NATURE BRIEFING 23 April 2026 ‘Ace’, a robotic arm, can best elite ping-pong players. Plus, a new network of cells in a mouse’s brain and monkeys in Gibraltar are eating dirt to settle their stomachs. You have full access to this article via your institution. Hello Nature readers, would you like to get this Briefing in your inbox free every day? Sign up here . The lesser-known brain cells called astrocytes form their own networks in the brain. Credit: Prof. Stephen Waxman, Hank Morgan/Science Photo Library The brain’s ‘secret subway system’ Brain cells called astrocytes form extensive networks in the mouse brain that are similar in some ways to those formed by neurons. Researchers have compiled a whole-brain 3D map of astrocyte networks — the first of its kind , they say. The atlas reveals how webs of these cells connect far-flung regions of the brain, allowing them to exchange molecules with each other over long distances.…