The Nobel prize in physiology or medicine 2026 has been awarded to three scientists for their work investigating the mysteries of the brain.
Karl Deisseroth of the Howard Hughes Medical Institute and Stanford University, Peter Hegemann of the Humboldt University of Berlin and Georg Nagel of the University of Würzburg have been awarded the prize “for their discoveries concerning light-gated ion channels and optogenetics”.
The Nobel assembly at the Karolinska Institute in Stockholm, Sweden, announced the winners on Monday. They will each receive an equal share of a prize of 12m Swedish kronor (about £900,000).
The 2026 award is the 117th time the prize has been given. Of the 235 laureates – including the latest winners – only 14 have been women and none have been awarded to black scientists.
In a nutshell the trio’s research led to the development of a light-sensitive switch that can be used to control nerve cells in the living brain, switching them on or off.
Jonathan Levin, the president of Stanford University, said the subsequent discoveries by Deisseroth, along with those of his fellow laureates, have deepened understanding of neural circuits and how they shape feelings, behaviour, and more.
“Their implications are profound, not only for understanding the human brain, but for opening possibilities into new treatments for neurological and psychiatric disorders,” he said.
The work had its origins in research by Hegemann, who wanted to explore how a green alga called Chlamydomonas swam towards light. “He discovered that its eye spot contains a light-sensitive protein that converts light almost instantly into an electrical signal, allowing the alga to move,” said Abdel El Manira, a professor of neuroscience at the Karolinska Institute and member of the Nobel assembly.
Nagel and Hegemann identified the proteins, called channelrhodopsins, and working with frog egg cells they revealed that when the proteins were exposed to blue light, they allowed charged particles – or ions – to flow into the cell, producing an electrical impulse.
Further work by the pair revealed that when the genetic instructions for one of the proteins were inserted into human or mouse kidney cells, those cells became light sensitive.
Deisseroth took the discovery even further, using rats to demonstrate that by introducing the gene for a channelrhodopsin into nerve cells, it was possible to produce electrical signals in them using light.
He and his colleagues later applied the approach to nerve cells in the motor cortex of the brains of mice, allowing them to use light – delivered by tiny optic fibres passed through their skull – to trigger movement in the rodent’s whiskers.
Subsequent work in mice showed the approach could also be used to investigate which networks of nerve cells were involved in the formation of particular memories, including fear.
While rooted in basic science, the team’s work has already had real-world implications, opening up a field of medicine known as optogenetic therapy.
In one trial it was used to partially restore the sight of a man who went blind as a result of retinitis pigmentosa, a condition that results in damage to light-sensitive cells in the retina.
In that case, the genetic instructions for making a channelrhodopsin were delivered by means of a harmless virus into retinal ganglion cells in the man’s eyes.
He was then kitted out with light-stimulating goggles that captured pictures of the world around him and converted them into single-wavelength images that were projected on to his retina using pulses of light.
Prof Botond Roska, the director of the Institute of Molecular and Clinical Ophthalmology Basel who co-led the study, welcomed the announcement of the Nobel laureates.
“This is truly wonderful news. I hope this helps to boost all efforts on optogenetic vision restoration to bring back vision to blind patients,” he said.
Anna Wedell, a professor at Karolinska Institute and a member of the Nobel committee for physiology or medicine, said the laureates’ work had provided new possibilities to map which cells were responsible for which functions, and which cells communicated with each other, opening up a new understanding of the function of the brain.
“We’ve had anatomical maps and correlations, but now we have a tool that can provide cause-and-effect relationships so we can get a functional map of the brain, exactly pinpoint which cells do what, which cells are responsible for creating behaviours or even emotions and memories in the brain,” she said.
Wedell said that by studying animals to understand how a normal, healthy brain worked, it was then possible to explore what happened when thing went wrong – for example in the case of diseases such as dementia, epilepsy and addiction.
“By understanding which cells are active in these diseases in the mouse, we can also understand where to look in the human,” she said.
