The History of Neuroscience 5: Discovery of the Neuron and Its Connections

Abstract

Thanks to the invention of the microscope equipped with an achromatic lens, research on the histology of the nervous system flourished during the 19th century. Jan Evangelista Purkinje, together with Gabriel Valentin, first depicted individual nerve cells. Robert Remak, one of the most remarkable microscopists of the 19th century, made the pivotal discovery that the cell body (globule) and fibers arising from the globule formed a single unit. In addition to improvements in microscopes, a new method of visualizing nervous tissue was developed—namely, the silver staining method introduced by Camillo Golgi. Golgi could identify the types and delicate branches of axons. However, he believed that axons always directly merged with other axons, which was the basis of the reticular or nerve net theory. Santiago Ramón y Cajal, the founder of modern neuroscience, finally established the cornerstone of the neuron doctrine, according to which the nerve cell is the basic unit of the nervous system and information flows from unit to unit without direct fusion. This structure is called the synapse. Key words: Achromatic lens; Histology; Silver staining; Neuron doctrine; Synapses.