Hi Rick,

Thanks for your answer. I will remove the -regress_use_stim_files and -regress_stim_types parameters.

Each trial starts with a cross for 500ms, then there is a stimulus composed of two images presented one after another for 500ms each, and then the subject has 2s to make a decision. After that, there are "irrelevant" (for this correct/incorrect analysis) stimuli: the subject is asked to rate its confidence by pressing a button 1-4 within 2s, then there is a random delay between 2.5-3s, then the subject sees a feedback stimulus about that decision for 2s, is asked to make a second decision within other 2s, and finally there is another random delay of 2.5-3s. It would be great to model these other stimuli as well, as they are related to the main decision-making process. How can I model multiple ones at once? I have stim_files saying which trials are low vs. high confident, or in which trials the second decision is different from the first one.

Thanks,
Davide