Hi Gang,
Thank you, this makes sense.
I have a followup question, is there a way to code using 3dMVM a "slope" across three contrasts. For example, if I have two groups and three conditions (A, B, C), is there a way to test whether the "slope" between the two groups differ at any given voxel. Basically the slope would be a relationship computed between betas from A, B, and C, for example, A > B > C, or C > B > A. I isn't like the example that we've been going over in which we're interested in both A > B, and B > C, but something more like all three conditions in a single contrast with an expected relation between then (i.e., B lying numerically between A and C,with either A > C or C > A, for example).
Sorry if this doesn't make sense. Please let me know if doesn't and I'll try to be more clear.
Thank you,
Matthew