A former supervisor once suggested to me to add an event which starts at the last possible moment. If you put 0, SPM inserts an event starting at time zero. But if your scan is, for example, 600 seconds long, add an event at 599.9 seconds. Then you basically get a regressor full of zeros. 

On 12 June 2014 22:36, Pilar Archila-Suerte <[log in to unmask]> wrote:

SPM users, 

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.