I'm running a group study.
I have 2 event types, A and B, from which I obtain 2 contrasts (cA, cB) at the single subject stage (i.e. 1st level analysis).
Assuming that at the group level stage (i.e. 2nd level analysis) I want to show areas that are activated both by event A AND by event B, how should I proceed?
Is there a specific design at the 2nd level that I can use for this purpose? Or can I use some kind of computation with ImCalc, like cA*cB with a certain thresholding or scaling factor? Or the correct way is to generate a t-contrast at the 1st level for the logical AND of A and B (how?) and then run a t-test on this contrast at the 2nd level?
Thank you in advance for you answer,