The Nobel Assembly at Karolinska Institutet in Sweden has awarded the 2026 Nobel Prize in Physiology or Medicine jointly to U.S. psychiatrist and neuroscientist Karl Deisseroth and German scientists Peter Hegemann and Georg Nagel “for their discoveries concerning light-gated ion channels and optogenetics.”
The prize honors optogenetics, a method that makes it possible to show how nerve cells shape memories, feelings and behaviors in the living brain. Hegemann and Nagel discovered a remarkable protein, channelrhodopsin, in a single-celled alga, and Deisseroth transformed the protein into a light-controlled switch for nerve cells. According to the Nobel Assembly, the laureates have laid the foundation of a new era in neuroscience.
From an alga’s curiosity to a map of the brain
It began with Hegemann’s curiosity about how Chlamydomonas, a single-celled alga, is able to swim toward a light source. In the early 2000s, he and Nagel discovered channelrhodopsin on the surface of the cell. When illuminated by blue light, a channel opens through the protein and charged ions flow into the cell, creating an electrical impulse. Whatever cell they put the protein in, that cell became light sensitive.
Deisseroth introduced the gene for channelrhodopsin into nerve cells from rats and, by illuminating them with blue light, was able to trigger a nerve signal. He published the breakthrough in 2005, and two years later made the light-controlled switch work in the brains of living mice.
Using optogenetics, researchers have revealed neural circuits governing specific memories, feelings and behaviors relevant to neurological and psychiatric disorders, and in clinical medicine the method is being used in attempts to restore sight in people with visual impairment. “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 for Physiology or Medicine.
The laureates
Karl Deisseroth, born in 1971, is a professor of bioengineering and of psychiatry and behavioral sciences at the Howard Hughes Medical Institute and Stanford University. Peter Hegemann, born in 1954, is a senior professor of neuroscience at Humboldt University of Berlin; his prize-winning discoveries were made at the Max Planck Institute for Biochemistry in Martinsried. Georg Nagel, born in 1953, is a professor of molecular plant physiology at the University of Würzburg; his discoveries were made at the Max Planck Institute for Biophysics in Frankfurt.
The prize amount of 12 million Swedish kronor will be shared equally among the three laureates. This year’s Nobel Prizes are being announced from Oct. 5 to 12.
