Nobel Prize in Medicine 2026 | Nobel Prize in Medicine for the inventors of optogenetics

Anna Wedell (front, l-r), Per Svenningsson, Abdel El Manira and the Secretary of the Nobel Assembly of the Stockholm Karolinska Institute, Thomas Perlmann, at the announcement of the Nobel Prize winners in Physiology or Medicine, Karl Deisseroth, Peter Hegemann, Georg Nagel, who are pictured on a display, at the Karolinska Institute. Photo: dpa/Steffen Trumpf Almost 20 years ago, Karl Deisseroth's group at Stanford University succeeded in controlling the behavior of laboratory mice using light signals in the brain. They were able to specifically get the mice to move their whiskers or wake them from sleep. Since then, laboratories around the world have been experimenting with the underlying method, called optogenetics, awakening frightening memories in the test animals or making them forget all fear and much more. Introducing certain genes into the brains of mice makes it possible to switch nerve signals on or off using light.

The American Karl Deisseroth and the two Germans Peter Hegemann and Georg Nagel will receive the Nobel Prize for Physiology or Medicine this year "for their discoveries in the field of light-controlled ion channels and optogenetics," the product of which is this process.

Although the externally controlled mice briefly attracted media attention, the experiments are primarily about developing a better understanding of how neuronal processes work - so they are basic research. Functional maps of the brain can now be created, explained Anna Wedell, professor at the Karolinska Institute, when announcing this year's laureates.

»The technique of optogenetics, for the development of which Deisseroth, Hegemann and Nagel were honored, enables the targeted research of individual neuronal circuits in animal models. Over the past 20 years, amazing insights have been gained about mental illnesses, such as behavioral changes, the reward system or fear circuits," comments Sebastian Walther, Director of the Clinic for Psychiatry, Psychosomatics and Psychotherapy at the University Hospital of Würzburg. Georg Nagel also recently worked at the University of Würzburg.

However, the mouse brain that can be stimulated with optical signals is the result of several groundbreaking discoveries by this year's three laureates in the field of medicine. It all started with single-celled algae, which Peter Hegemann, who at the time worked at the Max Planck Institute for Biochemistry in Martinsried, observed. The alga Chlamydomas is able to swim extremely quickly to a light source. A small eyespot on the cell surface ensures that it perceives light, which Hegemann further investigated. He discovered that Chlamydomas responded to light 20 times faster than the human eye.

Together with Georg Nagel, who conducted research at the Max Planck Institute for Biophysics in Frankfurt, Hegemann investigated the question of what was behind this rapid reaction. They discovered a protein produced by the algae that functions as an ion channel, a way of transmitting signals. (The discovery of ion channels was also a breakthrough in the understanding of living organisms, for which Erwin Neher and Bert Sakmann were awarded the Nobel Prize in Medicine in 1991.)

»The technique of optogenetics enables the targeted research of individual neuronal circuits in animal models.«

Hegemann and Nagel were able to isolate a light-sensitive protein, which they named channelrhodopsin (English: Channelrhodopsin). When they introduced the DNA for this protein into the cells of other organisms, they also became receptive to light signals. This is where neuroscientist Karl Deisseroth came into play, who was looking for a protein to trigger electrical impulses in nerve cells. When he heard about channelrhodopsin, he asked Georg Nagel for the DNA of this protein. With this, his research group succeeded in controlling the activity of nerve cells in living animals in 2005.

Even if nerve control via light signals from outside (or inside, because a fiber optic cable is still inserted into the brain of the test mice) sounds like Orwell's "1984" to laypeople - when it comes to humans, optogenetics has so far hardly had any approaches to practical medical application. In order for nerve cells to be manipulated with light at all, they would first have to be genetically modified so that the cells are able to produce channelrhodopsin. In order to affect certain neurological diseases such as Parkinson's, but also severe depression or addictions, optogenetics only offers more precise information about which neuronal networks are involved, but no direct therapy options.

The Karolinska Institute names two specific therapeutic approaches for optogenetics: the restoration of part of the vision in the eye disease retinitis pigmentosa and the improvement of cochlear implants for the deaf or severely hearing impaired.

»If the natural light-sensitive photoreceptors are lost, other nerve cells in the retina can be preserved. These should be made sensitive to light using optogenetic methods and thus take over part of the function of the lost photoreceptors," writes the University of Bonn about a possible future treatment of retinitis pigmentosa. A team led by Volker Busskamp in Bonn is developing optogenetic methods for researching degenerative retinal diseases. Retinal organoids ensure that research on laboratory animals no longer needs to be carried out.

With cochlear implants, the auditory nerve is stimulated with electrical signals according to the current state of technology. With optogenetics, the signals could be transmitted using light and more precisely. However, the prerequisite would be gene therapy that allows the auditory nerve to produce the light-sensitive protein. The first clinical studies on this are planned at the University Medical Center Göttingen.

Karl Deisseroth, born in 1971, is a professor of biotechnology, psychiatry and behavioral research at the Howard Hughes Medical Institute and Stanford University in the USA. Peter Hegemann, born in 1954, is senior research professor of neuroscience at the Institute of Biology at the Humboldt University in Berlin. In 1984 he received his doctorate at the Max Planck Institute for Biochemistry in Martinsried. Georg Nagel, born in 1953, was professor of molecular plant physiology and then senior professor at the Julius Maximilian University of Würzburg (JMU) until the end of June 2026. The award-winning work dates back to his time as a research group leader at the Max Planck Institute for Biophysics until 2004.

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