Ferrier was born in Woodside, Aberdeen, and educated at Aberdeen Grammar School before studying for an MA at Aberdeen University (graduated 1863). As a medical student, he began to work as a scientific assistant to the influential free-thinking philosopher and psychologist Alexander Bain (1818–1903), one of the founders of associative psychology. Around 1860, psychology was finding its scientific foundation mainly in Germany, with the rigorous research of Hermann von Helmholtz (1821–1894), who had trained as a physicist, and of Wilhelm Wundt (1832–1920). They focused their work mainly in the area of sensory psychophysiology, because it was the most rewarding for the approach based on the paradigms of experimental physics. Both worked at the University of Heidelberg. In 1864 Bain prompted Ferrier to spend some time in their laboratories.
On returning to Scotland, Ferrier graduated in medicine in 1868 at the University of Edinburgh. A few years later, in 1870, he moved into London and started work as a neuropathologist at the King's College Hospital and at the National Hospital for Paralysis and Epilepsy, Queen Square. The latter – now the National Hospital for Neurology and Neurosurgery – was the first hospital in England to be dedicated to the treatment of neurological diseases and has a David Ferrier ward named in his memory.
At that period, the great neurologist John Hughlings Jackson (1835–1911) worked in the same hospital as Ferrier. Jackson was refining his concepts of the sensorimotor functions of the nervous system, derived from clinical experience. Jackson proposed that there was an anatomical and physiological substrate for the localization of brain functions, which was hierarchically organized.
Influenced by Jackson who became a close friend and mentor, Ferrier decided to embark on an experimental program. It aimed to extend the results of two German physiologists, Eduard Hitzig (1838–1907) and Gustav Fritsch (1837–1927). In 1870, they had published results on localized electrical stimulation of the motor cortex in dogs. Ferrier wanted also to test Jackson's idea that epilepsy had a cortical origin, as it was suggested by his clinical observations.
Coincidently, Ferrier had received a proposal to direct the laboratory of experimental neurology at the West Riding Lunatic Asylum, a psychiatric hospital located in Yorkshire. The hospital's director was the psychiatrist James Crichton-Browne (1840–1938). Working under good material conditions and having an abundance of animals for experimentation (mainly rabbits, guinea pigs and dogs), Ferrier started his experiments in 1873, examining experimental lesions and electrical stimulation of the cerebral cortex. Upon his return to London, the Royal Society sponsored the extension of his stimulation experiments to macaque monkeys, work he undertook at the Brown Institution in Lambeth. By the end of the year, he had reported his first results to local and national meetings and had published an account in the enormously influential West Riding Lunatic Asylum Medical Reports.
Ferrier had succeeded in demonstrating, in a spectacular manner, that the low intensity faradic stimulation of the cortex in both animal species indicated a rather precise and specific map for motor functions. The same areas, upon being lesioned, caused the loss of the functions which were elicited by stimulation. Ferrier was also able to demonstrate that the high-intensity stimulation of motor cortical areas caused repetitive movements in the neck, face and members which were highly evocative of epileptic fits seen by neurologists in human beings and animals, which probably were due to a spread of the focus of stimulation, an interpretation very much in line with Jacksonanian thought.
These – and other investigations in the same line – resulted in international fame for Ferrier and assured his permanent place as one of the greatest experimental neurologists. In June 1876 he was elected a Fellow of the Royal Society at the age of 33  and Fellow of the Royal College of Physicians the following year. He was also the first physiologist to make an audacious (if scientifically incorrect) transposition of cortical maps obtained in monkeys to the human brain. This proposal soon led to practical consequences in neurology and neurosurgery. A Scottish surgeon, Sir William Macewen (1848–1924), and two British physicians, the clinical neurologist, Hughes Bennett, and Rickman J. Godlee demonstrated in 1884, that it was possible to use a precise clinical examination to determine the possible site of a tumor or lesion in the brain, by observing its effects on the side and extension of alterations in motor and sensory functions. This method of functional neurological mapping is still used today. Jackson and Ferrier were present at the first operation performed by Godlee on 25 November 1884. Godlee was a nephew of the eminent physician Sir Joseph Lister (1827–1912), the discoverer of surgical antisepsis.
Practical results of animal research were used to justify Ferrier before a noisy public persecution carried out by antivivisectionist societies against him and other scientists, who were accused of inhumane use of animals for experimental medicine. In 1892, Ferrier was one of the founding members of the National Society for the Employment of Epileptics (now the National Society for Epilepsy), along with Sir William Gowers and John Hughlings Jackson.
He died in 1928, of pneumonia, in London. He left behind a widow, Constance (née Constance Waterlow, the sister of the painter Ernest Albert Waterlow), and a son and daughter; his son Claude was a well-known architect.
Of Ferrier's publications, two books are notable. The first one, published in 1876, The Functions of the Brain, describes his experimental results and became very influential in the succeeding years, in such a way that today it is considered one of the classics of neuroscience. In 1886 he published a new edition, considerably expanded and reviewed. The second book, which was published two years later – The Localization of Brain Disease – had as its subject the clinical applications of cortical localization. Together with his friends Hughlings Jackson and Crichton-Browne, Ferrier was one of the founders of the journal Brain in 1878, which was dedicated to the interaction between experimental and clinical neurology and is still published today. In that year Ferrier delivered the Goulstonian Lecture to the Royal College of Physicians on "The localisation of cerebral diseases".
- "Lists of Royal Society Fellows 1660–2007". London: The Royal Society. Retrieved 16 July 2010.
- Wozniak, RH: David Ferrier. The Functions of the Brain (1876). In: Classics in Psychology. Thoemmes.
- Young, R.M.: David Ferrier: Localization of Sensory Motor Psychophysiology. In: Mind, Brain and Adaptation in the Nineteenth Century: Cerebral Localization and Its Biological Context from Gall to Ferrier
- Wozniak, R.H.: Hughlings Jackson: Evolution and Dissolution of the Nervous System (1881–7; Collected 1932). In: Classics in Psychology, 1855–1914: Historical Essays, Thoemmes.
- 100 Years of Brain.
- Macewen, Sir William (1848–1924), professor of surgery, University of Glasgow