Hi experts,
I want to detect voxels that are both more responsive to A than B and more responsive to A than C at the population level (RFX). Seems like the straight forward FSL way for doing this is to use 'contrast masking' at the first level (mask A-B with A-C) and then use FLAME for the second level. I want to use FDR, which makes things more complicated, since it can't control for the FDR of both contrasts, but only for the contrast being masked (A-B).
I couldn't find a way to control for both, so I decided to use (Nichols et al 2005)'s minimum statistic method (MS/CN) instead. For each subject I created a new cope image comprised of the minimum value of each voxel between cope1 (A-B) and cope2(A-C). I couldn't find a reasonable method for assessing the varcope and the tdof of my conjugated contrast, so instead I used Simple OLS and for each voxel performed a one sample t test on that voxel's value.
I have two questions:
1. Does this approach sound reasonable?
2. Is there a better way? (specifically - is there a way to evaluate the varcope and tdof of the conjugated contrast?)
Many thanks,
- Matan
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