Carpenter ranked Ferrier’s cerebral localisation among the greatest advances in the physiology of the nervous system made in the past 50 years.¹ It formed a direct link between Jackson and Sherrington, with both of whom he had worked.

Born in Aberdeen, Ferrier studied there under Alexander Bain, on whose advice in 1864 he visited Heidelberg, to study psychology with Helmholtz and Wundt. Wundt had just (1862) completed the Beiträge zur theorie der sinneswahrnehmung that contained the first statement of his “physiological psychology”. Ferrier completed his medical training at Edinburgh where Thomas Laycock,^2–3 inclined him towards neurology.

He worked in London from 1880, and was appointed Professor of Neuropathology, King’s College Hospital, in 1889. But his major research began earlier at The West Riding Lunatic Asylum, Wakefield. There he showed that stimulation of the cerebral cortex could produce movements and fits, and that cerebral functions were localised in definable discrete areas.

Before him, in 1866, Friedrich Albert Lange (1828–75) had distinguished between localisation of function and localisation of symptoms. Broca, Bouillaud,⁴ Flourens,⁵ and others had tried to relate behaviour, language, and disease to different areas of the brain, but Franz Joseph Gall’s (1758–1828) phrenology was still accepted by many.⁶ Influenced by Bain and Spencer, Ferrier^7–8 tested Hughlings Jackson’s notion that motor and sensory functions must be represented in an organised fashion in the cortex. Gustav Theodor Fritsch and Eduard Hitzig in 1870, using galvanic stimulation of the cerebrum in the dog⁹, had recently shown that circumscribed cortical areas control movements of the contralateral limbs and that ablation of these areas caused weakness in these limbs. Their findings established electrophysiology as an experimental tool and showed the localisation of motor function in the hemispheres.

Ferrier used faradic rather than galvanic current to elicit movements that resembled primate walking, grasping, scratching, and thereby confirmed and extended the results of Fritsch and Hitzig. Ferrier localised smell in the uncus of the temporal lobe; hearing in the superior temporosphenoidal convolution; and primate vision in the angular gyrus, although this was later corrected by Munk’s discovery of the occipital visual cortex. Ferrier used both ablation and electrical stimulation to produce topography of localisation of function in several species.

Removal of the precentral gyrus, he found, caused paralysis and a hemiplegic position of the contralateral limbs. In 1876 he collected his results to produce his acclaimed The functions of the brain.¹⁰ This demonstrated that ablations and faradic stimulation of the brain were better than the galvanic techniques of Fritsch and Hitzig. He had thereby mapped sensory and motor areas across several species, thus expanding both understanding¹¹ and localisation of motor and sensory functions.^12–14

Ferrier also performed decerebration experiments to distinguish between voluntary and reflex movement, and examined the control of eye movements by electrical stimulation of the cerebellum. He was not obsessed by the anatomical localisation. The functions of the cerebrum were sensorimotor:

“From the complexity of mental phenomena and the participation in them of both motor and sensory substrata, any system of localization of mental faculties which does not take both factors into account must be radically false.” He thus anticipated 20th century holistic concepts of cerebral function.

“Ferrier was more than an experimenter; he was, rather, a philosopher who did not philosophise but who experimented,” remarks Rioch.¹⁵

By making lesions in the anterior frontal cortex, he deduced the effect on function:

“while not actually deprived of intelligence . . .they had lost the faculty of attentive and intelligent observation.”

Thus, the frontal lobes might subserve the function of selection and inhibition of competing ideas.

He dedicated his work to Jackson:

“To Dr Hughlings Jackson who from a clinical and pathological standpoint anticipated many of the more important results of recent experimental investigation into the functions of the cerebral hemispheres, this work is dedicated as a mark of the author’s esteem and admiration.” Ferrier The functions of the brain (1876).

Jackson, similarly, had been inspired by Spencer and frequently cited his writings. Sherrington, in turn, dedicated his lectures on The integrative action of the nervous system (1906) to Ferrier. And in his obituary notice of Ferrier for the Royal Society,¹⁶ Sherrington remarked:

“Ferrier has done the most important research in proving cerebral localization, in placing it at the centre of neurological interest, and in providing the basis for a “scientific phrenology””.¹¹

He continued his clinical work applying these experimental findings to patients, and encouraging surgeons to operate on intracranial lesions; thus, Rickman Godlee said he was a powerful force in initiating brain surgery.

Among many honours, he received an Hon DSc, University of Cambridge, in 1914 and in 1911 a Knighthood. He was elected FRS in 1876, FRCP in 1877, and Goulstonian Lecturer in 1878. Not least of this great pioneer’s achievements was the foundation of the journal Brain, with Hughlings Jackson, Sir John Bucknill, and Sir James Crichton-Browne.