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September 29, 2025—The complete nervous system of a mouse, mapped. Plus, fashion's waste problem and storms in the Atlantic. —Andrea Gawrylewski, Chief Newsletter Editor | | Scientists have mapped the entire nervous system, or "connectome," of a mammalian body for the first time. Scientists removed material from 16 mice's bodies that would block light, such as fat and calcium, to make them as transparent as possible. Then, using a custom combined slicing tool and microscope, the scientists took images of the mice bodies. Seven of the mice were genetically modified to have fluorescent neurons. Four were immunostained to have proteins in the sympathetic nervous system with different colors. And in the last five, researchers used viruses to measure the full length of the axons of the nerve projections. Each vagus nerve fiber connected to only one organ in the gut, rather than branching to many different organs as some had predicted. Why this matters: Rather than just homing in on the brain and spinal cord, which have historically been given more attention, researchers included the nerve fibers from the peripheral nervous system (PNS), too. This network of nerves lets mammals walk, controls eye movements, and sends alerts of pain. Mapping them out helps scientists understand how the nerves interact with organs and how the physiology of our nerves underlies disease, potentially inspiring treatments. What the experts say: "By revealing the precise projection patterns and organ-specific targeting of different peripheral nerves, these maps will provide a structural framework for understanding how the PNS mediates body physiology," says co-author of the study Guo-Qiang Bi, a biophysicist at the University of Science and Technology of China. —Andrea Tamayo, Newsletter Writer | | At left, nerves (blue) are visible in a reconstructed view of their paths through a mouse. At right, the sympathetic nerves appear in purple. "High-Speed Mapping of Whole-Mouse Peripheral Nerves at Subcellular Resolution," by Mei-Yu Shi et al., in Cell, Vol. 188, No. 14; July 10, 2025 (CC BY 4.0) | | In September the fashion world turns its attention to the biggest runway shows: in New York City, London, Milan and Paris (starting today) designers exhibit their spring lines. These are a feast for the eyes, but (as any fan of the movie The Devil Wears Prada knows) the looks on the runway also go on to inspire myriad clothing designs worn by everyday people, many of which are produced en masse and sold at low prices. So-called fast fashion has an enormous ecological footprint. Why it matters: Projections indicate that by 2030 the world will be producing 134 million tons of textile waste every year. In the U.S. alone, at least 17 million tons of textiles are discarded annually, which works out to about 100 pounds of clothes per person. | | | | |
BROUGHT TO YOU BY SCIENTIFIC AMERICAN TRAVEL | | Take the Eclipse Trip of a Lifetime Experience the 2026 total solar eclipse in Iceland, Land of Fire and Ice. Led by Senior News Editor Andrea Thomspon, your tour of Iceland's dramatic landscapes culminates in a private eclipse viewing party at an otherworldly lava-field base camp. Learn More. | | | | |
Hans-Karl Eder/Spektrum der Wissenschaft, restyled by Amanda Monta├▒ez | | Today I'm reminded why I love science so much. It can illuminate the fluid dynamics of storm movement over the ocean. It gives researchers the tools to build a transparent mouse in order to literally see the mammalian nervous system at work. It can help devise new technologies that repurpose clothing fabrics and save them from the world's teeming landfills. Science is everywhere and might help us overcome any challenge we have. Every story is a science story. | | From one science lover to another, thank you for reading Today in Science. Send any feedback to: newsletters@sciam.com. See you tomorrow! —Andrea Gawrylewski, Chief Newsletter Editor
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