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Help! Trigger signal was not displayed in SEEG experiment

Psychopy version: 2021.1.4-win64 system
Windows system: win10

Hello, everyone, I am going to collect SEEG data using a 256-Intracranial EEG system (Nihon Kohden system). And my experimental tasks was already designed in PsychoPy coder interface. Communication between the Intracranial EEG system and Psychopy is via a 25-pin parallel port cable.

My problem is that the trigger signal used to mark the experimental process cannot be displayed on the intracranial EEG.But the puzzling thing is that my experimental program runs normally without errors.

Moreover, My experimental procedures runs very well on a common EEG system such as Neuroscan, and trigger signals can also be seen on the EEG.The computer operating system used to run the procedures is Win7.

In addition, I know that common EEG systems such as neuroscan and the intracranial EEG system I use both send and receive trigger signals through a 25-pin parallel cable, and the difference in principle is as follows.

After receiving the trigger signal, the neuroscan system presents the signal with the marker number written in the experimental program, but the intracranial EEG system generates a pulse signal for presentation after receiving the signal, and the pulse is shown in the figure as follows

Very much looking forward to getting everyone’s ideas and suggestions, thank you sincerely!

Best wishes to all.
Melody1.

Hi Melody,

I’m not sure I understand you correctly. You say that:

My problem is that the trigger signal used to mark the experimental process cannot be displayed on the intracranial EEG.

but also that:

(…) the intracranial EEG system generates a pulse signal for presentation after receiving the signal, and the pulse is shown in the figure as follows

My understanding is that both your EEG and intracranial EEG receive the trigger but save it differently. The sEEG seems to store trigger information as a separate channel. Please verify if this is the case. If it is - then you only need a short script to convert trigger channel timeseries into your preferred marker format (for example EEG.event field, because your figure suggests you are using EEGLAB).

Hello, mmagnuski

Yes, as you said, both my EEG and intracranial EEG receive the trigger but save it differently. The sEEG seems to store trigger information as a separate channel, and EEG system stores signals on all channels.

Now, my problem has been solved, I switched to a computer to run the experimental program, and then the pulse signal appeared on the intracranial EEG.

But I still have some doubts: about the difference between the computer used for the first two failed tests and the lab computer used for our successful tests, all I can think of is the difference in operating system, one is Win7 and the other is Win10, could there be other differences that lead to different results of transmitting the trigger signal?

Best wishes to you.
Melody.

Sorry, but I still may not understand what the problem was. Originally, before switching to another computer - how was the trigger recorded in the sEEG signal? Was the trigger sEEG channel empty then?

But I still have some doubts: about the difference between the computer used for the first two failed tests and the lab computer used for our successful tests, all I can think of is the difference in operating system, one is Win7 and the other is Win10, could there be other differences that lead to different results of transmitting the trigger signal?

I don’t think the difference was in transmitting the trigger. If the trigger was previously read as a separate channel and now as events, then the difference is most likely either in the software used for recording or reading the signal. Such behavior could change between versions of software you use. For example, if you read and visualise the data in EEGLAB (as I suspect from the image you attached), a different computer might have different version of EEGLAB installed - one that automatically parses the trigger channel into events.

Hello,mmagnuski
Before switching to another computer - the trigger did not record in the sEEG signal,and my experimental procedure ran well ,That is to say , my trigger code is correct, while there is a problem with the transfer of the trigger through the parallel cable, possibly due to poor contact with the parallel cable, or possibly due to a problem with the parallel socket of the computer on the lab side, resulting in the inability to transfer the trigger to the sEEG system, and then there is no way to display it in the SEEG signal.

For “I don’t think the difference was in transmitting the trigger.”,I strongly agree with you, indeed the computer’s operating system is not directly related to the transmission of the trigger, it does not affect whether the trigger can be recorded by the sEEG system

Best,
Melody.