Nobel medicine prize 2026 honours trio who gave brain scientists a light switch

New Delhi: An American scientist and two German researchers have won the 2026 Nobel prize in physiology or medicine for discoveries that allow scientists to control selected nerve cells with light, opening new ways to investigate how the brain works. Karl Deisseroth, Peter Hegemann and Georg Nagel were named on Monday, for developing the foundations of optogenetics, a technique that helps researchers establish how particular brain circuits influence memory, emotions and behaviour.

The Nobel assembly at Karolinska Institutet in Stockholm recognized the scientists “for their discoveries concerning light-gated ion channels and optogenetics”. They will share equally the prize money of 12 million Swedish kronor, approximately $1.2 million, as this year’s Nobel announcement week gets under way.

Deisseroth, 54, works at Stanford University in the United States, while Hegemann, 71, is based at Humboldt University of Berlin and Nagel, 73, at the University of Wurzburg. Their discoveries connect research on microscopic algae with a central challenge in neuroscience: determining what individual groups of nerve cells actually do within the brain’s densely interconnected networks.

The significance of optogenetics lies in the control it gives researchers over their experiments. By making chosen cells sensitive to light, scientists can activate or suppress their activity at specific moments and examine the consequences, helping distinguish a circuit that causes a response from one that merely becomes active alongside it.

The work began with investigations into how a single-celled green alga detects and responds to light. Hegemann and Nagel identified channelrhodopsins, proteins that act as light-sensitive channels in the cell membrane, allowing electrically charged particles to pass through when illuminated.

This provided a molecular mechanism through which light could change a cell’s electrical activity. In 2003, the researchers demonstrated that channelrhodopsin-2 could function in human cells, establishing that its usefulness extended beyond the organism in which it had been discovered.

Deisseroth and his collaborators subsequently adapted the approach for mammalian nerve cells, publishing a landmark demonstration in 2005. By introducing the genetic instructions for the light-sensitive protein into neurons, they could trigger electrical signals with precisely timed pulses of light.

The combination of genetic targeting and optical stimulation offered greater precision than conventional electrical stimulation, which can activate several types of nearby cells simultaneously. Researchers could now choose which populations of neurons responded to illumination and control when those responses occurred, down to millisecond timescales.

According to Karolinska Institutet, the technique has made it possible to investigate how nerve cells shape memories, feelings and behaviour in a living brain. Its applications include experiments examining the circuits involved in movement, sleep, fear and motivation, alongside research into neurological and psychiatric disorders.

Animal studies are using these tools to explore conditions including epilepsy, Parkinson’s disease, Alzheimer’s disease, schizophrenia and addiction. The findings can help identify which cells and circuits warrant closer investigation in humans, although understanding a disease mechanism does not automatically produce an effective treatment.

One experimental medical application involves attempts to restore some sight in people with retinitis pigmentosa, a progressive retinal disease. A study published in Nature Medicine in 2021 reported partial recovery of visual function in a blind patient after researchers combined gene delivery to the retina with specially engineered light-stimulating goggles.

The patient could locate, touch and count objects during tests, but only while using the goggles, according to the research team. The result demonstrated a possible therapeutic route, while also showing the distinction between recovering limited visual function and restoring normal sight.

Clinical applications remain less established than optogenetics’ use as a research tool, with further work needed to turn experimental findings into dependable treatments. The Nobel recognition nevertheless highlights how a basic investigation into an alga’s response to light supplied a method now used to examine some of the brain’s most difficult questions.

When will the other Nobel prizes be announced?

The remaining announcements will take place between October 6 and October 12, according to the official Nobel schedule. The times below are in Indian Standard Time (IST), converted from Central European Summer Time (CEST); except for the peace prize, they represent the earliest scheduled announcement times.

The announcements will be broadcast live through the Nobel prize’s official digital channels. The economics award’s formal name is the Sveriges Riksbank prize in economic sciences in memory of Alfred Nobel.