Prof. Ali Farazmand, an Associate Member of the Biology Division of the Department of Basic Sciences of the Academy, in a commentary regarding the 2026 Nobel Prize in Physiology or Medicine, has characterized optogenetics as a quintessential embodiment of the link between fundamental scientific discoveries and cutting-edge biomedical technologies, denoting it as a pivotal advancement in the comprehension of cerebral mechanisms. The text is provided below: The 2026 Nobel Prize in Physiology or Medicine was awarded in the field of optogenetics—a method used to study how neurons work to shape memories, emotions, and behaviors in brain. The laureates are Peter Hegemann and Georg Nagel, recognized for discovering a remarkable protein called channelrhodopsin in Chlamydomonas reinhardtii, a single-celled alga, and Karl Deisseroth, who utilized light to employ this protein as a switch to control neurons. A fundamental breakthrough by Peter Hegemann was the discovery of Chlamydomonas (a model organism in biological research) that enables the alga to move toward light. In the early 1990s, he discovered that the alga perceives light using its eyespot. In a sufficient light intensity, the alga swims toward the light source. Hegemann, using tiny electrodes, measured the electrical signals generated in Chlamydomonas when the eyespot was illuminated. The algae responded incredibly quickly; an electrical impulse occurred just half a millisecond after light reached the eyespot. Compared to other biological systems known to researchers at the time, this response was remarkably fast. For instance, light striking the human eye triggers a complex chemical chain reaction involving multiple stages. The final protein in this chain—an ion channel—forms a pore in the cell surface through which charged ions can flow to generate an electrical signal. The entire process lasts at least 10 milliseconds. How, then, could the response to light in Chlamydomonas be more than twenty times faster than in our eyes? He postulated a single protein complex involved in absorbing light and functioning as an ion channel. However, his proposal was met with skepticism. A few years later, a team of Japanese researchers—who had identified numerous genes in the organism by sequencing its genome—enabled Hegemann’s group to discover two genes that bore striking similarities to known light-sensing protein genes. Ultimately, in 2000, his team and Georg Nagel precisely identified this protein. Embedded in the algal membrane, the protein possessed unique properties: upon exposure to light, it opened an internal channel allowing charged ions to flow into the cell, thereby generating an electrical impulse. They discovered that, regardless of the host cell type, the cells became light-sensitive, as the protein worked in accordance if frog eggs. The third Nobel laureate, Karl Deisseroth, introduced the gene encoding this protein into rodent neurons and succeeded in triggering a neural signal by shining blue light on the cells. He published this major technical breakthrough in 2005. Two years later, he and his colleagues succeeded in utilizing this light-based neuronal switch within the brains of live mice. They found that this process activated the cells and enabled them to communicate with other neurons. This technology—a form of light-controlled "switch"—is known as "optogenetics," and it revolutionized the field of neuroscience. By utilizing optogenetics, researchers have been able to identify the neural circuits responsible for specific memories, emotions, and behaviors linked to neurological and psychiatric disorders. In clinical medicine, researchers are also working to use this method to restore vision to individuals with visual impairments. Deisseroth says: "We use light to turn individual cells—or even specific cell types and connections between different brain regions—on or off. We can activate or deactivate these elements with millisecond precision and in real-time, precisely as behaviors or cognitive activities are occurring." This work enables us to discover what is truly important for brain function and to begin precisely mapping functions and functional disorders. Optogenetics is fundamentally transforming our understanding of the brain. This technology has also provided important insights into how the nervous system interacts with cells in other parts of the body, such as the heart and the gut. Insights gained from optogenetic tools have helped researchers better understand healthy brain function as well as conditions such as depression, schizophrenia, Parkinson’s, and Alzheimer’s. A highly informative aspect of the 2026 Nobel Prize is highlighting the role of basic sciences and fundamental discoveries, and the convergence of these findings with modern technologies in exciting biomedical applications. Sources: • NEWS Nature, 05 October 2026 • MLA style: Popular information. NobelPrize.org. Nobel Prize Outreach 2026. Tue. 6 Oct 2026. <https://www.nobelprize.org/prizes/medicine/2026/popular-information/>