Twitches versus movements: a story of motor cortex.

Modern study of the neurophysiology of the cerebral cortex began with Fritsch and Hitzig's discovery that electrical stimulation of the cortex produces movements. The importance of this discovery was threefold: it was the first demonstration of cortex devoted to motor function, the first indication that the cortex was electrically excitable, and the first evidence of a topographically organized representation in the brain. Fritsch and Hitzig's basic findings were soon replicated by Ferrier, but there were differences between the two studies in both method and interpretation. These different approaches have continued to reverberate in research on the function of motor cortex from the late 19th century to the present day.