Who is Nobel winner Karl Deisseroth? And all about optogenetics that could restore sight in visually impaired people

The 2026 Nobel Prize in Physiology or Medicine has been awarded jointly to Karl Deisseroth, Peter Hegemann, and Georg Nagel. It was announced by the Nobel Assembly at Karolinska Institutet on October 5, 2026. The institute recognized their contributions that have significantly advanced the field of neuroscience.

Who is Karl Deisseroth

Born in 1971, Karl Deisseroth is the D.H. Chen Professor and Professor of Bioengineering and of Psychiatry and Behavioral Sciences at Stanford. Deisseroth earned his Ph.D. in 1998 and MD in 2000 from Stanford University. He is also known for inventing hydrogel-tissue chemistry. He is also a member of US National Academy of Engineering, US National Academy of Sciences and the US National Academy of Medicine.

All about optogenetics

Optogenetics is a technique that allows scientists to study how nerve cells shape memories, emotions and behaviour in the living brain. “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.


It all started when Hegemann wondered about how Chlamydomonas, a single-celled alga, is able to swim towards a light source. In the early 2000s, Hegemann and Nagel discovered channelrhodopsin, an algal protein located on the cell surface.

When exposed to blue light, the protein opens a channel that allows charged ions to flow into the cell, creating an electrical impulse. The researchers found that when the protein was introduced into other types of cells, those cells could also be made sensitive to light.

Deisseroth took the discovery a step further by introducing the gene for channelrhodopsin into rat nerve cells. When the modified cells were exposed to blue light, he was able to trigger nerve signals. He published the breakthrough in 2005.

In 2007, Deisseroth demonstrated that the light-controlled switch could also work inside the brains of living mice. This technique for controlling nerve activity with light became known as optogenetics.

The method has since had a major impact on neuroscience. Researchers have used optogenetics to identify neural circuits involved in specific memories, emotions and behaviours, including those associated with neurological and psychiatric disorders.

The technique is also being explored for potential medical applications. Researchers are using optogenetics in attempts to restore sight in people with visual impairment.

Optogenetics has fundamentally changed scientists’ understanding of the brain. By allowing researchers to control and observe the activity of specific nerve cells with light, the technique has opened new ways to investigate one of humanity’s greatest mysteries: how the brain works.