Chinese scientists have developed the world’s lightest wireless mesoscope, a miniature microscope weighing just 1 gram that can record 25 times as many neurons in mice as comparable devices.
The device, named Airscope, was unveiled in the prestigious journal Nature on Oct. 19, and developed by a team led by Tsinghua University professor Dai Qionghai and Chinese PLA Medical School professor Dai Pu, in collaboration with researchers from other institutions.
When installed on a mouse’s head, the Airscope can record activity from over 8,500 neurons as it freely explores, climbs, and interacts with other mice.
Previously, microscopes designed to image large areas of the brain at high resolution often required cables or the subject to be restrained, making it difficult to study natural behavior. Meanwhile, head-mounted microscopes that let animals move freely could observe only limited areas.
In contrast, the Airscope combines wireless operation with mesoscopic imaging, allowing scientists to observe large areas of tissue while still distinguishing individual cells. This enables researchers to “understand how large numbers of neurons interact and work together to produce complex functions,” Wu Jiamin, an associate professor in Tsinghua University’s Department of Automation and one of the study’s corresponding authors, said in an article published Tuesday by Tsinghua University.
The device weighs just 1 gram without its battery, more than 30% less than the latest head-mounted mesoscopes, according to the researchers. It has single-cell resolution of 4 to 6 micrometers, and a 6-millimeter field of view compared with typically less than 1 millimeter for conventional head-mounted devices. A magnetically attached battery can be replaced in two seconds.
With the Airscope, the team conducted several experiments that were previously difficult because of cables or equipment weight.
For example, in a simulated natural habitat with ramps, tree hollows, and shelters, mice could explore freely while researchers recorded their cortical activity. The team could also use neural signals to predict which portion of the habitat a mouse was in.
In another experiment, researchers placed two mice at opposite ends of a narrow tube and used their neural activity to predict which would force the other to retreat, achieving over 80% accuracy.
Other experiments included mounting one Airscope on a mouse’s head and another on its back to compare spinal cord and cortical neural activity, as well as tracking mice exploring a large maze in search of water rewards.
The team has also publicly released several datasets collected from their experiments.
Zhang Yuanlong, one of the study’s first authors and an assistant professor at Tsinghua University’s Center for Life Sciences and Artificial Intelligence and Department of Automation, said the team used AI to help optimize the optical design. The technology also uses a 2-megapixel image sensor, whereas previously published wireless systems had not exceeded 1 megapixel, allowing higher resolution.
Dai Qionghai said the Airscope could enable “more precise neural detection” and potentially expand into fields such as immunology and cancer research.
Zhang added that the device could be used to track the progression of Alzheimer’s disease, brain injuries, cardiovascular diseases, depression, and other conditions in animal models, and gain insights into disease mechanisms, prevention, and treatment.
In 2023, researchers at the Massachusetts Institute of Technology developed two head-mounted microscopes using a new optical design: one optimized for a larger field of view, measuring around 4 millimeters and weighing 1.4 grams, and another optimized for lower weight, with a 1-millimeter field of view and weighing just 1 gram. Both devices required wires for power and data collection.
Editor: Marianne Gunnarsson.
(Header image: Visuals from the WeChat public account of Tsinghua University, reedited by Sixth Tone)