Epilepsy surgery did more than develop treatments for seizures. It became one of the most important ways scientists learned how movement, sensation, language and memory are organised in the living human brain.
Before human cortical mapping
Nineteenth-century experiments by Fritsch, Hitzig and Ferrier showed that electrical stimulation of animal cortex could evoke reproducible movements. Clinical observations by Broca, Jackson and others linked focal neurological signs and seizures with particular cortical regions.
From experiment to surgery
By the late nineteenth century Victor Horsley used cortical stimulation during operations on people with focal epilepsy. Harvey Cushing later refined awake mapping and demonstrated sensory responses during stimulation.
Penfield and the Montreal procedure
Wilder Penfield combined influences from Sherrington, Cushing and Otfrid Foerster. At the Montreal Neurological Institute he standardised awake cortical stimulation as part of surgery for focal epilepsy.
The homunculus and beyond
Repeated stimulation contributed to detailed maps of motor and sensory cortex and helped define language-related areas. Stimulation could also produce sensory, experiential and memory-like phenomena.
Mapping becomes a safety tool
Modern stimulation mapping is primarily a clinical safety technique used to identify cortex and networks that should be preserved during resection, often alongside neuropsychology, fMRI, tractography and invasive EEG.
Why epilepsy mattered to neuroscience
People undergoing epilepsy surgery gave researchers an unusual opportunity to study the relationship between electrical brain activity and conscious human function.
Related reading
Sources and further reading
- Brief history of electrical cortical stimulation
- The Montreal procedure
- History of neuropsychology through epilepsy eyes
Evidence checked: September 2026.