Eye tracking
The CBU currently has 4 eye trackers. One is in the MEG lab, one in the MRI scanner, and we have two separate eye trackers for use in other locations. All eye trackers are manufactured by SMI and use the same SMI software for controlling the eye tracking hardware, for stimulus presentation and for analysis of the eye tracking data. In addition, all trackers can also be used with E-Prime and other custom experiment presentation software.
Since spring 2013 we now have two additional eye trackers in the CALM lab: one Tobii remote tracker and one head mounted eye tracker.
Eye tracking fundamentals
Fundamental information about eye tracking technology
eyemovementresearch.com - A very good online resource for anything related to eye tracking
Eye trackers at the CBU
MEG eye tracker - 250 hz tracker.
MRI eye tracker - 50 hz tracker, similar to MEG setup.
RED eye tracker - Remote system for behavioural tests.
Hi-speed eye tracker - High-speed tracking for more demanding behavioural tests.
Using eye trackers
Eye tracking is not as easy as it might look, and there's also quite a bit of variability between subjects. Most problems can be solved and with the vast majority of people you should be able to acquire decent quality eye tracking data.
Instructions for specific software packages
The SMI eye trackers come with their own stimulus presentation software, Experiment Center, and their own analyses tool, BeGaze. Experiments designed and executed in Experiment Center are very easy to analyse in BeGaze, as everything is recognised automatically. The trade-off is that Experiment Center only allows fairly simplistic experimental designs.
If you want to use other experiment software, you will need to customise your scripts.
Eye tracking with Experiment Center
Eye tracking with Matlab (Cogent / Psychtoolbox)
Eye tracking calibration with Matlab in the MRI scanner
Data Analysis
The eye tracking data can be analysed very easily with the SMI software package BeGaze. This will plot raw data, gaze paths, dwell times, heatmaps etc. at the click of a mouse. It cannot do statistical analyses, though, and you will have to export the data from BeGaze for that. BeGaze will allow you to create areas of interest, even moving ones in videos, and calculate total dwell time for all your AOI's.