This diagram shows a VR setup with an “overhead threat” projected into the top field of view.Credit: Dom Pinke/Northwestern University
For the first time, the goggles allow researchers to study responses to overhead threats. northwestern university
Researchers have developed a new virtual reality (VR) goggle for mice. These tiny goggles aren’t just cute, they offer a more immersive experience for lab mice. By more faithfully simulating natural environments, researchers can more accurately and precisely study the neural circuits underlying behavior. A leap forward in VR goggles The new goggles represent a breakthrough compared to current state-of-the-art systems that simply surround a mouse with a computer or projection screen. Current systems allow the mouse to see the laboratory environment peeking out from behind the screen, but the flat nature of the screen prevents it from conveying three-dimensional (3D) depth. Another drawback was that the researchers couldn’t easily attach a screen above the mice’s heads to simulate overhead threats, such as looming birds of prey. New VR goggles avoid all of these problems. And as VR grows in popularity, the goggles could also help researchers gain new insights into how the human brain adapts and responds to repeated VR exposure. . This area is currently poorly understood. The study was published in the journal Dec. 8. neuron. This is the first time researchers have used a VR system to simulate overhead threats. A view through new miniature VR goggles.Credit: Dom Pinke/Northwestern University “For the past 15 years, we’ve been using VR systems on mice,” said Daniel Dombeck of Northwestern University, lead author of the study. “Traditionally, labs have used large computers and projection screens to surround the animals. For humans, this is like watching TV in the living room. You can still see the couch and walls. You There are cues around it that let you know you’re not in the scene. Next, consider wearing VR goggles, like the Oculus Rift, that occupy your entire field of vision, except the projected scene. They can’t see anything, and each eye projects a different scene to create depth information, which the rats lacked.” Dombeck is a professor of neurobiology in Northwestern University’s Weinberg College of Arts and Sciences. His laboratory is a leader in the development of his VR-based systems and high-resolution laser-based imaging systems for animal research. The value of VR Although researchers can observe animals in nature, it is extremely difficult to image patterns of brain activity in real time while animals interact with the real world. To overcome this challenge, the researchers integrated his VR into a laboratory setting. In these experimental settings, animals use a treadmill to move through a scene, such as a virtual maze, projected onto a screen around them. By keeping the mouse in place on a treadmill, rather than running it through a natural environment or a physical maze, neurobiologists can use tools to The brain can be observed and mapped. Ultimately, this will help researchers understand the general principles of how neural circuits activated during different behaviors encode information. “VR essentially recreates a real-life environment,” Dombeck says. “While we’ve had a lot of success with this VR system, the animals may not be as immersed as they would be in a real environment. Force the mouse to pay attention to the screen and ignore the surrounding lab.” That alone requires a lot of training.” Introduction to iMRSIV Recent advances in hardware miniaturization led Dombeck and his team to wonder if they could develop VR goggles that more closely replicate real-world environments. We created compact goggles using custom-designed lenses and a small organic light-emitting diode (OLED) display. The system, called Miniature Rodent Stereo Illumination VR (iMRSIV), consists of two lenses and two screens, one on each side of the head, that illuminate each eye individually for 3D vision. This provides each eye with a 180-degree field of view that fully immerses the mouse and excludes the surrounding environment. An artist’s interpretation of a cartoon of a mouse wearing VR goggles. Credit: @rita
Unlike VR goggles for humans, the iMRSIV (pronounced “immersive”) system does not wrap around the mouse’s head. Instead, the goggles are attached to experimental equipment and sit snugly right in front of the mouse’s face. Since the mouse runs in place on the treadmill, the goggles still cover the mouse’s field of view.
“We designed and built a custom holder for the goggles,” said John Issa, a postdoctoral fellow in Dombeck’s lab and co-first author of the study. “The entire optical display, the screen and lens, goes all the way around the mouse.” Enhance learning and engagement By mapping the brains of mice, Dombeck and his team found that the brains of mice wearing goggles activated in a manner very similar to that of freely moving animals. And in a side-by-side comparison, the researchers found that mice with goggles were able to immerse themselves in the scene much faster than mice with traditional VR systems. “We went through the same kind of training paradigm that we’ve done in the past, but the mice with the goggles learned faster,” Dombeck said. “After the first session they were already able to complete the task. They knew where to run and were looking for the right place to get the reward. We think they may not actually need as much training because they can interact with their environment in such a way.” Simulating overhead threats for the first time Next, the researchers used goggles to simulate overhead threats. This was not possible with the current system. Since the hardware for the imaging technology is already on top of the mouse, there is no place to attach a computer screen. But the skies above rats are often where animals are searching for important, sometimes life-or-death information. “The upper part of the visual field in mice is very sensitive to detecting predators from above, like in birds,” said co-first author Dom Pinke, a research specialist in Dombeck’s lab. . “It’s not a learned behavior. It’s an imprinted behavior. It’s hardwired into the mouse’s brain.” To create the looming threat, the researchers projected a dark, expanding disk onto the top of the goggles and above the mouse’s field of view. In experiments, mice ran faster and froze up when they noticed the disc. Both behaviors are common responses to overhead threats. Researchers were able to record neural activity to study these responses in detail. “In the future, we would like to investigate situations in which rats are predators rather than prey,” Issa said. “For example, we can observe brain activity while chasing a fly. This activity involves a lot of depth perception and distance estimation. Those are things we can start to capture. is.” Accessibility in neurobiological research Dombeck hopes the goggles will not only open the door to further research, but also to new researchers. He believes the goggles could make neurobiology research more accessible because they are relatively inexpensive and require less intensive laboratory preparation. “Traditional VR systems are very complex,” Dombeck says. “It’s expensive and it’s big. You need a large lab with plenty of space. Additionally, the long time it takes to train a mouse to perform a task limits the number of experiments you can perform. Although we are still working on improvements, our goggles are small, relatively inexpensive, and also very easy to use. This could make VR technology available to other labs. There is a gender.” References: “Full-field virtual reality goggles for mice” by Domonkos Pinke, John B. Issa, Gabriel A. Dara, Gergely Dobos, Daniel A. Dombeck, December 8, 2023. neuron.DOI: 10.1016/j.neuron.2023.11.019 This research “Full-field virtual reality goggles for mice” National Institutes of Health (Award Number R01-MH101297), the National Science Foundation (Award Number ECCS-1835389), the Hartwell Foundation, and the Brain and Behavioral Research Foundation. (function(d, s, id){
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