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Karl Deisseroth of the United States and Germans Peter Hegemann and Georg Nagel have jointly won the 2026 Nobel Prize in Physiology or Medicine for discoveries that laid the foundation for optogenetics, a technique that has transformed scientists’ ability to investigate and control individual nerve cells.
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The Nobel-winning work allows researchers to use light, combined with genetic modification, to switch selected brain cells on or off.
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Hegemann and Nagel’s early research into single-celled algae led to the discovery and characterisation of channelrhodopsin, a light-sensitive protein. Deisseroth and other researchers subsequently helped turn that discovery into a practical method for controlling neurons with precisely timed pulses of light.
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Optogenetics has helped scientists investigate neurological and psychiatric disorders, including Parkinson’s disease, epilepsy, depression, addiction, dementia and blindness.
October 05, (THEWILL) – German and United States scientists have been jointly awarded the 2026 Nobel Prize in Physiology or Medicine for pioneering work that has revolutionised the ability to study and control the brain.
Karl Deisseroth, 55, a professor at Stanford University and investigator with the Howard Hughes Medical Institute, and German scientists Peter Hegemann, 72, of Humboldt University in Berlin, and Georg Nagel, 73, of the University of Würzburg, were announced as the joint laureates on Monday.
They were honoured for their discoveries concerning light-gated ion channels and optogenetics, a breakthrough that enables scientists to use light to activate or silence specific cells.
The Nobel Committee said their work has provided researchers with an unprecedented tool for investigating how individual nerve cells and neural circuits control functions including movement, emotions, memory and behaviour.
At the heart of the breakthrough are light-sensitive proteins known as rhodopsins.
These proteins respond to light by controlling the movement of electrically charged particles, or ions, across cell membranes. Through genetic engineering, scientists can introduce the genes responsible for these proteins into selected neurons, effectively making the cells sensitive to light.
Once the neurons have been modified, researchers can use pulses of light to turn them on or off and then observe the resulting changes in brain activity and behaviour.
The precision of the technique represents a major advance over traditional methods of manipulating brain activity, such as drugs and electrical stimulation, which can affect large populations of cells or broader areas of the brain.
From Algae To Human Brain
The story behind the Nobel-winning discovery began with the study of microscopic organisms.
Hegemann and Nagel investigated how single-celled algae respond to light. Their research led to the discovery and characterisation of channelrhodopsin, a light-sensitive protein that allows the organisms to detect and respond to light.
The scientists found that the protein could also function when introduced into other cells. That finding opened the possibility of making selected cells responsive to light through genetic modification.
Researchers subsequently began exploring how the mechanism could be applied to nerve cells.
Deisseroth played a central role in developing the technique into a practical neuroscience tool, helping combine light-sensitive proteins with genetic techniques so that individual groups of neurons could be controlled with flashes of light.
The resulting method became known as optogenetics, combining optical technology with genetics. It has since become one of the most important tools in modern neuroscience.
Unlocking Brain’s Hidden Circuits
The human brain is made up of billions of interconnected nerve cells, creating an extraordinarily complex network responsible for thought, emotion, memory, movement and behaviour.
For decades, scientists could observe patterns of brain activity but often struggled to establish precisely which neurons caused particular functions.
Scientists can now genetically identify specific populations of neurons and make them responsive to light. By activating or suppressing those cells, researchers can examine how changes in their activity affect an animal’s behaviour or physiological responses.
The technique has helped scientists investigate neural circuits associated with eating, movement, sociability, aggression and other behaviours. It has also offered new insights into how brain circuits become disrupted by disease.
Abdel El Manira, a distinguished professor at the Karolinska Institutet and member of the Nobel Committee, said optogenetics had helped reveal how specific brain circuits are altered in conditions including blindness, depression, addiction and dementia.
Despite the progress, he said the brain still holds countless mysteries, with optogenetics providing scientists with a powerful method for addressing them.
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Potential To Transform Treatment
The significance of the Nobel-winning research extends beyond basic neuroscience.
Scientists are examining whether the ability to precisely control cells with light can eventually be translated into treatments for neurological and sensory disorders.
One promising area is retinitis pigmentosa, an inherited eye disorder in which light-sensitive cells in the retina gradually die, leading to progressive vision loss.
Researchers are investigating whether genetic material encoding light-sensitive proteins can be delivered into surviving retinal cells.
If successful, the modified cells could respond to light and generate electrical signals that travel to the brain, potentially bypassing damaged photoreceptor cells.
Early clinical research has demonstrated the potential of optogenetic approaches to restore some visual function, although the technology remains experimental and faces considerable scientific and medical challenges.
The principles are also being investigated in disorders in which abnormal patterns of neural activity contribute to disease.
The ability to target specific circuits could, in the future, provide a more precise approach to treating conditions in which conventional drugs affect many parts of the nervous system.
A New Era In Neuroscience
The Nobel-winning research was carried out at leading institutions in the United States and Germany, including Stanford University, the Max Planck Institute for Biochemistry and the Max Planck Institute for Biophysics.
The award recognises not merely a discovery about how cells respond to light, but the creation of a technology that has fundamentally altered the study of the brain.
The Nobel Prize in Physiology or Medicine, first awarded in 1901, has recognised discoveries that transformed medical science, including insulin, penicillin, blood groups and the molecular structure of DNA.
Previous laureates have also been recognised for discoveries concerning how neurons work, how malaria spreads, the role of human papillomaviruses in cervical cancer and the development of in vitro fertilisation.
In recent years, the prize has recognised research connected to mRNA vaccines, small RNA molecules and the mechanisms by which the immune system regulates itself.
The 2026 award highlights the growing ability of science to probe the brain at the level of individual cells.
What began with the study of light-sensitive proteins in microscopic algae has developed into a technology capable of switching selected neurons on and off with remarkable precision.
For neuroscience, the breakthrough has provided a new window into how neural circuits generate memory, emotions, movement and behaviour. For medicine, it has opened the possibility that the same precision could eventually be harnessed to correct abnormal cellular activity and treat some of the most difficult neurological and sensory disorders.
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