I have some fMRI data where participants were asked to press a left or right button when they heard a word that matched 1 of 2 images on the projector screen. I have coded correct and incorrect responses. For some participants in some of the conditions, I have 0 incorrect responses. However, I still have to enter the condition in the first-level batch with no vectors. SPM will not accept a condition with an empty field (i.e.., with-no-vectors). What would be the best way to get around this issue? just enter a "0" as the vector? or make up an impossible number in my data like 100000?

Any help would be greatly appreciated.

Pilar A.