Collecting Response Brief Stim

I need to present a stimulus for 150ms and then collect response. I can’t collect response on stim screen bc it is too brief. I have inserted a blank collect response screen, but this creates the following problem. The blank screen is not where I have assigned responses as correct or incorrect, thus any keypress recorded here will not be labeled as a correct or incorrect trial.
I think that I need a way to use code values to accomplish this. However I need some advice. or even better a demo that uses brief presentation and collects a response after the stimulus is removed from the screen.

What you can do is present the stimulus again on the collect response screen, however make sure you set it to be presented offscreen. This way you can set incorrect and correct responses, but the subject won’t see anything.