Leading a Rat along a Moving Virtual Reward Circle with "Rattractor", a Closed-loop Deep-Brain Stimulator.

Electrophysiological rewards in the brain have been used to affect animal behavior. We have worked on a closed-loop deep-brain stimulator named "Rattractor", which applies neural rewards in the deep brain to attract a rat toward a virtual reward circle on a flat experimental field so that its range of activity is regulated but without explicit cues. The system is unique in that the rat was not fed with one-way specific instructions on how it should locomote. Instead, the system projected a set of behavioral values that the rat should follow, and the rat tried to get comfortable by searching the virtual reward circle by itself. This paradigm composes a closed-loop cross-interaction system consisting of a rat and the device. In this work, the virtual reward circle was moved with a suitable timing for leading the rat to different places. Although the moving speed had to be low in order not to allow the rat to lose interest in the reward circle, in two trials at least, the rat was led more than 1 meter away from its the initial location. This paper describes these successful trials, and discusses the behavior of the rat in both successful and unsuccessful trials.