Exclude bad trials with "Combine stim/response"

Discussions
1

Hi,

I am new with Brainstorm and I’m having a hard time figuring how to exclude trials for which the participants gave an incorrect response.

I have a stimulus marker (999) and two response markers, S250 (incorrect response) and S251 (correct response).

Is there a way to remove those bad trials with the function “Combine stim/response” without removing the good trials?

I tried many scripts but the last one I tried (S250_999S250, extend, 999, S250) seemed to remove the bad trials, but also some good trials since it searched from the stimulus (999) until it found a response S250, even tough there was another response S251 in between. Is there a way to make it search from the response S250 until the stimulus 999, in order to avoid to exclude the good trials (S251)?

Thank you,

Edith

2

I forgot to mention, the stimulus is presented until a response is made, so there is no fixed stimulus presentation time.

3

Hello Edith,

If I understand correctly, what you want to do follows exactly what the example described in the process does, with your stimulus ( A ) being 999, your 1st response ( B ) being S250 and your 2nd response ( C ) being S251. So try the following:

999_999S250, S250_999S250 , 999 , S250
999_999S251, S251_999S251 , 999 , S251

Make sure to adjust the maximum delay between events appropriately.

I hope this helps,
Martin

1 Like
4

Hi Martin,

Thank you very much!

Edith