Although it may seem unbelievable, scientists have been using virtual reality devices to study the brain activity of laboratory mice for years. In the past this was done by having the mice surrounded by flat screens, now by the Northwestern University team in an effort to create an even more immersive experience, he developed virtual reality glasses that fit on a mouse’s head, but the holder also wraps around its entire body. This enabled them for the first time simulate overhead threats and map mouse brain activity all the while.

A system called Miniature Rodent Stereo Illumination VR (iMRSIV) is not attached to the head of the mouse like a VR headset for humans. Instead, the goggles sit in front of the treadmill and surround entire field of view of the mousewhich running in place. “We designed and manufactured our own eyeglass holder,” said John Issa, co-author of the study. “The entire optical display—screens and lenses—is located around the entire mouse.”

The researchers say that the tests showed that the mice got used to the new VR environment faster than with the previous devices. The team simulated the presence of threats above the mouse’s head, such as birds, by projection spreading dark spots at the top of the display. The way mice react to this type of threat is not learned behavior, it is innate behavior.

Thanks to this method, scientists were able to record how external physical responses of micesuch as freezing in place or accelerating, so their neural activity. In the future, they may reverse this scenario and have mice play the role of predators to find out what happens when they hunt insects.