Optogenetics is a neuroscience tool fundamentally changing our understanding of the brain by demystifying how its neural circuits function—it uses light to control brain cells genetically engineered to respond to specific wavelengths.

The 2026 Nobel Prize in Physiology or Medicine jointly honors the work of Karl Deisseroth, a professor of bioengineering and psychiatry and behavioral sciences at the Howard Hughes Medical Institute and Stanford University; Peter Hegemann, a senior professor of neuroscience at Humboldt University in Germany; and Georg Nagel, a professor of molecular plant physiology at the University of Würzberg in Germany.

During the early 2000s, Hegemann and Nagel discovered channelrhodopsin, a light-sensitive protein from algae. When illuminated via blue light, a channel opens through the protein and charged ions flow into it, which creates an electrical impulse. And the bioengineered protein works within any brain cell—making it light sensitive.

In 2005, Deisseroth inserted the gene for channelrhodopsin into nerve cells from rats, illuminated the cells via blue light, and triggered a nerve signal. A few years later, this light-controlled “switch” was demonstrated inside the brains of living mice.

Optogenetics is a key neuroscience tool today—it’s enabled researchers to discover and map neural circuits governing specific memories, feelings, and behaviors relevant for neurological and psychiatric disorders.

Back in 2011, I wrote a cover story for OPN about the early days of optogenetics and fully expected to see the pioneers’ work win a Nobel Prize one day. If you’d like to explore it more: https://opg.optica.org/directpdfaccess/de989e01-db1a-409a-911f5f265ac447de_219553/opn-22-7-26.pdf?da=1&id=219553&seq=0&mobile=no.