David Ferrier.

We can truthfully say that somotopy (from the Greek soma=body, and topos=site) led the way to one of the most important findings of the history of neuroscience :

Cerebral localization of function was demonstrable.

David Ferrier was born and educated in Aberdeen, Scotland where he studied under Alexander Bain. At Bain's urging, he journeyed to Heidelberg in 1864 to study psychology. During that period, Heidelberg was home to both Helmholtz and Wundt. Indeed Wundt had only recently (1862) completed the Beiträge zur Theorie der Sinneswahrnehmung that contains the first programmatic statement of his physiological psychology and Ferrier must certainly have encountered Wundt's views. (from serendip.brynmawr.edu/Mind/Adaptation.html )

The electrical stimulation in anesthetized or semi-anesthetized animals became an extremely useful means to carry out mapping studies on the surface of the cortex.

The giant of this research line was to be the British physiologist and physician David Ferrier (1843-1924), who carried out a number of advanced and systematic experiments, around 1875. He stimulated with a higher precision the cortex of dogs and monkeys. In the later, he was able to draw a map with 29 different functions across the cortex, which he identified and numbered. In this way, Ferrier created the basic methodology to be used for the next three quarters of century.

Ferrier most audaciously transposed his results with monkeys to the human brain, by producing an analogous map of functional localization.

This was experimentally unsubstantiated until the first decades of the next century, but it was very important to launch a new era in the medical applications of cerebral localization studies, especially for neurosurgery. Neurologists and neurosurgeons could now predict the localization of a tumor or lesion on the brain, on the basis of its consequences on the neurologial examination of motor and sensory functions.

Ferrier was inspired in this pioneering endeavour by his teacher and friend the great forefather of British neurology, John Hughlings Jackson (1835–1911). He was the preponent of the so-called doctrine of hierarchical organization of brain functions, which became the basis of clinical neurological practices afterwards. By studying brain lesions which were associated to motor epileptical manifestations, Jackson was able to discover several functional areas of the brain, and Ferrier had the strongest desire to prove that Jackson was right, and that this knowledge would be useful for practical purposes.

Ferrier was also a pioneer in the combined use of lesion and stimulation techniques in the same areas of the brain, with the aim of testing consistent hypothesis about the proposed maps. He lesioned the areas in dog and monkey brains which, upon stimulation, produced some movements. Consistency of mapping could be achieved when the same voluntary or involuntary movements would be lost due to the lesions. In dozens of classical experiments, Ferrier was able to prove this assertion several times, convincing him on the reality of an utmost one-to-one mapping of function in the brain. He was opposed by many neuroscientists, who were still reluctant to believe that such preciseness of localization was real. Many defended the idea that the cortex was equipotential in function and had no specialization.

Ferrier was involved in a famous scientific dispute with German neurophysiologist and neurologist Friedrich Goltz (1834-1902), who could not observe focal disruption of motor and behavioral functions in dogs, despite extensive cortical lesions. Ferrier was able to demonstrate inadequacies and experimental errors in Goltz's experiments and publicly won the dispute.