Why scientists made mini virtual reality goggles for mice

By Isobel Williams via SWNS

New miniature Virtual Reality goggles for MICE could revolutionize lab testing, say scientists.

Besides just being cute, these miniature goggles provide more effective and cheaper immersive experiences for mice living in laboratory settings.

Compared to current state-of-the-art systems, which simply surround mice with computer or projection screens, the new goggles provide a leap in advancement.

By more faithfully simulating natural environments, the researchers can more accurately and precisely study the brain function behind their behavior.

In current systems, mice can still see the lab environment peeking out from behind the screens, and the screens’ flat nature cannot convey three-dimensional (3D) depth.

Researchers have also been unable to easily mount screens above mice’s heads to simulate overhead threats, such as looming birds of prey.

These new VR goggles, from Northwestern University, Illinois, bypass all those issues.

Dr. Daniel Dombeck said: “For the past 15 years, we have been using VR systems for mice.

“So far, labs have been using big computer or projection screens to surround an animal. For humans, this is like watching a TV in your living room.

"You still see your couch and your walls. There are cues around you, telling you that you aren’t inside the scene.

“Now think about putting on VR goggles, like Oculus Rift, that take up your full vision. You don’t see anything but the projected scene and a different scene is projected into each eye to create depth information. That’s been missing for mice.”

Although scientists could study mice in nature, it is not easy to get real-time brain activity readings in that environment.

In a VR lab experiment, an animal uses a treadmill to navigate scenes, such as a virtual maze, projected onto surrounding screens.

Dr. Dombeck added: “VR basically reproduces real environments.

“We’ve had a lot of success with this VR system, but it’s possible the animals aren’t as immersed as they would be in a real environment.

“It takes a lot of training just to get the mice to pay attention to the screens and ignore the lab around them.”

These flaws inspired the team to create their miniature VR goggles, to help replicate a more realistic experience.

They called their invention Miniature Rodent Stereo Illumination VR (iMRSIV).

The device provides each eye with a 180-degree field of view that fully immerses the mouse and excludes the surrounding environment.

Unlike VR goggles for a human, the iMRSIV (pronounced “immersive”) system does not wrap around the mouse’s head. Instead, they are closely perched in front of the mouse's face.

Dr. John Issa said: “We designed and built a custom holder for the goggles. The whole optical display — the screens and the lenses — go all the way around the mouse.”

Tests of their new system found that not only was it much more accurate than traditional VR systems, but the results were very similar to those in freely moving animals.

Dr. Dombeck said: “We went through the same kind of training paradigms that we have done in the past, but mice with the goggles learned more quickly.

“After the first session, they could already complete the task. They knew where to run and looked to the right places for rewards.

“We think they actually might not need as much training because they can engage with the environment in a more natural way.”

With these new goggles, scientists can now see how mice react to an overhead threat.

They projected a dark disk at the top of the mice’s fields of view to suggest this looming threat.

Results, published in the journal Neuron, showed that upon noticing the disk the mice either ran faster or froze.

Dr. Issa said: “In the future, we’d like to look at situations where the mouse isn’t prey but is the predator.

“We could watch brain activity while it chases a fly, for example. That activity involves a lot of depth perception and estimating distances. Those are things that we can start to capture.”

The team hopes that their goggles will be able to be used to study how the human brain adapts and reacts to repeated VR exposure.

Dr. Dombeck concluded: “Traditional VR systems are pretty complicated. They’re expensive, and they’re big. They require a big lab with a lot of space. And, on top of that, if it takes a long time to train a mouse to do a task, that limits how many experiments you can do.

“We’re still working on improvements, but our goggles are small, relatively cheap and pretty user-friendly as well. This could make VR technology more available to other labs.”