STOCKHOLM — American Karl Deisseroth and Germans Peter Hegemann and Georg Nagel won the 2026 Nobel Prize in Physiology or Medicine on Monday for their discoveries on light and optogenetics that have helped understand how the brain works. The Nobel Assembly of Sweden's Karolinska Institute medical university said Deisseroth, 54, Hegemann, 71, and Nagel, 73, were selected for their "discoveries concerning light-gated ion channels and optogenetics." Optogenetics "makes it possible to switch on, or off, the activity of individual nerve cells in a living brain," said Thomas Perlmann, Secretary-General of the Nobel Assembly at Karolinska Institutet. "This method is now being used in laboratories around the world to reveal the brain’s mysteries," Perlmann said. In clinical trials, researchers are restoring vision to people blinded by a condition called retinitis pigmentosa by inserting a light-sensitive protein in the retina. Researchers also hope optogenetics could improve cochlea implants, allowing more precise stimulation of the auditory nerve than current electrical devices. The physiolog