How can I record visual ERPs using TMSi SAGA?

You need to install the stand-alone version of Psychopy and use the USB-TTL module to record visual ERPs with SAGA.

Using stand-alone Psychopy and TMSi SAGA, you can design an auditory or visual experiment to record ERPs. Psychopy is a free software commonly used to create behavioral and psychology experiments. The stand-alone version of Psychopy has a graphical user interface which is an intuitive way of creating such experiments, especially if you don’t prefer coding. Below, the instructions to add the USB-TTL module to your experiment are described. This way, you can make sure that the events are registered simultaneously with your EEG data.

1. Download the stand-alone version of Psychopy here.
2. Make sure the USB-TTL module is connected to the experiment PC and to TRIGGER input of SAGA Docking Station.
   Note: please refer to our Knowledge Base article about configuring the USB-TTL module to make sure the timing is accurate.
3. In Psychopy's main window, select ‘Serial Out’ from the righthand side, under the I/O components.
   
   
4. The properties page will pop up. Here you can define the conditions or the times at which an event will be registered on the TRIGGER channel. As an example, the start and end time of the target image (visual ERPs) can be given (see below).
   
   
   1. Most importantly, the COM port number should be correctly specified. To identify the correct port number please read this Knowledge Base article.
   2. Furthermore, the values to be registered in the TRIGGER channel should be specified. Please note you should write the desired value in hexadecimal system. For example, if the desired value is 64, you need to put 40 as this is the hexadecimal representation of number 64 (see screenshot above).
5. Lastly, switch to the ‘Hardware’ tab and check that the information matches with the USB-TTL module. This information can be found in Windows by opening the ‘Device Manager’ and then the Ports (COM & LPT) section.