Dec 12 2023

Virtual Reality for Mice

Scientists have developed virtual reality goggles for mice. Why would they do this? For research. The fact that it’s also adorable is just a side effect.

One type of neuroscience research is to expose mice in a laboratory setting to specific tasks or stimuli while recording their brain activity. You can have an implant, for example, measure brain activity while it runs a maze. However, having the mouse run around an environment puts limits on the kind of real time brain scanning you can do. So researchers have been using VR (virtual reality) for about 15 years to simulate an environment while keeping the mouse in a more controlled setting, allowing for better brain imaging.

However, this setup is also limiting. The VR is really just surrounding wrap-around screens. But it is technically challenging to have overhead screens, because that is where the scanning equipment is, and there are still visual clues that the mouse is in a lab, not the virtual environment. So this is an imperfect setup. k

The solution was to build tiny VR goggles for mice. The mouse does not wear the goggles like a human wears a VR headset. They can’t get them that small yet. Rather, the goggles are mounted, and the mouse is essentially placed inside the goggle while standing on a treadmill. The mouse can therefore run around while remaining stationary on the treadmill, and keep his head in the mounted VR goggles. This has several advantages over existing setups.

First, the VR experience is 3-D, because a different image can be presented to each eye. This makes the environment seem much more compelling and real. Further, the goggles take up the entire visual field of the mouse. There are no visual cues that the mouse is actually in a lab. Finally, the VR setup allows the researchers to present stimuli from anywhere, including overhead. This has actually allowed researchers to study the neurological response of the mouse to overhead visual threat for the first time. This is an important system in the mouse brain, as reacting to overhead predators (like a raptor) is extremely important to their survival.

This first study is an important proof-of-concept for this experimental setup, which seems to work really well. This will now make it much easier for researchers to ask a host of questions about how the mouse brain responds to specific situations. They can swap in any VR environment and stimuli. They next want to study how the mouse responds as predator, hunting for flies to eat.

VR neuroscience research also already exists in humans. In fact, it’s easier in humans because VR systems made for humans already exist. There are three basic types of research. The first is to explore the phenomenon of VR itself. It’s important to know if people respond to VR the same way they respond to reality, otherwise VR research would be introducing an artifact into research. I have discussed previously that the VR experience can be very real and visceral. My brain seems to completely buy into the reality that the VR experience is presenting, and reacts accordingly. In fact, a lot of initial neuroscience research using VR also used subjective reports to measure how “real” the VR experience is.

But that’s not good enough for science – we need some objective measure to see if a VR experience is real enough to justify neuroscience research, or if it is just a good simulation. At least one such study has been done, comparing real-world height exposure to VR to 2D stimulation. They found that the real world and VR experiences looked almost identical:

Behavioral and psychophysiological results suggest that identical exogenous and endogenous cognitive as well as emotional mechanisms are deployed to process the real-life and virtual experience. Specifically, alpha- and theta-band oscillations in line with heart rate variability, indexing vigilance, and anxiety were barely indistinguishable between those two conditions, while they differed significantly from the laboratory setup. Sensory processing, as reflected by beta-band oscillations, exhibits a different pattern for all conditions, indicating further room for improving VR on a haptic level.

There was only a small difference on sensory processing, which they attribute not to the visual stimuli but the tactile or “haptic” stimuli. This can be fixed by pairing VR goggles with some appropriate physical sensation (haptic feedback). We know from prior research (and subjective experience) that combining two or more sensory modalities creates a very compelling illusion of reality. VR combines sight and sound. But at even a little haptic sensation, like winds on the face, and the sensation is all the more real. I think the bottom line at this point is that VR is real enough to conduct neuroscience research, even if there is a little room for improvement.

The second is similar to this mouse study, looking at how the brain responds to a task or stimuli presented in VR. You can have a human, for example, navigate a maze in VR to see how the brain processes visuospatial information. VR is perfect for visuospatial processing, because that is the information the VR headset is presenting. This is the “low hanging fruit’ for VR neuroscience research. But really there are endless possibilities, especially if you add other sensory modalities.

Also, for mice it is easy to put them on a small treadmill. For a human the ultimate VR experience would be similar to what was portrayed in Ready Player One – the VR user is in a harness and standing on a multi-directional treadmill, wearing a full-body haptic feedback suit. This way your movements are translated into the VR experience, and anything that happens in VR can be sensed by the user. If you pick something up, you feel it in your hand, perhaps even a simulation of the weight. If you sit down on a virtual chair, you are sitting on the harness which holds you up. With my current headset only VR setup, I do have to remind myself that the virtual world is not really there. I cannot lean up against a virtual wall.

The third type of VR research is looking at VR as a tool of rehabilitation or psychological intervention. VR has been tested for phobias, PTSD, anxiety, and depression. Overall the research shows that VR therapy is effective. It may be a good adjunct to in person therapy. It is not necessary more effective than in person therapy, and I think researchers are still sorting out how best to use it, but so far it seems like a great additional option to have. There is even research looking at VR for physical rehabilitation, with promising results.

I think the bottom line is that VR is effective. Remember, our brains construct our internal sense of reality by processing multiple sensory streams. Swapping out sensory input for virtual input still leads to constructing a compelling reality, based on the virtual information. Our brain’s buy the illusion, because all perception is ultimately an illusion of sorts. We are already at the point where VR is more than adequate to work, and will only get more compelling as the technology improves. Beyond entertainment, this is already proving to be a boon to neuroscience research.

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