Tiny virtual reality goggles for mice create convincing worlds that allow scientists to study the animals鈥� brain activity in a range of scenarios. The technology takes rodent neuroscience closer to The Matrix, towards a simulation that is indistinguishable from the real world, according to the researchers
For around 20 years, at Northwestern University in Illinois and his colleagues have used rudimentary virtual reality to learn more about the way that mice鈥檚 brains work.
Machines that observe brain patterns are too large to be attached to freely moving mice. Instead, the team placed screens showing a virtual reality world around a mouse as it was held inside such a machine and then put it on a treadmill. The researchers could then create a virtual world where the mouse navigated any environment they designed.
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鈥淲e can have them run through virtual mazes, imaging their brains to see which neurons are forming memories and remembering where they are,鈥� says Dombeck. 鈥淸But] it鈥檚 a flat thing that the animal is looking at and there鈥檚 no depth perception, and the mice can see stuff that isn鈥檛 part of the projection. So there鈥檚 all these cue conflicts that are around and they鈥檙e not, we think, fully engaged and immersed in the environment. They鈥檙e not fully tricked.鈥�
To solve that problem, the researchers have now created tiny goggles that cut out everything from a mouse鈥檚 field of view except the virtual world, with a different screen for each eye to create convincing depth perception. They believe this will allow them to run more accurate experiments, as mice will be more convinced of the illusion and therefore behave more naturally.
But designing goggles for mice isn鈥檛 as simple as just miniaturising technology made for people. While humans have a field of view of just over 200 degrees, it is up to 320 degrees in mice.
This means the screens within their goggles need to be curved and almost surround their eyeballs. The screens can only display 400 pixels square, but Dombeck says that is enough to be convincing, as the vision of mice is far less detailed than that of people.
鈥淥ur first use of the goggles in the first set of mice was pretty remarkable,鈥� says Dombeck. 鈥淭he mice seemed to engage very quickly. We put the goggles on 鈥� it鈥檚 all black, they don鈥檛 see anything 鈥� and then we turn on the virtual rendering. The first mouse kind of sat up and was like 鈥榃hoa, what is this?鈥� and then started moving around pretty naturally, which typically doesn鈥檛 happen with those flat projection screens.鈥�
Dombeck says the long-term goal is to make technology for mice equivalent to that seen in The Matrix, with additional equipment to trick their senses of smell, hearing and touch.
Neuron
