American scientist Karl Deisseroth and German researchers Peter Hegemann and Georg Nagel have won the 2026 Nobel Prize in Physiology or Medicine for discoveries that transformed scientists’ ability to study the brain using light.
The Nobel Assembly of Sweden’s Karolinska Institutet said the three scientists were awarded the prize for their “discoveries concerning light-gated ion channels and optogenetics”. The prize carries a total award of 12 million Swedish crowns ($1.2 million), to be shared among the three laureates.
Optogenetics makes it possible to control the activity of individual nerve cells in a living brain, according to Thomas Perlmann, secretary-general of the Nobel Assembly. “This method is now being used in laboratories around the world to reveal the brain’s mysteries,” he said.
The technique has also moved towards clinical applications. Researchers involved in clinical trials are attempting to restore vision in people blinded by retinitis pigmentosa by inserting a light-sensitive protein into the retina. Scientists are also exploring whether optogenetics could improve cochlear implants by allowing more precise stimulation of the auditory nerve than existing electrical devices.
The work began with Hegemann’s research in the early 1990s into how the alga Chlamydomonas responds to light within half a millisecond. He proposed that a single protein could capture light and function as an ion channel. Nagel subsequently tested the hypothesis by injecting Chlamydomonas genes into frog eggs and discovered channelrhodopsin-2, an ion channel that opens when exposed to light.
Hegemann and Nagel reported in 2003 that the protein could be introduced into human and hamster cells, where light could then be used to generate electrical impulses. In 2005, Deisseroth, a scientist at Stanford, demonstrated the technique in rat nerve cells. The method was named optogenetics the following year.
Perlmann said he had spoken to all three laureates on Monday morning and described them as surprised and delighted by the award. He said all three expressed particular pleasure at receiving the prize together and referred to one another as friends.
The medicine prize traditionally begins the annual Nobel announcements, followed by awards for physics, chemistry, literature, peace and economics over the following days. The five original Nobel Prizes were established under the will of Swedish inventor and industrialist Alfred Nobel and have been awarded since 1901, with limited interruptions, mainly during the First and Second World Wars. Sweden’s central bank established the economics prize in 1968.
The medicine prize has previously recognised discoveries including Alexander Fleming’s work on penicillin in 1945 and Karl Landsteiner’s discovery of human blood groups in 1930. Last year, Americans Mary Brunkow and Fred Ramsdell and Japan’s Shimon Sakaguchi received the medicine prize for work explaining how the immune system avoids attacking healthy cells, opening possibilities for new treatments for diseases including cancer.
The Nobel celebrations culminate on December 10, the anniversary of Nobel’s death, when the laureates receive their awards at ceremonies attended by the royal families of Sweden and Norway before gala banquets are held in their honour.
