Hi Eugene,
thank you for the link; but could you please clarify one issue for us:
In the practical it says that to ensure no "reverse activations" one should use Z>0 masking on BOTH A and B. So, for the contrast A-B, you would only include voxels if A>0 AND B>0 (and of course to be significant A-B>0). Doesn't this mean that if a voxel had a value of 1000 in A, and a value of -1 in B it would get masked out, leading us to miss it (declaring it a reverse activation)?
Would an alternative be to create a mask where you force "A + B > 0" ? With this mask you would not be requiring A and B to be jointly > 0 but the more B is negative, the more A has to be positive to "compensate" therefore avoiding reverse activations.
Just a thought..
cheers
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