Hi, I have a question regarding a specific set of contrasts I'd like run.
Essentially I have three factors (Subject (22 total), Region (3 levels),
Side (2 levels). I'd like to set up the following contrasts in SPM:
1. (F) Main effect of region: zeros (1,22) -1 0 1 0 0 -.5 0 .5 -.5 0 .5
2. (F) Main effect of side: zeros (1,22) 0 0 0 1 -1 ? ? ? ? ? ?
3. (F) Interaction of region by side: zeros (1,22) ? ? ? ? ? ? ? ? ? ? ?
4. (T) Region 1 - (Region 2, 3): zeros (1,22) ? ? ? ? ? ? ? ? ? ? ?
5. (T) Region 2 - (Region 1, 3): zeros (1,22) ? ? ? ? ? ? ? ? ? ? ?
6. (T) Region 3 - (Region 1, 2): zeros (1,22) ? ? ? ? ? ? ? ? ? ? ?
7. (T) Side Right - Side Left: zeros (1,22) 0 0 0 1 -1 ? ? ? ? ? ?
8. (T) Side Right - Side Left: zeros (1,22) 0 0 0 -1 1 ? ? ? ? ? ?
I'm most confused about numbers 4, 5, 6 (how to contrast one Region against
the other two) and also how to represent the interaction terms. I would
greatly appreciate any assistance with this setup. Thanks for your time,
Sincerely,
Lucina Uddin
|