Three scientists win medicine Nobel for illuminating brain activity

Three scientists who helped develop a way to switch nerve cells on and off with light have won the 2026 Nobel Prize in Physiology or Medicine, the Nobel Assembly announced Monday. Their work in optogenetics has given researchers a powerful tool for studying how the brain produces memories, feelings and behavior.

The winners are Karl Deisseroth, 54, of Stanford University in the United States; Peter Hegemann, 71, of Humboldt University of Berlin; and Georg Nagel, 73, of the University of Würzburg in Germany. The Nobel Assembly at Sweden’s Karolinska Institute honored them “for their discovery of a molecular switch for nerve cells.” They will share 12 million Swedish kronor, about $1.2 million.

Optogenetics allows scientists to use light to control electrical activity in selected nerve cells. Researchers can switch individual cells or neural circuits on and off in a living brain, then observe how those changes affect its activity. The method is used to investigate the roles of different cells in learning, fear, addiction and movement.

“Optogenetics has fundamentally altered our understanding of the brain,” the Nobel Assembly said. “Every day brings new discoveries, helping to solve one of humanity’s great mysteries: how our incredible brain works.”

The BBC reported that Hegemann and Nagel discovered channelrhodopsin, a light-sensitive protein found in algae, in the early 2000s. Deisseroth then worked out how to use the protein to switch on nerve cells in the brains of mice. Since then, researchers have used the approach to study nerve cells and pathways in animals.

The Nobel Committee said scientists can now use light to bring memories to life, create feelings and drive behaviors while studying neurons involved in psychiatric and neurological disorders. The work is also providing insight into how the nervous system interacts with cells elsewhere in the body, including the heart and gut, the committee said, according to the BBC.

“Optogenetics provides opportunities for mapping the brain in a way that we could once only dream of,” said Per Svenningsson, chair of the Nobel committee. Thomas Perlmann, secretary-general of the Nobel Assembly, said the method “is now being used in laboratories around the world to reveal the brain’s mysteries.”

Researchers are exploring possible medical uses. The BBC reported that clinical trials are testing an approach to restore sight in people blinded by retinitis pigmentosa, a disease that destroys light-sensing cells in the eye. In one case described by the Nobel Committee, a patient regained some vision after receiving a light-sensitive protein in the affected part of the eye and wearing glasses that emit light. Al Jazeera reported that researchers also hope optogenetics could lead to cochlear implants that stimulate the auditory nerve more precisely than current electrical devices.

Perlmann said he reached all three winners by phone. Each called it “absolutely wonderful” to share the prize with the other two, whom they regard as friends, he said.

The medicine award opens the annual Nobel announcements. Prizes in physics, chemistry, literature and peace are scheduled for later this week, followed by the economics prize on Oct. 12.