American psychiatrist and neurologist Karl Deisseroth and German scientists Peter Hegemann and Georg Nagel have won the 2026 Nobel Prize in Physiology or Medicine for discoveries that laid the foundation for optogenetics, a technique that allows scientists to control individual nerve cells using light.
The Nobel committee said their work has opened a new era in neuroscience, helping researchers understand the neural circuits behind specific memories, feelings and behaviours linked to neurological and psychiatric disorders.
The Nobel Assembly of Sweden’s Karolinska Institute announced on Monday that Deisseroth, 54, Hegemann, 71, and Nagel, 73, were selected for their “discoveries concerning light-gated ion channels and optogenetics.”
Thomas Perlmann, Secretary-General of the Nobel Assembly at Karolinska Institutet, said optogenetics makes it possible to switch the activity of individual nerve cells in a living brain on or off.
The technique is now being used in laboratories around the world to investigate the brain and unravel some of its most complex mysteries.
The trio’s discoveries have helped scientists gain a deeper understanding of how the human brain works and have provided new ways to study the biological mechanisms behind behaviour, memory and emotions.
Research could help restore sight
The impact of optogenetics is moving beyond laboratory research, with scientists exploring its potential in clinical medicine.
Researchers are currently using the method in clinical trials aimed at restoring vision in people who have been blinded by retinitis pigmentosa. The approach involves inserting a light-sensitive protein into the retina so that cells can respond to light.
Scientists are also investigating whether optogenetics could improve cochlear implants by allowing more precise stimulation of the auditory nerve than existing electrical devices.
How Nobel-winning discovery began
Hegemann’s research dates back to the early 1990s, when he studied how the single-celled alga Chlamydomonas responds to light in just half a millisecond.
He proposed that a single protein could capture light and function as an ion channel. Nagel subsequently tested the idea by injecting Chlamydomonas genes into frog eggs, leading to the discovery of channelrhodopsin-2, an ion channel that opens when exposed to light.
In 2003, Hegemann and Nagel published research showing that the protein could be introduced into human and hamster cells, allowing light to generate electrical impulses.
Two years later, Deisseroth, a Stanford researcher, demonstrated that the technique could be used in rat nerve cells. The method was subsequently given the name “optogenetics” in 2006.
Their work ultimately provided scientists with a powerful tool for manipulating and studying the activity of specific neurons.
Laureates surprised, delighted by Nobel honour
Perlmann said he had spoken to all three laureates on Monday morning and described them as surprised and delighted by the announcement.
According to Perlmann, all three expressed particular happiness at receiving the award alongside the other two scientists, whom they described as friends.
The laureates will share a prize sum of 12 million Swedish crowns, equivalent to about $1.2 million.
Medicine prize opens Nobel announcements
The Physiology or Medicine award traditionally opens the annual Nobel Prize announcements, with prizes in physics, chemistry, literature, peace and economics to follow over the coming days.
The original five Nobel Prizes were established under the will of Swedish inventor and industrialist Alfred Nobel and have been awarded since 1901, apart from limited interruptions, mainly during the First and Second World Wars.
The economics prize was added later in 1968 by Sweden’s central bank, the Riksbank.
The medicine prize has recognised some of the most influential scientific discoveries of the past century. Among its notable recipients are Alexander Fleming, honoured in 1945 for his work on penicillin, and Karl Landsteiner, who received the prize in 1930 for discovering human blood groups.
Last year’s medicine prize went to American scientists Mary Brunkow and Fred Ramsdell and Japan’s Shimon Sakaguchi for research explaining how the immune system prevents attacks on healthy cells, work that could open avenues for new treatments for diseases including cancer.
Nobel traditions continue more than century later
Nobel laureates are selected by expert committees appointed by the institutions responsible for awarding the prizes. The awards are presented in Stockholm, except for the Nobel Peace Prize, which is awarded in Oslo. The separate location is a tradition often associated with the political union that linked Sweden and Norway during Alfred Nobel’s lifetime.
More than 125 years after Nobel signed his will, the prizes continue to retain many of their longstanding traditions.
The celebrations culminate on December 10, the anniversary of Nobel’s death, when the laureates formally receive their awards at ceremonies attended by the royal families of Sweden and Norway.
The winners are also honoured at gala banquets held in their honour, marking the culmination of one of the world’s most prestigious celebrations of scientific and intellectual achievement.
