Why did they win the Nobel Prize in Medicine?

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Imagine that you are in front of a huge city, containing billions of lamps and wires, and you want to know which circuit is responsible for fear, which creates memories, and which moves the hand. This city is the brain.

For many years, scientists have monitored its lights, but observing a lamp that turns on during fear does not prove that it creates fear. Here came the “optogenetic” revolution, for which the Nobel Prize in Medicine was awarded on October 5, 2026, to Peter Hegemann, Georg Nagel, and Karl Deisseroth. The name sounds difficult, but the idea is simple: we make specific neurons respond to light, and then we use flashes of light to control their activity. It is as if scientists installed a switch inside the cell that can be operated from the outside. The word “genetic” means using genetic instructions that cause the cell to make a protein that is sensitive to light, and the word “optics” refers to the light that turns on this protein.

The process is not to shine a flashlight on the head; It is a technology that requires preparing the target cells and delivering light to them, and the story begins with a humble organism, a single-celled algae, swimming towards the light. Hegemann asked: How does this organism sense and respond to light? In collaboration with Nagel, they discovered a protein that acts as a gate in the cell membrane. When light falls on it, the gate opens and ions, that is, electrically charged particles, pass through. Deisseroth and his team realized that transferring the genetic instructions for this protein to neurons could make the light fire their signals. The basic experiment was published in 2005. Why was this such a huge leap? Because nerve cells communicate with rapid electrical signals, this technology allows intervention with time accuracy measured in thousandths of a second, while targeting specific types of cells.

As other tools were developed, it became possible to activate or inactivate cells. Imagine an orchestra: Instead of hearing all the music and trying to guess the role of the violin, you can silence the violin for a moment, or play it alone, and understand its contribution to the melody. Thus, the researchers moved on from the question: “What cells are active during this behavior?” To a stronger question: “What happens if we change the activity of these cells?” This is the difference between observing the association and testing the cause. Technology has become a means of studying the circuits of memory, feelings, and behavior, and understanding the contribution of specific cells to brain functions and disorders. Its value is that it gives scientists an experiment that can be controlled, and a result that can be tested and repeated. As for treatment, there are encouraging steps, especially in the case of vision loss.

In 2021, a study documented the partial restoration of some visual functions in a patient with retinitis pigmentosa, after making remaining cells in his retina sensitive to light, with the use of special glasses. But it is a limited recovery, not a complete return of vision, and it does not mean that brain diseases are immediately treatable with this technique.

Scientists deserved the Nobel Prize because they gave us a tool that changes the way we ask about the brain, and brings us closer to understanding it experimentally. There is a further lesson in the story. The research that begins with curiosity about an algae may open a window on a person. No one knows in advance where the journey of questioning ends. Therefore, protecting basic research is an investment in possibilities that we do not see today, and that may change people’s lives tomorrow.

Quoted from “Al-Masry Al-Youm”