Nobel in medicine given to American, Germans for brain study

The Nobel Assembly on Monday awarded its 2026 Prize in Physiology or Medicine to a trio of scientists who discovered optogenetics, a method of controlling nerve signals with light. The laureates are American Karl Deisseroth, of the Howard Hughes Medical Institute and Stanford University, and Germans Peter Hegemann and Georg Nagel. They laid the foundation of a new era in neuroscience and made it possible to see how nerve cells shape memories, feelings, and behaviors in a living brain, the assembly said.

How did the discovery happen? Hegemann and Nagel laid the foundation for the breakthrough in the early 2000s when they discovered a protein, channel-rhodopsin, in a single-celled piece of algae, according to the Nobel assembly. Hegemann wondered how the alga, Chlamydomonas, was able to swim toward a light source. He and Nagel discovered that when blue light hit the protein, which is located on the surface of the organism, it opened a channel for charged ions to flow into the cell and create an electrical impulse. When they put that same protein into other cells, those cells also became responsive to light, according to the Nobel assembly.

Deisseroth conducted experiments with rats and mice over the next few years, in which he introduced the channel-rhodopsin protein into their nerve cells. He used blue light to trigger nerve signals, essentially using the protein as a light-controlled switch. His method has allowed researchers around the world to find neural circuits governing specific memories, feelings, and behaviors and learn about neurological and psychiatric disorders, according to the Nobel assembly. Some researchers are also using the method to try to bring back the sight of people with visual impairments, the assembly said.

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