Virtual reality arena for fish. Source: Straw LabVirtual reality arena for fish. Source: Straw LabExperimental designs to better understand brain function are being created with virtual reality.

Most current research that studies the complex interactions of neurons underlying behavior require full or partial immobilization of an animal, which restricts sensory input and feedback – and ultimately impacts neuronal and behavioral responses. But a new system called FreemoVR takes a different approach.

As presented in the journal Nature Methods, FreemoVR immerses a freely-moving animal in a reactive, computer-controlled three-dimensional world. Lead developer Andrew Straw of the University of Freiburg refers to the system as a “holodeck.”

Computer displays create the walls and floors of behavioral arenas – allowing an experimenter to control an animal's visual experience while maintaining natural feedback for its tactile senses. Using zebrafish, flies and mice, researchers used the system to investigate naturalistic responses as animals swam, flew or walked through the VR environment.

"We wanted to create a holodeck for animals […] a reactive, immersive environment under computer control so that we could perform experiments that would reveal how they see objects, the environment, and other animals," said Straw.

The system was sensitive enough to reveal previously unnoticed behavioral differences between wild type and mutant zebrafish strains. It also helped scientists further explore the rules that govern social interactions of real zebrafish with virtual ones – for instance, a prospective leader fish would minimize the risk of losing followers by balancing swimming direction preference with the social responsiveness of the subordinate fish.

"I am particularly excited about the possibility to mimic more complex, naturalistic environments and to test more advanced brain functions in medaka and zebrafish,” said Max F. Perutz Laboratories (MFPL) scientist Kristin Tessmar-Raible, who led most of the fish work. “It will help us to better understand brain functions, and to what extent we can use these diurnal vertebrates as models for neuropsychological malfunctions.”

The researchers hope to use FreemoVR to gain insights into the brain function behind high-level behaviors like navigation, to better understand causality in the collective behavior of social groups and eventually to study behavior mechanisms connected to the conditions in which the brain evolved to operate.

Adapted from a University of Vienna press release.