Scientists explained how nerves fire using a giant squid's nerve fiber

In 1952, Alan Hodgkin and Andrew Huxley threaded electrodes into the unusually thick nerve fiber of a squid — the only cell large enough to study directly at the time — and measured how sodium and potassium ions flow to create a nerve impulse. Their equations describing the action potential still underpin neuroscience, and won them a Nobel Prize in 1963.

— Alan L. Hodgkin and Andrew F. Huxley, A Quantitative Description of Membrane Current and Its Application to Conduction and Excitation in Nerve — The Journal of Physiology, 1952