The TGR uses an Any-maze special version to manage temperature zones, track the animal and record/analyse the results.
Optimal tracking is reached by using an IR-transparent wall an IR-sensitive camera, an IR-Visible illumination and an example of the outcome can be seen at the following link: https://www.youtube.com/watch?v=PaTwDK6uJp0&t=62s
Learn more on Thermal Gradient Ring by Ugo Basile.