5 button fMRI response pad?


My lab is running an fMRI experiment and we need to somehow have 5 response options. Our centre uses a Lumina LSC-400B controller and I noticed it only has lights for 4 buttons (plus scanner trigger).

I’m wondering, is it possible to record 5 response types? If so, has anyone come up with a solution how to? Cedrus doesn’t have 5 button response pads and told me that even if we found one, that it wouldn’t be supported.

Alas, the present LSC-400B is limited to four buttons, plus a fifth input for the scanner trigger.