The 2026 Nobel Prize in physiology or medicine has been awarded for pioneering work on optogenetics, a technology that enables scientists to investigate how nerve cells influence memories, emotions and behaviour in the living brain. Peter Hegemann, Georg Nagel and Karl Deisseroth have been recognised for discoveries that established the foundation of modern optogenetics and opened a new era in neuroscience. Hegemann and Nagel discovered channelrhodopsin, a light-sensitive protein found in a single-celled alga. Deisseroth subsequently transformed this protein into a light-controlled switch that allows researchers to activate specific nerve cells with precision.
Optogenetics Opens a New Window into the Brain
Scientists have long sought to understand how the brain controls emotions, behaviour and bodily functions. During the 20th century, researchers identified brain regions associated with different functions. However, existing techniques often could not establish whether specific nerve cells directly caused particular responses. As a result, scientists could develop only a broad “map” of brain function, leaving many causal connections unexplained. Optogenetics has changed this approach. The technique allows researchers to control selected nerve cells using light and observe the resulting effects, providing a more precise way to study neural circuits. “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.
Discovery of the Light-Sensitive Protein
The breakthrough began with Peter Hegemann’s interest in how Chlamydomonas, a single-celled alga, moves towards light. In the early 2000s, Hegemann and Georg Nagel discovered channelrhodopsin, a protein located on the surface of the algal cell. When exposed to blue light, the protein opens a channel that allows charged ions to enter the cell, generating an electrical impulse. Importantly, the researchers found that introducing channelrhodopsin into other types of cells could also make those cells responsive to light. This discovery provided the essential biological tool for developing optogenetics.
Deisseroth Turns Protein into a Neural Switch
Karl Deisseroth took the discovery a step further by introducing the gene responsible for channelrhodopsin
into rat nerve cells. When he illuminated these modified nerve cells with blue light, he successfully triggered nerve signals. He published the breakthrough in 2005 and, two years later, demonstrated that the light-controlled system could operate inside the brains of living mice. This work established the foundation for using light to control neural activity in living animals.
Optogenetics Transforms Brain Research
The technique became known as optogenetics and quickly gained global importance. Researchers can now use it to activate or inhibit specific neural circuits and study their roles in memory, emotions and behaviour. Consequently, optogenetics has helped scientists investigate neural mechanisms associated with several neurological and psychiatric disorders. Researchers are also exploring potential clinical applications. For example, optogenetic approaches are being investigated as a way to restore vision in people with visual impairment.
A New Era in Neuroscience
The work of Hegemann, Nagel and Deisseroth has fundamentally changed how scientists study the brain. By allowing researchers to manipulate specific nerve cells with light, optogenetics provides a powerful tool for connecting neural activity with behaviour. As per the nobelprize.org press release, as research continues, the technology is helping scientists uncover new insights into one of humanity’s greatest scientific questions: how the brain creates memories, emotions and behaviours.
