Mice are now diving into virtual worlds thanks to a custom-made headset. An innovation that could shed light on certain aspects of the brain and open new avenues for medical research.
Researchers at Cornell University have designed a virtual reality headset tailored for mice, called MouseGoggles. Made up of smartwatch screens and miniature lenses, this device offers total visual immersion, with a field of view of 230 degrees horizontally and 140 degrees vertically. The mice, placed on a treadmill, explore virtual environments while being observed by scientists.
The main goal of this technology is to study brain mechanisms related to spatial navigation and memory. Researchers hope to better understand diseases like Alzheimer's by observing how mice react to complex visual stimuli.
In this study, the mice were equipped with a fixed headset while being placed on a rotating sphere that serves as a treadmill. This setup allows the rodents to move freely in a virtual environment while keeping their heads stable for precise observation. The headset, composed of miniature screens and lenses, projects high-frequency stereoscopic images, creating a realistic visual immersion.
The researchers also use integrated cameras to track eye movements and changes in pupil size, providing precise data on the engagement and reactions of the mice. This combination of virtual reality and eye tracking allows for the study of brain functions under controlled conditions.
During tests, the mice showed surprising reactions. For example, when faced with a dark spot simulating an approaching predator, they startled, a sign that they perceived the threat as real. This reaction, absent with less immersive systems, confirms the effectiveness of the device. The researchers published their results in
Nature Methods, highlighting the importance of this advancement for neuroscience.
a) Frontal (top) and lateral (bottom) views of a mouse fixed on a linear treadmill, equipped with a MouseGoggles Duo headset (version 1.1) at three tilt angles: 15° (left), 30° (middle), and 45° (right).
b) Estimated coverage of the headset's visual field for the three mentioned tilt angles.
c) Whisker map showing constant/full, temporary/partial, or no contact with the headset at the three angles, measured on three different mice.
The MouseGoggles could also improve the study of blood flow in the brain. Previous research has shown that improving blood circulation in mice with Alzheimer's boosted their memory within hours. This headset will allow for deeper exploration of these findings by providing a more precise and immersive experimental framework.
In the future, researchers plan to develop mobile versions for larger rodents, such as rats. They would also like to integrate other senses, such as smell or taste, to create multisensory experiences. These innovations could open new perspectives in the study of complex behaviors and neurodegenerative diseases.
What is pupillometry and why is it important in neuroscience?
Pupillometry is a technique that measures changes in pupil size in response to visual or cognitive stimuli. These changes, often imperceptible to the naked eye, are controlled by the autonomic nervous system and reflect brain activity. In neuroscience, this method is used to study attention, emotion, and cognitive processes.
Pupils dilate or contract depending on light intensity, but also in response to emotional or mental stimuli. For example, a stressful situation can cause pupil dilation. These reactions provide valuable clues about the mental state of an individual or animal.
In the case of MouseGoggles, pupillometry allows researchers to measure the engagement of mice in virtual environments. By tracking changes in pupil size, researchers can assess whether the mice perceive the stimuli as real and how their brains process this information.
This technique is particularly useful for studying neurodegenerative diseases like Alzheimer's. By analyzing pupillary reactions, scientists can better understand cognitive dysfunctions and test the effectiveness of new treatments. Pupillometry thus offers a unique window into brain function.
Article author: Cédric DEPOND