Few ideas excite the imagination more than virtual reality. We humans use virtual reality for training, entertaining, and even education, but we can also use it to study human and animal behavior. Adaptive behavior, or the ability to adjust to new situations, is influenced by what we see, hear, and experience in our environment; unfortunately, for this reason, it is difficult to isolate the possible stimuli that affect it. The authors of this recently published PLOS ONE paper developed a virtual reality environment to try to isolate and measure the impact of visual and sound cues on rats navigating through a virtual space.
The virtual reality navigation test is based on an experiment called the Morris Water Maze, a standard lab test where a rat swims through water using visual cues on the walls to navigate. The virtual version uses a 14 square-foot room with visual cues projected on each wall and sounds from 4 sides (pictured above). The rat is at the center of the room, wearing a harness (pictured on the right) on a spherical treadmill placed on a three-foot circular table.
Before beginning the navigation tasks, researchers trained nine male rats to move in virtual reality. The rat started from one of 4 random start locations, facing the wall (see video below). The northeast quadrant of the space was designated as the ‘reward zone,’ indicated by a white dot. Upon entry to this zone, the rat was rewarded with sugar water (if only all video games worked this way).
After training, the researchers tested each rat’s ability to navigate to the reward zone using one of three cues: audiovisual, visual, or auditory. Once the rat found the reward zone, a 2-second blackout period was initiated, and then the rat was ‘moved’ back to one of the 4 random start locations. The video below shows the visual cue test.
Scientists found that rats can learn to navigate to an unmarked location based on visual cues—with a moderate amount of training. However, the rats were unable to use the auditory cues to navigate to the reward zone, and instead moved in circles to try to locate it.
Although the rat’s harness may look a little funny, it is a relatively noninvasive test, and since the animal is not in water, like in the Morris Water Maze test, it is easier to combine this test with tools to measure neural and physical variables in the task. Additionally, the virtual maze may contribute to new methodology evaluating the underlying factors in adaptive behavior, specifically because no other cues besides the audiovisual, visual, and auditory defined the spatial location of reward, something that is difficult to achieve in the real world. Despite humans not yet understanding what virtual reality means to us, we can already use it to better understand animal learning and behavior.
Citation: Cushman JD, Aharoni DB, Willers B, Ravassard P, Kees A, et al. (2013) Multisensory Control of Multimodal Behavior: Do the Legs Know What the Tongue Is Doing? PLoS ONE 8(11): e80465. doi:10.1371/journal.pone.0080465
Image 1: doi:10.1371/journal.pone.0080465
Image 2: doi:10.1371/journal.pone.0080465
Video 1: doi:10.1371/journal.pone.0080465
Video 2: doi:10.1371/journal.pone.0080465