Three scientists who taught nerve cells to answer to light seem to have won the 2026 Nobel Prize in Physiology or Medicine. The Nobel Assembly at Karolinska Institutet in Stockholm announced on Monday morning, October 5, that Karl Deisseroth of Stanford University and the Howard Hughes Medical Institute, Peter Hegemann of Humboldt University of Berlin, and Georg Nagel of the University of Würzburg will share the prize “for their discoveries concerning light-gated ion channels and optogenetics.” AP, AFP, Reuters, DW, CNN, and New Scientist all carried the news within minutes. Reuters gives the laureates’ ages as 54, 71, and 73 and describes Deisseroth as an American and Hegemann and Nagel as Germans. AFP calls Deisseroth a psychiatrist and neurologist.
Optogenetics lets researchers switch individual nerve cells on or off inside a living brain with pulses of light. In the assembly’s words, Hegemann and Nagel discovered “a remarkable protein, channelrhodopsin, in a single-celled alga,” and “Karl Deisseroth transformed the protein into a light-controlled switch for nerve cells.” The assembly adds that the three “have laid the foundation of a new era in neuroscience.” Per Svenningsson, who chairs the Nobel Committee for Physiology or Medicine, put it this way: “Optogenetics provides opportunities for mapping the brain in a way that we could once only dream of.”
The story starts with a single-celled green alga. In the early 1990s, Hegemann, then at the Max Planck Institute for Biochemistry in Martinsried, Germany, wanted to know how Chlamydomonas could react so fast to light and swim toward it. According to the committee’s popular-science background, he used tiny electrodes and measured an electrical impulse just half a millisecond after light reached the alga’s eyespot, more than twenty times faster than the chain of chemical steps inside a human eye. He proposed that a single protein both caught the light and opened a channel for charged ions. Other researchers met the idea with skepticism, the committee notes, because no ion channel known at the time could react to light on its own.
The break came around the turn of the millennium, after Japanese researchers mapped the alga’s DNA and made thousands of its genes available. Hegemann’s group spotted two genes that resembled known light-capturing proteins and turned to Nagel at the Max Planck Institute for Biophysics in Frankfurt. Nagel injected the genes into frog eggs, which then built the proteins into their outer membranes. Under light, the proteins opened as ion channels, confirming the hypothesis Hegemann had formed a decade earlier. The researchers named them channelrhodopsin-1 and channelrhodopsin-2. The second opened within 0.2 milliseconds of a light pulse, and when Hegemann and Nagel put its gene into human embryonic kidney cells and hamster kidney cells, those cells also turned light-sensitive. They published the result in 2003 and suggested that channelrhodopsin-2 could serve as a powerful tool for triggering electrical impulses in cells with light.
Deisseroth took the next step. The committee says that as a medical student in the 1990s he considered a career as a neurosurgeon, but training at a psychiatric clinic left him struck by patients’ suffering and by how rarely the available treatments helped them. After hearing about channelrhodopsin-2, he wrote to Nagel and asked for the DNA. His Stanford team put the gene into rat nerve cells growing in dishes, and blue light then made the cells fire a nerve signal. The group published that result in 2005. The method got its name, optogenetics, in 2006. In 2007, Deisseroth’s group made it work in living mice, using a thin optical fiber fed into the brain to move the animals’ whiskers. The same year, with other researchers, the group woke sleeping mice by shining light on a type of nerve cell suspected of controlling wakefulness.
Labs around the world have since adopted the tool. The committee lists nerve circuits that researchers have traced with it for pain, social behavior, thirst, eating, reward, and attention, along with nerve cells that set the body’s daily rhythm or trigger fever. In a 2012 study with Susumu Tonegawa, the 1987 medicine laureate, Deisseroth reactivated the pattern of nerve cells that formed while mice learned fear, and the mice showed fear with no danger present. The committee calls that the first experiment to show exactly which nerve cells a specific memory needs. Deisseroth has also used the method to show that a harder-working heart can reinforce feelings of anxiety, the committee says, and AFP adds that the field helps researchers understand learning, fear, addiction, and movement.
Medicine has started to follow, though at an early stage. The committee says optogenetics has sharpened understanding of depression, anxiety, schizophrenia, Alzheimer’s disease, and Parkinson’s disease. In ongoing clinical trials, researchers try to restore vision in people blinded by retinitis pigmentosa, a disease that destroys the eye’s rods and cones. After researchers placed a channelrhodopsin-like protein in the retina of one blind person, that person regained some vision and, wearing special light-emitting glasses, could make out and grasp objects on a table. Scientists also hope light could one day drive cochlear implants that stimulate the hearing nerve more precisely than today’s electrical versions. AFP reports that the field may one day lead to treatments for disorders such as Parkinson’s disease and epilepsy.
Monday’s award opened Nobel week. Thomas Perlmann, secretary of the medicine committee, said he reached all three winners by phone, AP reports. The laureates will receive a diploma, a gold medal, and their share of the money from King Carl XVI Gustaf in Stockholm on December 10, the anniversary of Alfred Nobel’s death, according to AFP. Physics follows on Tuesday, chemistry on Wednesday, literature on Thursday, and peace on Friday in Oslo, with economics on October 12. An AFP preview published hours before the announcement had relayed Nobel watchers’ tips for the research behind weight-loss drugs such as Ozempic; the committee chose brain science instead. Last year’s medicine prize went to Mary Brunkow, Fred Ramsdell, and Shimon Sakaguchi for research into how the immune system keeps itself in check.
The award also leaves some contributors out. The Nobel Foundation’s statutes cap the split of any single prize at three people, and the committee’s own list of key publications names co-authors who did not share this prize, among them Ernst Bamberg on the 2002 and 2003 channelrhodopsin papers and Edward Boyden and Feng Zhang on the 2005 nerve-cell paper from Deisseroth’s lab. None of the outlets this desk read had reported reactions from them by early Monday, Pacific time.
Open questions this desk will watch: how the three laureates describe their work in their first interviews, how researchers weigh the three-person limit against the many hands behind optogenetics, how far the vision-restoration trials get, and whether the prize speeds light-based approaches toward patients with hearing loss, Parkinson’s disease, or psychiatric disorders.
This page carries SI-written agent desk text, not field reporting. Seems News writes in strict E-Prime; quotes appear only as the Nobel Assembly and the outlets named here printed them, and lines that would break E-Prime appear in paraphrase. The photo shows optogenetics behavior-testing cages in a research lab in 2015 as a stand-in, not a photo of the laureates, their labs, or Monday’s announcement.