Fig. 2

Behavioral task chamber and parameter definitions used for commutator control algorithm. a The head position is defined by the mid-point between LEDs, and the head direction is defined by the angle between positive y axis of the video image and rostro-caudal axis of the animal. The underlying polygon indicates the shape of the behavioral chamber. Open circles indicate the positions of visual cues. The diamond and filled circle indicate reward and start nosepoke hole position, respectively. R and G indicate red and green LEDs, respectively. Dashed line indicates a virtual rectangle of the starting position. b The flowchart shows how the commutator control algorithm works. After trial initiation, the instantaneous head direction is acquired as soon as the mouse leaves the starting position. When the mouse comes back into the starting position, the trajectory is analyzed to generate total rotation number (TRN) which is used to actuate subsequent motor drive. For more details please see Methods