Development of virtual reality environment for tracking rat behavior

Several virtual reality (VR) studies have demonstrated the feasibility of animals interacting with virtual environment (VE) by using reward schemes and visual cues to study attention processes, spatial memory, and executive functions. This study aimed to develop a rat behavior testing environment with immersive VE which allowed the animal to respond and interact with stimuli in a limited space. We integrated back-projected dome screen to display visual stimuli and a motion detection subsystem for sensing the animal's intention. In our self-designed animal cage, the front hemisphere screen connected the outer cage in one-degree-of-freedom for pitch rotating to ensure the animal was constrained at optimal view point during the experiment. The intentions of the animal were detected by body position sensing device, which sent rotation and yaw angles via TCP/IP transmission to alter VR generation. A camera was mounted behind and slightly above the animal, allowing the experimenter to observe the locomotion of a rat and to synchronize the recording of animal activity. Validation tests of animal behaviors on the developed VR system were observed from animal motion and display of VR stimulation. The establishment of immersive VE serves as the initial step for future study of correlating spatial learning and recording of brain neural activity in a novel experiment protocol.