The 2026 Nobel Prize in Physiology or Medicine is awarded to Karl Deisseroth, Georg Nagel and Peter Hegemann for their discoveries underpinning the field of optogenetics, the ability to control cells using light and genetics.
Optogenetics allows scientists to use light to switch cells on and off. Using light-sensing proteins called rhodopsins, optogenetics enables precise targeting of cells, such as brain cells, to understand what they do.
The technique has revolutionized neuroscience by opening up the brain’s activity to scientists in ways previously impossible. As Deisseroth explained in Scientific American in a 2010 article, the brain is of such great complexity, that “neuroscientists lack a deep grasp of what the brain is really doing—of how specific activity patterns within specific brain cells ultimately give rise to thoughts, feelings and memories.”
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Optogenetics reveals how specific neurons and neural pathways govern behavior, such as eating, sociability and aggression. Controlling and monitoring individual cells has also illuminated neurological diseases, such as Parkinson’s and epilepsy.
Deisseroth had just begun to drift off to sleep when he got the call late at night that he’d won the prize, he recalls in an interview with Scientific American immediately after the prize was announced. “I had a hard time forming words,” he says. “I was so surprised and discombobulated. But it was, of course, very delightful and exciting.”
Understanding how our bodies function and dysfunction at a cellular level allows researchers to address those problems, Deisseroth says. “What we’re doing now—and many others as well—is we’re seeing how can we leverage this precision to find new treatments, new medications, new neuromodulator approaches that build on this foundation of causality.”
Abdel El Manira, a distinguished professor at the Karolinska Institute in Sweden and a member of the Nobel committee, said at the prize announcement that optogenetics' impacts extend beyond our understanding of the healthy brain.
“It has also helped reveal how specific brain circuits are disrupted, with implications for conditions such as blindness, depression, addiction and dementia. Yet despite these extraordinary advances, the brain still holds countless mysteries, with much more left to learn and discover, and optogenetics has given us a powerful means to take on these challenges.”
The work builds on an idea proposed by 1962 Nobel winner and molecular biologist Francis Crick, who suggested light might be the key to controlling specific cells, El Manira explained. “This was a brilliant idea, but it seemed entirely far-fetched,” he said. To better understand how this might work, researchers studied algae called Chlamydomonas, which respond to light by swimming toward it. Through a series of experiments, Hegemann and Nagel discovered that rhodopsin proteins were central to the process. Deisseroth then applied the findings to neurons in mammals.
Looking to the future, scientists believe optogenetics could hold therapeutic applications. For example, some early clinical trial work suggests optogenetic therapy could help restore sight in people with retinitis pigmentosa, an inherited form of progressive vision loss that causes light-sensing cells in the eye to die. Clinicians can inject DNA encoding for a light-sensing protein into retinal neurons, enabling them to activate and send electrical signals to the brain when exposed to light—bypassing the dead and damaged cells.
Deisseroth is a professor at Stanford University, Hegemann is a professor at Humboldt University of Berlin, and Nagel is a professor at the Julius Maximilian University of Würzburg in Germany. The award-winning work was done at Stanford, the Max Planck Institute for Biochemistry in Martinsried, Germany, and the Max Planck Institute for Biophysics in Frankfurt.
The Nobel Prize in Physiology or Medicine, first given in 1901, has been awarded 117 times to 235 winners for innovations in medicine and biological sciences. Over the years, these have included the discovery of insulin, penicillin, blood groups and the molecular structure of DNA, and the understanding of biological processes such as how neurons work, malaria spreads and human papilloma viruses cause cervical cancer, as well as treatments such as in vitro fertilization and the first antibiotic for tuberculosis.
In recent years, laureates have won the prize for their role in research leading to the development of the mRNA vaccine for COVID-19, awarded in 2023, the discovery of “microRNA,” or small RNA molecules that help decipher our DNA, in 2024 and peripheral immune tolerance, or how the immune system helps regulate itself, in 2025.
To celebrate the award, Deisseroth says he plans, fittingly, to get back to his research. “We’ve got a lot of things we want to discover and a lot of people we want to help.”
Editor’s Note (10/5/26): This is a breaking news story and will be updated.