This manual is intended to provide a guide for anyone interested in linking together the Tobii 750 eyetracker and a SynAmps II Neuroscan system. The funding for this project was provided by an R03 Grant awarded to the PI, Mandy Maguire. As specified in the original grant, the goal was to create an integrated system that (1) linked eye tracking and EEG in real-time and (2) could allow for stimulus presentation contingent on eye gaze, such that looking to one specific point on the screen (or away from the screen) would dictate what would come up next. This was particularly important for us as a way to show “attention getting” stimuli for infants and young children completing visual EEG studies. This manual summarizes important aspects of our study, with specifics about the software and hardware needed to the interlocked system, written with the hope that it will provide a brief but useful introduction for others who may wish to adopt this technique.
This manual details how to configure the Tobii 750 eye-tracker to work with E-Prime software for real-time EEG and gaze data collection. It covers port configuration, timing adjustments, defining regions of interest (ROIs), and sending triggers. The setup allows stimulus presentation to be contingent on eye gaze, useful for studies involving infants and children. Timing corrections are essential to achieve ~1ms precision in data synchronization.
The document includes specific steps for defining ROIs using textboxes, handling processing delays, and adjusting trigger timestamps in Neuroscan’s .CNT files to account for screen refresh rates and eye-tracker lag times.
The Tobii 750 eye-tracker is used in this setup.
The eye-tracker monitor’s refresh rate is 59Hz (or ~1 screen refresh every 16.66ms).
There is a processing delay of ~3ms from when the eye-tracker registers eye-contact to when it sends a trigger to Neuroscan.