In 2020, Keith Thomas dived into a pool, hit his head, and broke his neck. He was paralyzed from the chest down. Then, in a first-of-its-kind surgery last year, scientists implanted microchips into his brain to connect his thoughts to arm and hand movement, creating a two-way link—a “double bypass”—that allowed signals to travel in both directions. Now Thomas can open his hand, lift his arms, flex his biceps. “He used to have family members scratch his face if he had an itch,” says technology inventor Chad Bouton, professor at the Northwell Health Feinstein Institutes for Medical Research. “Now he can pet his dog.” The team hopes it could also help stroke survivors in the future.