Santiago Ramón y Cajal

Born in Petilla de Aragón, Spain, in 1852, Santiago Ramón y Cajal trained as a physician and went on to become one of the founding figures of modern neuroscience. Working as a histologist and professor, he used improved staining methods and extraordinarily patient observation to study the microscopic structure of the brain and nervous system.

His most important achievement was showing that the nervous system is made up of separate cells rather than one continuous network, an idea that became known as the neuron doctrine. That work transformed the understanding of how the brain is organized, and it earned him the 1906 Nobel Prize in Physiology or Medicine, shared with Camillo Golgi.

Ramón y Cajal was also a gifted illustrator and writer, and his scientific drawings are famous for their clarity as well as their beauty. He died in Madrid in 1934, but his work still shapes the way scientists think about neurons, brain circuits, and the structure of the nervous system.