The three researchers are honored for discoveries about light-controlled ion channels and optogenetics, a method that allows researchers to control the activity of individual nerve cells in a living brain using light. Deisseroth works at the Howard Hughes Medical Institute and Stanford University in the US, Hegemann at Humboldt University Berlin, and Nagel at University of Würzburg. The laureates share the prize money of 12 million Swedish kronor equally and will receive their awards on December 10, the anniversary of Alfred Nobel's death, in Stockholm and Oslo.
Discovery began in the early 1990s
The work traces back to a question Peter Hegemann asked himself in the early 1990s at the Max Planck Institute: How does a single-celled green alga Chlamydomonas navigate toward light? According to the Nobel Committee's background description, he suspected that a single protein complex could both sense light and function as an ion channel, but this met with skepticism because no known ion channel could respond to light. Around the turn of the millennium, after years of setbacks, his group found two genes resembling known blueprints of light-sensing proteins. Together with Georg Nagel, Hegemann showed that the protein channelrhodopsin is a channel: when blue light hits it, the channel opens and allows charged ions to flow into the cell, generating an electrical impulse. The protein functioned regardless of which cell type it was introduced into.
According to the Nobel Committee, Karl Deisseroth inserted the channelrhodopsin gene into nerve cells of rats and triggered a nerve signal with blue light. He published this breakthrough in 2005. Two years later, the light-controlled switch worked in the brains of living mice. The new method received the name optogenetics in 2006 and is now used in laboratories worldwide.
What light can reveal in the brain
With optogenetics, researchers can uncover neural circuits that control memories, emotions, and behavior, and are relevant to neurological and psychiatric diseases, the Nobel Committee explained. In one experiment, a research group examined mice's brains during a frightening experience and later reactivated those nerve cells that apparently formed the memory. The animals subsequently showed fear responses even though they were not in danger, which the committee noted was the first experiment to identify the nerve cells necessary for a specific memory with such precision. Committee chairman Per Svenningsson said optogenetics opens possibilities for mapping the brain that researchers previously could only dream of.
Clinical application: restoring sight in retinal disease
One clinical application of optogenetics involves people with vision impairment. Researchers are attempting to restore vision in retinitis pigmentosa, an inherited disease that destroys the light-sensitive cells of the retina. Doctors can inject DNA carrying the blueprint for a light-sensitive protein into retinal nerve cells so that they emit electrical signals to the brain when exposed to light, bypassing damaged and dead cells.
Benjamin Bakall reported on REMAIN follow-up data from a larger study at the 2026 annual meeting of the American Society of Retina Specialists. In the Phase 2b/3 RESTORE trial, 27 patients received a high or low dose of the drug MCO-010 or sham treatment. After approximately three years, the median improvements in visual acuity in the treatment groups persisted. Patients reported they could now recognize cutlery on a table or perceive passing cars. No serious adverse events related to treatment occurred according to the presented data. Bakall called the therapy a durable option for patients with advanced disease, but cautioned against overpromising.
Deisseroth himself recommended in a 2023 interview to first conduct thorough basic research in animals and evolutionarily conserved brain structures before experimenting in humans. Bakall urged caution when presenting the RESTORE data and warned against offering false hope to patients with advanced retinitis pigmentosa.