The modern history of epilepsy surgery did not begin in Montreal.
Decades before Wilder Penfield and Herbert Jasper developed their famous programme at the Montreal Neurological Institute, British neurologists and surgeons were already attempting something extraordinarily ambitious: using the pattern of a person’s seizures to decide where to operate on the cerebral cortex.
At the centre of that transition was Victor Horsley.
In 1886, Horsley operated on patients with focal epilepsy at the National Hospital for the Paralysed and Epileptic at Queen Square in London. These operations are widely regarded as the beginning of modern localisation-guided epilepsy surgery.
This page focuses on that nineteenth-century turning point. The site’s broader Early Epilepsy Surgery page covers the wider surgical timeline, while the Montreal procedure is treated separately.
Before epilepsy surgery, there had to be localisation
Horsley’s operations were possible only because neurologists had spent decades learning to read focal seizures as signs of cerebral localisation.
John Hughlings Jackson had shown that a seizure beginning in one hand, one side of the face or one limb could spread in an orderly sequence.
He argued that this progression reflected abnormal discharge through organised regions of the cerebral cortex.
That meant seizure semiology could potentially identify the region responsible for an attack.
The surgical implication was radical: if a focal seizure pointed to a particular cortical area, perhaps a surgeon could expose that area and remove the diseased tissue.
David Ferrier provided experimental support
David Ferrier’s animal stimulation experiments in the 1870s strengthened the localisation framework.
Electrical stimulation of different cortical regions produced different movements.
The experimental motor map did not perfectly correspond to modern cortical mapping, but it gave surgeons and neurologists a practical way to connect observed movement with cerebral anatomy.
Jackson’s bedside observations and Ferrier’s laboratory work therefore converged.
One came from watching spontaneous seizures in people. The other came from stimulating cortex experimentally.
Horsley would turn that convergence into surgery.
Who was Victor Horsley?
Victor Alexander Haden Horsley was born in 1857.
He trained in medicine and surgery and developed a strong interest in experimental neurophysiology.
In 1886, at the age of 29, he was appointed to the National Hospital at Queen Square in a surgical role devoted to diseases of the nervous system.
Historical reviews often describe him as the first surgeon appointed specifically to a hospital post to perform brain surgery.
His work extended far beyond epilepsy. He operated on tumours, spinal disease, trigeminal neuralgia, pituitary disorders and traumatic lesions, and he also contributed to experimental physiology, antisepsis and surgical technique.
But epilepsy was one of the conditions through which his surgical approach became historically transformative.
Why 1886 matters
The year 1886 is often used as the starting point for modern epilepsy surgery.
That does not mean no one had ever operated on the skull or brain before Horsley.
Cranial operations had existed for centuries, and surgeons such as William Macewen had already performed important intracranial operations.
What was new was the deliberate use of neurological localisation to guide resection of a suspected epileptogenic cortical lesion.
In other words, the seizure itself helped determine where the surgeon should go.
The patient known as James B.
One of Horsley’s most famous early epilepsy surgery patients is recorded in later historical literature as James B.
The patient had developed focal seizures after a previous depressed skull injury.
The seizure pattern was consistent with involvement of the sensorimotor cortex, and the clinical localisation corresponded with the area of old injury and cortical scarring.
On 25 May 1886, Horsley operated and removed the scarred cortical tissue.
Hughlings Jackson and David Ferrier were present.
The case has become one of the symbolic starting points of modern epilepsy surgery because diagnosis, localisation and resection were explicitly linked.
This was not surgery guided by EEG
There was no EEG.
Hans Berger’s first human EEG recordings were still nearly four decades away.
There was no MRI, CT, PET, SPECT or video-EEG.
Localisation depended on history, examination, seizure semiology, visible skull injury, neurological deficits and anatomical reasoning.
The operation therefore relied on an extraordinary degree of confidence in clinical observation.
The patient’s movements during a seizure were, in effect, part of the map.
A second case showed how bold the method had become
Another early Horsley case is often identified as Thomas W.
Unlike the post-traumatic case, localisation was not based on an obvious skull defect.
Jackson had observed a seizure pattern that resembled movements produced in Ferrier’s experimental cortical stimulation work and inferred a likely cortical hand area.
Horsley operated on the basis of that localisation.
A tuberculoma was found and removed.
The historical importance of the case lies in what it demonstrated: seizure semiology alone could sometimes point surgeons toward an unsuspected structural lesion.
The first operations were largely lesional
Early epilepsy surgery was not the same as modern non-lesional epilepsy surgery.
Horsley and his contemporaries generally operated when they believed there was a visible or probable structural lesion — for example, traumatic scar tissue, tumour or another cortical abnormality.
The aim was usually to remove the pathological tissue believed to be provoking seizures.
They were not yet performing the kind of extensive electrophysiological mapping used later to define an epileptogenic zone in tissue that looked structurally normal.
Why traumatic epilepsy mattered
Post-traumatic epilepsy offered nineteenth-century surgeons a particularly attractive target.
A patient might have a visible skull injury, a known history of trauma and focal seizures beginning in a body region corresponding to the damaged cortex.
Those pieces of evidence could converge even without imaging.
That made traumatic cortical scars among the earliest plausible candidates for surgical treatment.
Historical reviews of the period therefore describe the earliest epilepsy operations as being dominated by traumatic lesions and superficial tumours.
Horsley also used electrical stimulation
Horsley is important not only because he removed cortical tissue.
Historical research indicates that he was among the earliest surgeons to use electrical stimulation of the human cerebral cortex intraoperatively.
There is evidence that he used stimulation diagnostically by 1884 and in epilepsy surgery in 1886.
The purpose was to help identify functional motor cortex and relate exposed cortical regions to the patient’s clinical symptoms.
This was an early predecessor of the cortical mapping methods that would later become central to epilepsy surgery.
Why stimulation was risky and valuable
Electrical stimulation could produce movement and, in some cases, epileptiform activity.
That made it both informative and potentially hazardous.
For surgeons, the technique provided a direct way of asking whether exposed cortex corresponded to a particular body region.
For neurologists, it offered experimental confirmation that cortical organisation inferred from seizure patterns had a physical basis.
It helped close the loop between observation, experiment and surgery.
Surgery became a neurological collaboration
One of the most important features of these early operations was collaboration.
Horsley was the surgeon.
Jackson brought seizure semiology and neurological localisation.
Ferrier brought experimental cortical physiology.
The success of localisation-guided surgery depended on all three kinds of expertise.
That multidisciplinary structure foreshadowed the modern epilepsy surgery team, even though today’s teams include far more disciplines and technologies.
Queen Square became a natural centre for this work
The National Hospital for the Paralysed and Epileptic had opened in 1860.
By the 1880s it brought together a remarkable concentration of expertise in epilepsy, cortical localisation and neurological disease.
Patients with difficult seizures could be observed repeatedly by specialists who were actively developing theories of brain function.
When Horsley joined that environment, the theoretical groundwork for epilepsy surgery was already unusually advanced.
The operating theatre became the next stage of the same research programme.
Horsley changed surgical technique as well as surgical indication
Horsley was not simply applying existing general surgery to the brain.
He developed and refined techniques intended to make intracranial surgery safer.
Historical accounts credit him with innovations including the use of bone wax to control bleeding from skull edges and changes in scalp incision design.
He also performed extensive animal experiments to refine operative technique before applying procedures to patients.
These developments mattered because late nineteenth-century brain surgery was still extremely dangerous.
Antisepsis made the era possible
Localisation alone would not have created modern neurosurgery.
The growth of antiseptic and aseptic surgical practice in the nineteenth century was equally important.
Without improved control of infection, elective brain surgery carried an enormous risk of postoperative sepsis.
Advances in anaesthesia, haemostasis and surgical technique also reduced the dangers of opening the skull.
Epilepsy surgery therefore emerged from several revolutions at once: neurology, physiology, anaesthesia and antiseptic surgery.
Localisation was still imperfect
The early surgeons did not possess a precise cortical atlas equivalent to modern functional mapping.
Brain anatomy varied between individuals.
Surface landmarks did not always correspond neatly to function.
Seizure spread could mislead localisation.
A visible lesion might not represent the entire epileptogenic region.
And surgeons could not see deep temporal, insular or other intracranial networks through simple surface inspection.
These limitations placed a natural ceiling on what nineteenth-century epilepsy surgery could achieve.
The motor cortex dominated early surgical thinking
Early focal epilepsy surgery naturally concentrated on motor seizures.
Motor manifestations were visible.
Their progression could be observed in detail.
Experimental stimulation had produced a relatively practical motor map.
And lesions near the cortical surface were surgically accessible.
By contrast, seizures involving memory, emotion, visceral sensations or altered awareness were much harder to localise surgically at that time.
Removing motor cortex carried a cost
Resecting tissue involved in movement could reduce seizures but also risk weakness or paralysis.
Early surgeons therefore faced a dilemma that remains central to epilepsy surgery: the tissue causing seizures may also support important normal function.
Horsley’s operations on motor cortex contributed not only to epilepsy treatment but also to understanding how much function could be lost, retained or reorganised after cortical removal.
The balance between seizure control and neurological deficit was present from the beginning.
What counted as success?
Nineteenth-century surgical reports did not use today’s standardised seizure-outcome scales.
Follow-up could be incomplete.
Some patients improved dramatically; others had persistent seizures, neurological deficits or later recurrence.
Published success stories can therefore create a more optimistic picture than the full historical record warrants.
Modern historians treat these cases as proof of principle rather than evidence that early epilepsy surgery was routinely safe or curative.
Horsley was not the only pioneer
The history should not be reduced to one surgeon.
William Macewen in Scotland was another foundational figure in early neurosurgery.
In Germany, Fedor Krause became an important pioneer of epilepsy surgery and cortical stimulation.
Other surgeons in Europe and North America also explored localisation-guided operations as the nineteenth century ended.
Horsley occupies a central place because his 1886 work brought neurological localisation and planned cortical resection together so clearly, but the field developed internationally.
Fedor Krause extends cortical stimulation
Krause later became strongly associated with the use of electrical cortical stimulation in epilepsy surgery.
For many years he was sometimes credited as the first to use intraoperative stimulation for localising epileptic cortex.
Historical reassessment has shown that Horsley and others probably preceded him.
Krause’s importance remains substantial: he helped systematise cortical mapping and surgical treatment of focal epilepsy in Germany.
The operation was guided by seizure semiology
This is the most important historical point.
Before EEG, seizure description was not merely part of diagnosis.
It could determine an operative target.
Which finger moved first?
Which direction did the movement spread?
Did the face become involved before the arm?
Was weakness present afterwards?
These details had surgical consequences.
The nineteenth-century epilepsy history pages on Hughlings Jackson therefore lead directly into this surgical chapter.
Why Montreal came later
The Montreal programme of Wilder Penfield and Herbert Jasper in the twentieth century did something different.
It combined neurosurgery with EEG, electrocorticography, systematic cortical stimulation and detailed functional mapping.
That allowed surgeons to investigate epileptic activity even when the abnormality was not obvious from the surface.
Horsley’s era supplied the foundational principle: focal seizures can identify a surgically relevant cortical region.
Montreal would turn that principle into a much more sophisticated electrophysiological programme.
Before imaging, the skull itself could be evidence
In post-traumatic cases, surgeons sometimes relied on external anatomy as part of localisation.
A depressed fracture or scar could suggest where underlying cortical injury lay.
Modern imaging has made that kind of inference seem primitive, but it was rational within the available evidence.
The combination of known trauma, focal seizures and a matching skull lesion could provide a surprisingly coherent localisation hypothesis.
When there was no visible lesion
The greater challenge came when seizure semiology suggested a region but no external lesion was visible.
Cases such as Horsley’s operation on Thomas W. showed that surgeons were willing to trust neurological localisation enough to explore apparently intact skull and cortex.
Finding a removable lesion in such a patient strengthened confidence in the localisation method.
It also encouraged the idea that epilepsy surgery might eventually be possible even when the pathology was not obvious before operation.
Why the 1886 operations were conceptually different from trepanation
Trepanation involved opening the skull, sometimes for medical reasons and sometimes for reasons that cannot now be reconstructed confidently.
Horsley’s operations were fundamentally different.
They were based on a neurological theory of cortical function.
The surgeon attempted to identify a specific pathological region and remove it because it was believed to generate focal seizures.
This is why historians usually distinguish nineteenth-century localisation-guided brain surgery from much earlier cranial operations.
Epilepsy surgery becomes a test of localisation theory
Every operation was also an experiment in neurological reasoning.
If the patient’s seizure semiology predicted one cortical region, the surgeon found pathology there, and seizures improved after removal, the result supported the localisation theory.
Surgery therefore fed information back into neurology.
The operating theatre became a place where hypotheses about brain organisation could be tested against anatomy and outcome.
The cost of learning from patients
This history also requires ethical perspective.
Nineteenth-century standards of consent, risk disclosure and research ethics were not those of modern medicine.
Patients underwent procedures at a time when neurological deficits, infection, haemorrhage and death were significant possibilities.
The scientific value of these operations should not obscure the fact that knowledge was gained through real human risk.
Modern epilepsy surgery developed partly because those risks were progressively reduced by later generations.
Horsley’s wider legacy
Horsley later collaborated with Robert Clarke on an experimental stereotactic apparatus for animal research.
The Horsley–Clarke frame would become historically important in the development of stereotactic neuroscience.
That later work did not directly create modern SEEG, but it reflects the same ambition that characterised Horsley’s epilepsy surgery: to connect precise anatomy with controlled intervention.
What Horsley could not yet do
He could not record interictal spikes from scalp EEG.
He could not monitor seizures continuously.
He could not obtain MRI-defined structural lesions.
He could not perform stereoelectroencephalography.
He could not map language and memory with modern neuropsychological methods.
He could not define a distributed epileptogenic network.
His surgery was therefore necessarily restricted to cases in which clinical and structural localisation was unusually persuasive.
What his work established
The 1886 operations established a principle that remains central to epilepsy surgery:
if seizures arise consistently from a localisable region, and that region can be removed without unacceptable loss of function, surgery may alter the course of the epilepsy.
Every modern technology has refined one part of that principle.
EEG improved localisation.
Imaging improved lesion detection.
Neuropsychology improved functional assessment.
Intracranial recording improved network definition.
But the basic surgical logic was already visible in Horsley’s work.
The central historical lesson
Victor Horsley’s importance does not lie simply in being ‘first’.
His real contribution was to make cerebral localisation actionable.
Jackson had shown that a seizure could reveal where abnormal activity began.
Ferrier had shown experimentally that different cortical regions produced different movements.
Horsley took the next step: he opened the skull, identified the suspected region and removed pathological cortex in an attempt to stop the seizures.
That moment marks the transition from explaining focal epilepsy to trying to cure it surgically.
The Montreal era would later transform the methods, but the operative idea was already in place by the 1880s.
Sources and further reading
Schijns OEMG et al. The start and development of epilepsy surgery in Europe: a historical review. Acta Neurochirurgica. 2015.
Full text: The start and development of epilepsy surgery in Europe. 2015.
Taylor DC. One hundred years of epilepsy surgery: Sir Victor Horsley’s contribution. Journal of Neurology, Neurosurgery & Psychiatry. 1986.
Sir Victor Horsley’s nineteenth-century operations at the National Hospital for Neurology and Neurosurgery, Queen Square. Journal of Neurosurgery. 2011.
Horsley was the first to use electrical stimulation of the human cerebral cortex intraoperatively. Surgical Neurology. 2003.
History of Neuropsychology Through Epilepsy Eyes. Epilepsy & Behavior. 2010.
Shorvon S. The evolution of epilepsy theory and practice at Queen Square between 1860 and 1910. Epilepsy & Behavior. 2014.
Sinha S, Danish SF. History and Technical Approaches and Considerations for Ablative Surgery for Epilepsy. Neurosurgery Clinics of North America. 2016.
The advent of epilepsy-directed neurosurgery: the early pioneers and who was first. 2023.
Historical evidence checked: September 2026.