The Nobel Prize in Physiology or Medicine for 2026 has been awarded to three scientists, Karl Deisseroth, Peter Hegemann and Georg Nagel.
Their pioneering work in optogenetics has been recognised by the Nobel Prize Committee for its potential to advance our understanding of how the brain forms memories, feelings and behaviours. The Nobel Prize was jointly awarded, sharing the 12 million Swedish kronor prize equally.
The study into optogenetics first started with Nagel, Hegemann and colleagues in 2002 and 2003, when they identified two proteins in the eyespot of green alga (channelrhodopsin-1 and channelrhodopsin-2). These proteins are light-detecting ion channels that open to allow ions in, altering the electrical current.
The 2003 research into channelrhodopsin-2 was particularly significant, as it revealed rhodopsin’s important role as a directly light-switched cation channel and eventually using this for light signal transduction, the key to optogenetics.
Light signal transduction is the process by which living organisms convert physical light energy into chemical or electrical signals, altering physiological responses.
Deisseroth’s lab at Stanford, in 2005, found that the expression of the channelrhodopsin-2 gene in neurons enabled their electrical activity to be controlled by blue light.
This breakthrough revolutionised the field of optogenetics, a technique which controls specific cells using light-sensitive proteins and ion channels. Following this discovery, optogenetics has opened the possibility of eventually targeting neural circuits involved in detrimental neurological disorders, which are currently untreatable.
Optogenetics can be an opportunity for researchers to fully understand specific disease mechanisms and, from this, design effective treatments.
But why have the scientists only been awarded for their work now?
Even though optogenetic proteins were first identified in the early 2000s, the Nobel Prize Committee has only recognised them this year. This gives time for a laboratory discovery to transition from just initial findings to a widespread, practical adoption across global research labs.
Therefore, the Karolinska Institute routinely awards prizes ten to 30 years after the core scientific breakthrough occurs. The Nobel Assembly waits to see whether a technique moves beyond a clever discovery to practical application. The most profound practical application of optogenetics to date is the successful human clinical trials in treating retinitis pigmentosa (a degenerative genetic disease causing blindness).
This study introduced genes that make surviving retinal cells sensitive to light, to bypass damaged photoreceptors and stimulate electrical signals along the visual pathway to the brain.
While vision was not fully restored, blind patients were able to locate, count and touch objects when using specialised goggles, while electroencephalogram (EEG) recordings also showed activity in the visual cortex.
This is just one example of optogenetics’ potential to restore lost function, highlighting its promise as a future therapeutic approach for severe neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
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