A virtual reality arena for flies.
If you’re a Star Trek fan, you’re well acquainted with the concept of the holodeck, an immersive virtual reality environment in which characters can virtually interact with any setting. You may also have had the thought, “Wouldn’t it be cool if someone made one of those for fish?” No? Well, that’s the thought that inspired researchers at the University of Freiburg. Professor of Biology Dr. Andrew Straw, along with Dr. Kristin Tessmar-Raible of the Max F. Perutz Laboratories and an international team of scientists, created a holodeck for the purpose of studying animal behavior in a virtual environment.
Researchers have been trying to find out more about how animals learn spatial cognition, and Dr. Straw and his team turned to sci-fi to find the answers.
“Until now, we have envied an invention from the world of science fiction: a holodeck like they have in Star Trek,” he said. “Something like the holodeck from Star Trek would enable key experiments in which we could artificially decouple an animal’s movement from its perception.”
A virtual reality environment for fish.
The holodeck system was constructed for flies, mice and fish, animals commonly used in neurobiology and behavior research. The goal was to separate movement from sensation, two processes that are linked in the brains of humans and animals. The 3D virtual environments included images such as vertical columns, plants, and even space invaders. Several high-speed cameras tracked and recorded the exact 3D position of each animal in the virtual environment, and a computer program recorded the animals’ movements within milliseconds and projected constantly updated videos on the walls.
“We created an immersive, 3-D virtual reality in which the animals could move freely, because we wanted our visual scenery to tie in naturally with the animal’s own action-perception cycle,” said Dr. Straw.
If you’re delighted by the idea of a fish swimming in a swarm of space invaders, you’re not alone, but the researchers gleaned valuable knowledge from that particular experiment – the computer-controlled space invaders were programmed to recognize the fish as one of them, and the fish’s behavior was, in turn, influenced by the aliens. The scientists also used the virtual reality environment to control and change flies’ flight direction, test to see if mice were afraid of virtual heights (they are), and even do something that hasn’t been done before in behavioral research: directly manipulate interaction between multiple individual animals.
Mice are not fans of virtual heights.
In partnership with the team of Dr. Iain Couzin from the University of Konstanz and the Max Planck Institute for Ornithology, the researchers developed a photorealistic model of a swimming, computer-controlled fish and placed it in the virtual environment with a real fish. The experiment showed that the real fish would most reliably follow the virtual fish when the latter matched its swim direction to the former.
The researchers named the system FreemoVR, and documented the research in a paper entitled “Virtual reality for freely moving animals,” which you can access here. Authors of the study include John R. Stowers, Maximilian Hofbauer, Renaud Bastien, Johannes Griessner, Peter Higgins, Sarfarazhussain Farooqui, Ruth M. Fischer, Karin Nowikovsky, Wulf Haubensak, Iain D. Couzin, Kristin Tessmar-Raible and Andrew D. Straw. You can learn more about FreemoVR here. Discuss in the Holodeck forum at 3DPB.com.
A fish in a swarm of space invaders.