots for a voxel of interest. and I just wanted to see if my reasoning was correct. First off, I have 3 tasks in my experiment, lets call them A, B, C. A is a control tasks and B & C are memory tasks. So I wanted to test a contrast for a Mem VS Control using the following contrast: -2 1 1. Now according to this contrast I obtain a t= -3.7 for my pfc voxel of interest, and so I interpretted it as being more active during my control task (because of it's negative value)...this seems to be the case for other voxels that don't give me the following issue. However, when I extract the standardized activity value for this voxel and plot a bar graph of it I see that it has positive standardized values for B & C and a negative standardized value for A..suggesting that this region is less active during the control task versus the memory tasks. Now, if do this for other voxels I get the opposit bar graph result (more activity in A vs. B &C)..this latter case makes sense to me since it seems consistent with my AFNI interpretation that this region is more active in the control. Why do I get the opposite effect for the initial pfc voxel I mentioned when it is the result from the same contrast effect? Thanks for your help. N