Insert data marker into questionnaire (case 5183)

Hello,

I have yet to find a satisfactory answer, but how and where do I request MediaLab to send a data marker when running an EEG experiment? I am composing my experimental protocol as a "questionnaire", and would like the onset of a stimulus (ie. music or sound clip) to be marked in the EEG data being recorded (using Emotiv TestBench and Eltima Virtual Serial Port to connect). Additionlly, how do I label each data marker so that we can identify the stimuli in the EEG output? For example, can the onset of video 1 have a different label from video 2, 3 and 4? Can someone please help??? Thank you!

Hi,

I think what you're looking to do is send a signal to external hardware, and that is usually accomplished with the ttl parameter.

In the parameter box of an image, audio or video display, you can include a ttl parameter as follows:

<4:888:10>

This ttl command is instructing at the onset of the questionnaire item the signal "4" should be sent to port "888" for "10" ms.

The signal (in this case, 4) is up to you. If you want each signal to be unique, use a unique number there for each questionnaire item (e.g., video). The port is important, you need to know the port address of the virtual serial port has assigned to the TestBench. Be sure you're entering the decimal port address, not the hex port address. The duration you should send the signal depends more on the sensitivity of the device receiving the signal. Be sure to consult the TestBench's manual to understand how it receives markers.

If you're having a little trouble, there is a TTL I/O test utility that can be found in the following utilities folder: C:\MediaLab\Utilities\TTL\IOTest.exe

Let me know if that works for you.