Hodgkin–Huxley equation

Sound enters the ear and hits a thin membrane inside the cochlea, the spiral organ in the inner ear. This membrane doesn't just vibrate like a string; it actively pushes the vibrations when they are weak and stops when they are strong. That's how the ear hears both a whisper and a loud conversation. Scientists built a model where each piece of the membrane is a tiny pendulum with a spring.

A bell hidden in a thick box can be made to ring without opening the lid. Just send a sound wave through the walls, and the clapper will tremble. That's roughly how transcranial ultrasound works: sound passes through the skull bones and makes neurons deep in the brain 'ring'—generating electrical impulses.

A neuron transmitting a signal is like a tiny battery that quickly discharges and recharges. For nearly 70 years, it was believed that a special "potassium valve," opening with a delay, was responsible for the recharge phase. New work claims this current is a ghost.

A neuron transmitting a signal is like a tiny battery that quickly discharges and recharges. For nearly 70 years, it was believed that a special "potassium valve," opening with a delay, was responsible for the recharge phase. New work claims this current is a ghost.

A stadium packed with fans hears the announcer’s voice for the first time, and instantly the whole place erupts. The message sounds again and again. Only a handful of people in nearby rows respond. That’s roughly how neural networks behave in brain organoids — tiny lab-grown replicas of the brain.

Inside each of us, invisible clocks are ticking. They control the release of cortisol — the hormone that helps us wake up in the morning, cope with anxiety, and keep our immune system on its toes. In adrenal insufficiency, these clocks break down: the body can't produce the right amount of cortisol on its own.

A neuron is like a complex musical instrument. To understand how it responds to a touch, you used to have to connect to each string directly — a delicate, slow procedure that only works for individual cells.

A neuron resembles an electrical circuit with batteries and variable resistors. The resistors are played by ion channels — protein pores in the membrane that open and close, letting charged particles through. Whether a nerve impulse fires depends on how fast and at what voltage these pores operate.

A neuron perceives electrical signals like an ultrasensitive microphone picking up the faintest vibrations.

A membrane for water electrolysis is like a sponge soaked with water. Inside it, hydroxide ions, particles that carry electric charge, must move freely. But exactly how they move has long been a mystery: tracking each ion in an experiment is too difficult.

An ion channel in a cell membrane is a gate just a few atoms wide. Every second, millions of charged particles, sodium and potassium ions, pass through it. Classical physics said that to get through, an ion must jump over an energy barrier, like a traveler crossing a high mountain pass.

A mouse brain contains about 70 million neurons, and the connections between them are far from evenly distributed: some cells have only a couple of dozen contacts, while others have thousands. It's like a city with quiet alleys and bustling squares. But until now, it was unclear how this unevenness affects the brain's actual function.

Hydrogen is the lightest fuel, and its conversion into electricity on a metal surface resembles a game of ping-pong: hydrogen atoms alternately attach to and detach from the electrode. But the score in this game depends on solution acidity in ways that were unexpected. Classical formulas predict a smooth change, while experiments show jumps and kinks.

The visible edge of the universe is a holographic screen that, like a black hole, obeys laws discovered by Bekenstein and Hawking. Normally, information is preserved on it, but calculations show that if a few bits are lost, energy is released that accelerates expansion.

A light pulse in an optical fiber is like a starter's pistol shot: short, sharp, and unmistakable against the silence. It is exactly such pulses that the new artificial neuron, built on a silicon chip, produces.