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| The 2026 Nobel Prize in Physiology or Medicine is announced in Stockholm for Karl Deisseroth, Peter Hegemann and Georg Nagel. |
The Nobel Assembly at Sweden's Karolinska Institute announced Monday that three scientists will share this year's prize in physiology or medicine for discoveries that established optogenetics, a research method that allows scientists to switch specific brain cells on or off using pulses of light.
The laureates are Karl Deisseroth, 54, an American psychiatrist and neuroscientist at Stanford University; Peter Hegemann, 71, a professor of experimental biophysics at Humboldt University in Berlin; and Georg Nagel, 73, a professor of plant physiology at the University of Wurzburg in Germany. They will split the 12 million Swedish krona prize, worth about $1.2 million.
The Nobel Assembly said the three were recognized for "discoveries concerning light-gated ion channels and optogenetics."
How the discovery began
The work grew out of Hegemann's curiosity about a single-celled alga called Chlamydomonas, which can swim toward a light source. In the early 1990s, he investigated how the organism reacts to light in half a millisecond and hypothesized that a single protein both captured light and acted as an ion channel.
Nagel tested that idea by injecting Chlamydomonas genes into frog eggs, which led to the discovery of channelrhodopsin-2, a light-sensitive ion channel. In 2003, the two researchers published findings showing the protein could be introduced into human and hamster cells to generate electrical impulses using light.
Deisseroth built on that work at Stanford. He introduced the gene that codes for the protein into the nerve cells of rats and, by illuminating those cells, was able to control the movement of mouse whiskers around 2007. The method was named optogenetics in 2006. He also used light to wake sleeping mice, confirming that specific nerve cells control wakefulness.
A new way to map the brain
Thomas Perlmann, secretary-general of the Nobel Assembly, described the technique as one that "makes it possible to switch on, or off, the activity of individual nerve cells in a living brain."
"This method is now being used in laboratories around the world to reveal the brain's mysteries," Perlmann said.
Anna Wedell, a professor of molecular medicine at Karolinska, said the discovery changed how scientists can study the brain. "Before, we had an anatomical map of the brain," she said. "Now we can generate functional maps, and we can also understand how different cells speak to each other across the brain."
According to the Nobel committee, researchers have since used optogenetics to identify neural circuits that govern pain, social behaviors, thirst, food consumption, reward and attention, as well as circuits involved in memory, parenting behavior and psychiatric conditions such as obsessive-compulsive disorder and schizophrenia.
Patrick A. Forcelli, a professor of pharmacology and physiology at Georgetown University, said the technique ushered in a "golden era" for neuroscience and has become a mainstay of nearly every lab that studies brain circuits. "You can't do systems neuroscience today without relying on these tools," he said.
Hope for treatments
The committee said the research is already providing insights into brain disorders. Animal models are being used to study schizophrenia, Alzheimer's disease, Parkinson's disease, epilepsy and addiction — conditions that affect millions of people and have limited treatment options.
"There are mouse models of dementia, epilepsy, addiction. By understanding which cells are active in these diseases in mice, we can understand where to look in humans," Wedell said.
Researchers are also applying the technique to try to restore vision in people blinded by retinitis pigmentosa, a progressive eye disease that destroys the retina's rods and cones. Per Svenningsson, a professor of neurology at Karolinska, said optogenetics has been used to partially restore vision in blind patients with the condition by stimulating healthy cells that remain, activating the optic nerve and generating visual perception in the brain.
According to a Nobel committee release, when a channelrhodopsin-like protein was inserted into the retina of a blind person, the person regained some vision and, using special glasses emitting light, was able to discern and grasp objects on a table.
Another area of research seeks to use optogenetics to improve cochlear implants for hearing loss, potentially allowing more precise stimulation of the auditory nerve than current electrical devices.
Reuters reported that the most advanced treatments under development include an autism spectrum disorder therapy from US-based biotech company MapLight and a vision restoration medicine for retinitis pigmentosa from Nanoscope, also based in the United States. Both are still some time away from reaching patients.
Laureates surprised by the call
Perlmann said he reached the winners before the public announcement. "All three were very surprised," he said, adding that they each said the same thing — that they thought it was "absolutely wonderful" to receive the prize together, calling each other friends.
Deisseroth, who was up past midnight in California working on a paper and sending emails to students, said the news was "very surprising." He had just turned in and was starting to drift off when his phone began buzzing. In an interview shortly before 4 a.m. Pacific time, he said his children were still asleep and he planned to make their school lunch sandwiches in a few hours, as he did every morning.
Hegemann, who was born into a family of doctors, developed an early fascination with science and exploration. An enthusiast of astronomy and explorers such as Christopher Columbus, Fridtjof Nansen and Roald Amundsen, he said after winning the 2020 Shaw Prize that scientific research was akin to charting unknown territory.
Nagel, who was born in southern Germany, became seriously ill at age five and spent many summer holidays undergoing surgery. He later said, when receiving the 2020 Shaw Prize, that he loved mathematics, physics and biology as a child, worked as a teacher, opened a cafe and took up hang gliding in his spare time. He has said he first met Hegemann at the Max Planck Institute of Biophysics in Frankfurt.
Deisseroth, born in Boston in 1971, grew up drawn to both science and literature. Initially set on neurosurgery, he shifted to psychiatry after encountering suffering patients, asking why depression steals joy and what causes autism. He is a summa cum laude Harvard graduate who completed his PhD and MD at Stanford. He is a professor of bioengineering and psychiatry and behavioral sciences at Stanford and an investigator at the Howard Hughes Medical Institute.
What comes next
The medicine prize traditionally opens the annual Nobel announcements. The physics prize will be awarded Tuesday by the Royal Swedish Academy of Sciences in Stockholm, followed by chemistry on Wednesday and literature on Thursday. The Nobel Peace Prize will be announced Friday by the Norwegian Nobel Institute in Oslo, and the Nobel Memorial Prize in Economic Sciences will be awarded next Monday.
Last year's medicine prize went to Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi for discoveries of peripheral immune tolerance, the mechanism that explains how the immune system prevents rogue cells from attacking the body's own tissues and organs.