Problem sending trigger signals with E-Prime 3

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1

Hello,
I’ve been posting questions on this forum and so far I am extremely grateful for prompt and on-point responses.

We are currently designing an experiment using E-Prime 3 and would like to send trigger signals to our MEG system using StimTracker Quad and m-pod. We followed the instruction on Cedrus website (Using StimTracker with E-Prime 3) and successfully observed 7 trigger patterns using a 3 bit binary scheme (excludes 000). We are now attempting to modify the code so that we can distinguish 48 stimuli by combination of two 3 bit binary trigger signals (as illustrated in the attached image).

new trigger signal coding scheme
new trigger signal coding scheme719×443 51.8 KB

We were wondering which part of the code we could modify to implement the new trigger signal scheme.
Additionally, if anyone has better solutions we would like to hear them as well. One limitation is that we only have 3 trigger channels in our MEG system.

Thank you in advance.

Jion

2

Your approach is clever. Unless I am misunderstanding the question, it sounds like you should be using the function that sends the pulse twice: the first time with the first 3 bits and the second time with the second 3 bits.

I suggest you leave some time between them, say at least 5 or 10ms. Otherwise it might become difficult to interpret the data when doing the analysis.