Three scientists whose work transformed the study of the brain have been awarded the 2026 Nobel Prize in Physiology or Medicine for discoveries that made it possible to control nerve cells using light. Stanford professor Karl Deisseroth shares the prize with German researchers Peter Hegemann of Humboldt University of Berlin and Georg Nagel of the University of Würzburg. The Nobel Assembly recognised their discoveries concerning light-gated ion channels and optogenetics.
Their work has given neuroscientists an unprecedented tool for investigating how individual nerve cells and neural circuits influence behaviour, emotions, memories and other functions of the brain. Instead of simply observing brain activity, researchers can use light to activate or inhibit precisely selected groups of neurons and then study the resulting effects.
The breakthrough began with research into light-sensitive proteins known as channelrhodopsins. Hegemann and Nagel helped establish how these proteins, originally discovered in single-celled algae, could respond to light by allowing charged particles to pass through cell membranes. Their discoveries provided the biological foundation for controlling electrical activity with light.
Deisseroth subsequently played a central role in developing optogenetics as a practical neuroscience technique. By introducing light-sensitive proteins into selected nerve cells and using precisely controlled light pulses, researchers can manipulate specific neural populations while recording how the rest of the nervous system responds.
The technique has changed how scientists investigate neurological and psychiatric disorders because it allows them to examine particular neural circuits with a level of precision that was previously difficult to achieve. Researchers can investigate circuits associated with conditions including depression, anxiety, addiction and other disorders, helping to reveal how changes in specific networks can influence behaviour.
Optogenetics has also become an important research tool for understanding how the brain works normally. Scientists can investigate which groups of neurons are involved in particular behaviours and determine how different parts of the nervous system communicate. The approach has helped move neuroscience beyond simply mapping brain activity toward experimentally testing the role of individual neural circuits.
The Nobel Committee described the discoveries as enabling researchers to demonstrate how particular nerve cells influence functions such as memories, feelings and behaviour. The work has therefore provided a powerful bridge between molecular biology and the study of complex brain functions.
The 2026 award highlights how a discovery involving a light-sensitive protein from algae ultimately became one of the most influential technologies in modern neuroscience. Although optogenetics remains primarily a research technique, scientists are also investigating its potential medical applications, including approaches that could eventually help treat neurological conditions or restore functions such as vision.
For Deisseroth and his fellow laureates, the Nobel recognition marks the culmination of decades of research into how nerve cells communicate and how their activity can be controlled. Their work has given scientists a new way to investigate the brain at the level of individual cells and circuits, opening new possibilities for understanding some of the most complex disorders affecting the human nervous system.
