Three scientists have been awarded the 2026 Nobel Prize in Physiology or Medicine for a breakthrough technique that turns algal proteins into switches for nerve cells.
On October 5 local time, the Karolinska Institute in Sweden announced that the 2026 Nobel Prize in Physiology or Medicine would be awarded to American scientist Karl Deisseroth and German scientists Peter Hegemann and Georg Nagel in recognition of their discoveries concerning light-gated ion channels and optogenetics. The three will share the prize money of 12 million Swedish kronor (approximately 8.0169 million yuan). Per Svenningsson, chairman of the Nobel Committee for Physiology or Medicine, said that optogenetics offers a way of mapping the brain that we could once only dream of. As people have put it, the contributions of these scientists have heralded the arrival of a new era in neuroscience.
Optogenetics enables scientists to precisely switch the activity of individual nerve cells on and off within a living brain, thereby revealing how neural circuits shape memory, emotion and behavior. At present, the method has been widely used in laboratories around the world and has been attempted in clinical settings to restore vision in visually impaired patients.
From Algae to the Brain: The Origins of a Discovery
The starting point of this research came from Peter Hegemann's curiosity about a seemingly simple question: how does the single-celled alga Chlamydomonas sense a light source and swim toward the light? Peter Hegemann began his research with this curiosity. In the early 21st century, together with Georg Nagel, he discovered an algal protein called channelrhodopsin, which is distributed on the cell surface. When illuminated by blue light, the channel inside the protein immediately opens, charged ions flood into the cell and generate an electrical signal. More critically, the two found that no matter which cell type this protein was introduced into, that cell would become sensitive to light. In 2003, a team led by Nagel, Hegemann and Professor Ernst Bamberg further confirmed that channelrhodopsin-2 (ChR2) expressed in animal cells could indeed regulate the movement of ions in and out under the action of light, and pointed out in their paper that the technique could become "a powerful tool."
Hegemann is currently affiliated with Humboldt University of Berlin in Germany, and the discovery related to his award was completed at the Max Planck Institute of Biochemistry in Martinsried, Germany. Nagel is now a professor of molecular plant physiology at the University of Würzburg in Germany, and the related discovery was completed at the Max Planck Institute of Biophysics in Frankfurt. The two were born in 1954 and 1953, respectively.
Deisseroth's Key Translation: From Protein to Neural Switch
It was American scientist Karl Deisseroth who pushed this basic discovery toward practical application. After reading the aforementioned paper, Karl Deisseroth, then a postdoctoral fellow at Stanford University, and doctoral student Edward Boyden quickly established cooperation with Nagel's team and set out to introduce ChR2 into neurons. Deisseroth solved the core problem of stable expression of ChR2 on the nerve cell membrane, while Boyden developed a fiber-optic system capable of precisely controlling light. At 1 a.m. on August 4, 2004, Boyden applied blue light stimulation to neurons expressing ChR2 under a microscope, and the first neuron tested immediately produced a stable action potential within milliseconds. That night, the prototype of modern optogenetics was declared born. He published this breakthrough result in 2005. Two years later, he further achieved the goal of controlling nerve cells with light in the brains of living mice, marking the official entry of optogenetics into the stage of experimental application.
Deisseroth was born in 1971 and received his Ph.D. and M.D. from Stanford University in the United States in 1998 and 2000, respectively. He currently serves as the D.H. Chen Professor at the Howard Hughes Medical Institute and Stanford University, and his research covers bioengineering, psychiatry and behavioral sciences.
Clinical Prospects and a New Era in Neuroscience
Since then, the field of optogenetics has shown explosive development. Moreover, the significance of optogenetics has gone beyond basic research and is extending toward clinical medicine: in December 2005, the joint team of Nagel and Professor Alexander Gottschalk used optogenetics for the first time to alter the behavior of nematodes; in 2006, Professor Pan Zhuohua's research group enabled mice with retinal disease to regain responses to light; in 2007, Professor Feng Guoping's research group reported a transgenic mouse system stably expressing ChR2-YFP. With this technique, researchers have been able to reveal the neural circuits behind specific memories, emotions and behaviors related to neurological and psychiatric disorders. At the clinical level, researchers are trying to use this method to restore visual function in patients with impaired vision.
The term "optogenetics" itself did not first appear in an academic paper until 2006, but related research has rapidly swept through laboratories around the world. The Karolinska Institute noted in its announcement that optogenetics has "fundamentally changed our understanding of the brain," with new discoveries emerging every day to help humanity unravel the ultimate puzzle of how the brain works. The Nobel Committee characterized the contributions of the three laureates as "laying the foundation for a new era in neuroscience." The award ceremony will be held in Stockholm on December 10, as is customary.