[Eeglablist] EEGLAB/MITSAR compatibility issues

Kasper Eskelund kaes at dtu.dk
Thu Jul 3 11:38:37 PDT 2014

Dear all,

I am working on setting up a MITSAR 201 system for ERP studies, but have difficulties in getting triggers/markers right as events in EEGLAB. Does anybody know how to produce EEGLAB compatible ERP recordings with MITSAR systems?

When sending a trigger/marker through the serial port, it indeed shows up in EEGLAB, but 1) not as a single event but rather a burst of markers, 2) the event labels do not correspond to the values sent (integers transfer to decimals (0.3841, 0.3611, etc.)), 3) EEGLAB detects the events (they show up in the EEG structure), but when epoching from the GUI, EEGLAB can’t find them.

Thus, I hope that someone in the community using a MITSAR system could possibly provide insights on how to set up the system.

Currently, I use MITSAR's WinEEG software for data acquisition. This accepts triggers send to the serial port. The WinEEG pacakge seems to be tailored to work with MITSAR’s stimulus software PSYTASK. But it should in principle be able to handle serial port triggers from other systems. The trigger is send as serial port data. I also worked with high/low settings of the DTR, CTS and RTS pins, but WinEEG does not recognize these signals.

I use Psychtoolbox within MATLAB for stimulus presentation, writing trigger signals to the serial port with the IOPort command. I could revert to using PSYTASK, but it is somewhat restricted compared to Psychtoolbox/MATLAB.

Stimulus presentation and EEG data recording are performed by two separate Windows 7 PCs.

I hope someone in the community may have worked with a comparable system and can give a few hints, as to get things right.


Kasper Eskelund
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