Level 1 — Absolute Beginner
Three scientists won a Nobel Prize on Monday. It is a very big prize for science.
They found a way to use light to turn brain cells on and off. The brain cells are called neurons.
The scientists are Karl Deisseroth, Peter Hegemann and Georg Nagel. Their idea helps people learn how the brain works.
- prize
- A reward for doing something great.
- scientist
- A person who studies how the world works.
- light
- What lets us see; it comes from the sun or a lamp.
- brain
- The part of the body that thinks.
- cell
- A tiny living part of the body.
- neuron
- A brain cell that sends messages.
- switch
- To turn something on or off.
- idea
- A new thought or plan.
Level 2 — Elementary
The 2026 Nobel Prize in Physiology or Medicine went to three scientists on Monday. They are Karl Deisseroth from the United States and Peter Hegemann and Georg Nagel from Germany.
They were honored for their work on light-gated ion channels and a method called optogenetics. With it, researchers can switch chosen nerve cells on or off using light.
The method started with a light-sensing protein found in a tiny pond alga. Scientists later learned to place that protein in brain cells, so a flash of light could control them.
Today labs around the world use optogenetics to study memories, emotions and behavior. The winners share a prize of 12 million Swedish crowns, about 1.2 million dollars.
- ion channel
- A tiny gate in a cell that lets charged particles pass.
- method
- A way of doing something.
- optogenetics
- A technique that uses light to control cells.
- protein
- A natural substance made by living cells.
- alga
- A simple plant-like living thing that grows in water.
- memory
- The ability to remember things.
- emotion
- A feeling such as joy or fear.
- share
- To divide something between people.
Level 3 — Intermediate
The Nobel Assembly at Sweden's Karolinska Institute awarded the 2026 Nobel Prize in Physiology or Medicine on Monday to Karl Deisseroth, Peter Hegemann and Georg Nagel for their discoveries concerning light-gated ion channels and the technique known as optogenetics.
Optogenetics allows researchers to switch the activity of selected nerve cells on or off with light. The foundation was laid by studies of proteins from single-celled algae, which respond to light by letting charged particles flow across a membrane. Once those proteins were introduced into neurons, a pulse of light could make a cell fire or fall silent on demand.
The power of the approach lies in its precision. Earlier tools, such as drugs and electrodes, tended to affect many cells at once, whereas light can be aimed at specific cell types, making it possible to ask which circuits are responsible for particular memories, emotions and behaviours.
The committee said the method is now used in laboratories around the world to reveal the brain's mysteries. Deisseroth is 54 and American, Hegemann is 71 and Nagel is 73, both German, and the three will divide a prize worth 12 million Swedish crowns, around 1.2 million dollars.
- light-gated
- Opening or closing in response to light.
- technique
- A specific method for doing a task.
- membrane
- A thin barrier around a cell.
- on demand
- Whenever it is wanted.
- precision
- Exactness and accuracy.
- electrode
- A conductor used to send or measure electricity.
- circuit
- A connected pathway of cells or parts.
- laureate
- A person honored with a major prize.
Level 4 — Advanced
The Nobel Assembly at the Karolinska Institute on Monday conferred the 2026 Prize in Physiology or Medicine on Karl Deisseroth, Peter Hegemann and Georg Nagel for discoveries concerning light-gated ion channels and the technology of optogenetics, a tool that has transformed how neuroscientists interrogate the living brain.
The story begins not in a hospital but in a pond. Microbial algae possess proteins that convert light into an electrical signal, letting ions stream across the cell membrane. Once such proteins could be expressed in mammalian neurons, researchers gained something they had long coveted: a means of making individual cells fire or fall silent with a flash of light, at millisecond timescales and with remarkable specificity.
That control has changed the questions science can pose. Rather than inferring a circuit's role from lesions or from drugs that wash across entire regions, investigators can now switch a defined population of cells on or off and observe the consequences for memory, emotion and behaviour, converting correlation into something closer to causation.
The committee observed that the method is used in laboratories worldwide to reveal the brain's mysteries. Deisseroth, 54, is American, while Hegemann, 71, and Nagel, 73, are German; they will divide the award of 12 million Swedish crowns, roughly 1.2 million dollars.
- confer
- To formally grant an award or title.
- interrogate
- To examine closely by asking probing questions.
- microbial
- Relating to microscopic organisms.
- coveted
- Strongly desired.
- specificity
- The quality of affecting only the intended target.
- lesion
- A region of damaged tissue.
- causation
- A direct cause and effect relationship.
- correlation
- A statistical link between two things.