Nobel Prize in Medicine Goes to Trio Behind Optogenetics

The Nobel Assembly at Karolinska Institutet has awarded the 2026 Nobel Prize in Physiology or Medicine jointly to Karl Deisseroth of the Howard Hughes Medical Institute and Stanford University, Peter Hegemann of Humboldt University of Berlin, and Georg Nagel of the University of Würzburg, "for their discoveries concerning light-gated ion channels and optogenetics."

The prize honors optogenetics, a technique that allows researchers to switch nerve cells on and off using light, revealing how brain circuits shape memory, emotion and behavior in living animals. The discovery traces back to a single-celled alga and has since transformed neuroscience research worldwide.

The story began with Peter Hegemann's curiosity about how Chlamydomonas, a microscopic alga, swims toward light. In the early 2000s, Hegemann and Georg Nagel identified the protein responsible: channelrhodopsin, found on the alga's surface. When exposed to blue light, the protein opens a channel that lets charged ions flow into the cell, generating an electrical signal. Crucially, the pair found that any cell carrying this protein became sensitive to light.

Karl Deisseroth took the discovery further by inserting the gene for channelrhodopsin into rat nerve cells. Shining blue light on the cells triggered a nerve signal, a breakthrough he published in 2005. Two years later, he demonstrated the same light-controlled switch in the brains of living mice, effectively giving scientists a remote control for individual neurons.

"Optogenetics provides opportunities for mapping the brain in a way that we could once only dream of," said Per Svenningsson, chair of the Nobel Committee for Physiology or Medicine.

Before this work, researchers could observe which brain regions were active during certain behaviors but struggled to prove cause and effect. Optogenetics changed that by letting scientists directly turn specific neurons on or off and watch the results in real time. The method has since been used to map neural circuits linked to memory, emotion and behavior, with relevance to neurological and psychiatric disorders. In clinical research, scientists are also exploring its use to help restore vision in people with visual impairment.

Deisseroth, born in 1971, earned his Ph.D. in 1998 and M.D. in 2000, both from Stanford University, where he is now a professor of bioengineering and of psychiatry and behavioral sciences. Hegemann, born in 1954, completed his Ph.D. in 1984 at the Max Planck Institute for Biochemistry in Martinsried, Germany, where the prize-winning research was carried out; he now holds the Hertie Senior Professorship of Neuroscience at Humboldt University of Berlin. Nagel, born in 1953, earned his Ph.D. in 1988 at the University of Frankfurt and conducted the award-winning work at the Max Planck Institute for Biophysics in Frankfurt; he is now professor of molecular plant physiology at the University of Würzburg.

The laureates will share the prize sum of 12 million Swedish kronor equally.