While dissecting frogs in the 1780s, Italian physician Luigi Galvani noticed something extraordinary. A dead frog’s leg suddenly twitched when a metal instrument touched an exposed nerve. The animal was no longer alive, yet its muscles contracted as if they had received a command from the brain.
At the time, no one understood how the brain communicated with the body. Many scientists believed nerves carried invisible fluids or “animal spirits.” Galvani wondered whether the twitching revealed something entirely different: that the nervous system generated its own form of electricity. He called it animal electricity.
Galvani’s interpretation would later be debated, but his experiments transformed science. They shifted the study of the nervous system from speculation toward measurable electrical phenomena and inspired a generation of researchers to investigate how nerves and muscles function.
Today we know that neurons communicate through tiny electrical signals created by the movement of charged ions across their membranes. Every major neurotechnology—from EEG and deep brain stimulation to transcranial magnetic stimulation and brain-computer interfaces—rests on the same fundamental insight that Galvani’s twitching frog helped uncover: the nervous system is electrical.
Last Updated on October 6, 2026 | Published: July 1, 2026