Dear FSL experts,
Thanks for your advice about contrast masking on the second level. I have done it with good effect and have been able to mask the contrast A>B with A>O and B>O, thereby assuring that only the voxels greater than 0 show up in the A>B contrast.
One last question--regarding conjunction analyses--
I am looking at two conditions A>0 (baseline) and B>0 (baseline) -- with the desire to know what areas are similarly active.
On the second level, I set up 2 EVs--(1) A and (2) B and do contrasts for the group means for A and for B. Then I contrast masked (voxels >0) A with B and then B with A. I sometimes get different results for the A masked with B and the B masked with A.
Can you explain how that happens and what that means? Not sure how to interpret it as I thought conjunction means only the voxels that are common to both contrasts will be shown.
Thanks so much for your help.
Two months to my defense and I am winding down the analyses and writing now.
Much appreciation-
Nan Wise
Rutgers-Cognitive Neuroscience
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