Wilder Graves Penfield

Wilder Graves Penfield was the son of Charles Samuel Penfield (1858-1913), a medical doctor, and Jean (Jefferson) Penfield. In 1899, when his father's medical practice failed and he was unable to support the family, his mother became a writer and Bible teacher and took his elder brother and sister and eight-year-old Wilder to live with her parents in Hudson, Wisconsin.

There he graduated, at the head of his class, from Galahad School, a private institution which his mother and three young teachers had organised. His mother worked here as a housekeeper. He graduated from Galahad in 1909. He then entered Princeton University, determined to make himself an all-round scholar, athlete, and leader so that he might qualify for a Rhodes scholarship. Howeverm, the best he could do in football was to qualify as a substitute on the freshman team. That winter he took up wrestling, won the interclass freshman-sophomore wrestling match, and eventually found a place on the varsity football team as a first-string tackle. He completed his bachelor’s degree in philosophy at Princeton in 1913.

Into medicine
Penfield had previously thought that he would never want to enter the profession in which his father had failed. But at the end of his sophomore year, influenced by Professor Edwin Grant Conklin's (1863-1952) biology lectures – and a long-standing desire to help his fellow man inculcated in him by his mother – led him to decide on a career in medicine.

Penfield looked forward to beginning his medical education at the University of Oxford in England, but lost out for the Rhodes Scholarship from New Jersey. Instead, he devoted the year after graduation to earning money for his medical education by coaching the Princeton freshman football team and then teaching at the Galahad School.

In the middle of the year, he received word that a Rhodes Scholarship for the following year had been awarded him, and he was accepted for admission to Oxford's Merton College, which granted him special permission to defer his entrance until the end of the autumn of 1914 so that he might fulfil an agreement to coach the Princeton varsity football team.

In January 1915, as a member of Merton College, he enrolled in courses that would assist in his completion of a medical degree at Johns Hopkins University, which he planned to enter on his return to the United States. He was assisted by Sir William Osler (1849-1919), Oxford’s Regius Professor of Medicine who had concluded that Penfield could become a good doctor. Anxious to help, Osler invited the young American to accompany him on medical consultations around England from one hospital to another. Through his association with Osler, Penfield came to regard medicine as mankind's most noble calling.

Penfield was also greatly influenced by Sir Charles Scott Sherrington (1857-1952). Through Sherrington’s lectures Penfield was introduced to the study of the brain. Sherrington made him realize that in the nervous system was ``the unexplored field – the undiscovered country in which the mystery of the mind of man might some day be explained.''

Torpedoed in the English Channel
During the Christmas break from studies at Oxford, in late 1915, Penfield worked briefly as a volunteer in a Red Cross hospital. When he was returning to this Red Cross work in late March 1916, after the winter term at Oxford, the ship on which he was travelling was blown up by a German torpedo in the English Channel. Although he was erroneously reported dead and his obituary was published in an American newspaper, he survived the torpedo attack but spent three weeks in a hospital in Dover, England, and several weeks recuperating at Sir William Osler’s residence in Oxford.

An American in Paris, Baltimore and Oxford
After two years at Oxford, Penfield returned to the United States and began his final years of study at Johns Hopkins Medical School. In April 1917, however, the United States declared war on Germany and entered the First World War. The following June, Penfield married Helen Kermott (1891-1978). Several weeks later he and his wife took a ship to France where they both worked in an American Red Cross hospital in Paris.

In late 1917 they returned to the United States. Penfield completed his medical studies at Johns Hopkins and received his medical degree in 1918. The following year he was a surgical intern at the Peter Bent Brigham Hospital in Boston, serving an apprenticeship under brain surgeon Harvey Cushing (1869-1939). But the memory of the ``undiscovered country'' he had glimpsed through Sherrington's lectures continued to intrigue him. He accordingly returned to Oxford for the third and final year of his Rhodes scholarship as a graduate student in neurophysiology under Sherrington and followed that with a year as a research fellow in neurology at the National Hospital in London.

The young surgeon
In 1921, when this period of his advanced research was finished successfully, Penfield and his family, which by this time included two children, returned to the U.S. He rejected a lucrative position as a surgeon at the Henry Ford Hospital in Detroit – because it would have afforded him no opportunity for research – and accepted a post as associate in surgery at Columbia University and Columbia Presbyterian Hospital in New York. There he developed his surgical techniques under Allen Oldfather Whipple (1881-1963), and organized and pursued research in a laboratory of neurocytology.

The Spanish and German connection
Penfield's interest in epilepsy began during his surgical work in New York in the 1920s. In 1924 he studied four months in Madrid with the Spanish neurohistologist Pio del Rio-Hortega (1882-1945) in his laboratory. Here he learned metallic staining techniques that yielded new information on the glia, the supporting cells of the nervous system.

In 1928 he visited Otfrid Foerster (1873-1941) in Germany. Foerster was considered an expert on epilepsy and had developed a strong interest in the surgical management of neurological diseases. From him Penfield learned the method of excising brain scars to relieve focal epilepsy. Foerster also produced the first cortical map of the entire cerebral cortex, published together with Penfield in 1930.

Penfield adopted Foerster's technique of local anaesthesia and electrical stimulation to map the human cortex, but greatly extended Foerster’s work by discovering other areas of cortex subserving speech, hearing, vision and, perhaps most crucial of all, memory function.

The new Canadian
During his postgraduate years in Oxford and London, Penfield had turned from experimental neurophysiology toward neurosurgery because he believed that, since the neurosurgeon could lay bare the living human brain, he should be able to study and influence the brain's physiological activity and thus become "a neurologist-in-action.'' As he came to realize that he could not carry out an effective approach to knowledge of the human brain and make use of that knowledge all by himself, he began to dream of organizing an institute where neurologists, neurosurgeons and neuropathologists would work together with the kind of team work he had learned as a football player and coach.

Thinking he might be better able to realize this dream in Montreal, Canada, Penfield and his neurosurgical partner, William Vernon Cone (1897-1959), moved to Canada to work in the Royal Victoria Hospital and Montreal General Hospitals. Penfield also joined the medical faculty of McGill University. He was 37 years old.

The Montreal Institute of Neurology
A few months after his arrival in Montreal, Penfield was called upon to remove a tumour from the brain of his sister Ruth. After finding that the tumour was malignant and far advanced, he performed a more radical operation than most neurosurgeons would have dared to attempt, but could not safely remove all of the malignant cells. Although the operation made it possible for his sister to enjoy a normal life again, the symptoms eventually returned and she died three years later.

The difficulties of his sister's case spurred him to make his first effort to realize his dream of an endowed neurological institute for "investigation of the brain and mind as a way to human betterment."' His initial application to the Rockefeller Foundation was not successful, but by 1934 the Foundation finally agreed to join with the Province of Quebec, the City of Montreal, and private donors to help financially in the implementation of Penfield’s plan to establish the Montreal Neurological Institute. The contribution from the Rockefeller Foundation was a grant of $1,232,000. The Montreal Institute of Neurology was opened in 1934, the first of its kind in the world. It soon became a famous international centre for teaching, research and treatment related to diseases of the nervous system. He was its director until 1960.

On October 11, 2002, the Helen Penfield Atrium, named in honour of his wife, was opened at the Montreal Neurological Institute.

His first concern was always the patient
Penfield's "distinguished contributions,'' his successor, William Howard Feindel (born 1918), said, "were recognized as unique by his neurosurgical and scientific colleagues.'' The eminent British neurologist and 1932 Nobel Laureate Edgar Douglas Adrian (1899-1977) described Penfield as "a skilled neurosurgeon, a distinguished scientist, and a clear and engaging writer'' with qualities of leadership that attracted `"devoted colleagues,'' but that "his first concern was always the patient who needed his surgical skill.''

The Montreal Procedure
In the 1940s and 1950s, Penfield and his associates defined the anatomical and pathological features of temporal lobe seizures originating in mesial temporal structures, pioneering the technique of systematic electrical stimulation at various points of the cerebral cortex in the surgical treatment of focal epilepsy. The procedure required that the patients remain conscious, receiving only local anaesthesia. The patient's so responses to Penfield's gentle applications of current enabled Penfield to identify, in many cases, the precise location of the damaged brain tissues that were causing epileptic seizures. As he did this he was able to map areas of the brain in terms of their respective functions.

This new surgical approach, with anterior temporal lobectomy including removal of the amygdala and hippocampus, became known as the "Montreal Procedure. The opepration was adopted worldwide and has postoperative cessation of seizures in more than 75% of patients. Penfield performed more operations for epilepsy than any other surgeon in the world to that time. Under his directorship, the institute treated 1,132 patients.

Memories of things past
Through his research Penfield developed an interest in the connection between the brain and the human mind. This was the topic of his book The Mystery of the Mind, published in 1975. Carefully probing the brain during his early research, he found that administration of a mild electric shock to one of the temporal lobes could, miraculously it seemed, cause the patient to recall precise personal experiences that had long been forgotten. This is often referred to as Proustian "flashback" effects.

Based on his observations, Penfield concluded that all experience must be permanently stored in the brain in its original form.

His second career
Penfield retired from the McGill medical faculty in 1954, but he continued to serve as director of the Neurological Institute and to lecture frequently. He visited Princeton in 1956 to deliver the Vanuxem lectures, later published by Princeton University Press as Speech and Brain Mechanisms. He also travelled to Russia, India, and China in successive years as an invited lecturer before scientific groups. At the same time, he began a second career, as he completely rewrote his late mother's novel, Story of Sari (based on a Biblical tale), which was published under the title No Other Gods.

He retired as director of the Neurological Institute in 1960, and that same year he published The Torch, a biographical novel about Hippocrates. Three years later, at age seventy-two, he brought out The Second Career, a collection of essays and addresses reflecting his myriad interests and encouraging others to use retirement for the development of a new career.

Three weeks before his death at the age of eighty-five on April 5, 1976, Penfield completed the draft of his autobiography, No Man Alone, a phrase repeated frequently in the book to underline his emphasis on the team approach to neurological research and treatment. Published in 1977, his final work was dedicated ``with affection and gratitude'' to the memory of his mother who had helped make it possible for him ``to see things as they were'' by preserving, editing, and typing the letters he had written her almost every week from 1909, when he entered Princeton, until her death in 1935.

A man of honours
Honours were bestowed on Penfield by societies, universities, and governments in North America, Europe, and Asia. President of the Royal College of Physicians and Surgeons of Canada and of the American Neurological Association, he was a fellow of the prestigious Royal Society of London and twenty-five other scientific and professional organizations and a recipient of honorary degrees from as many universities, among them Princeton, Oxford, McGill, and Montreal. He was also awarded half a dozen prizes here and abroad and was the first recipient of the $50,000 Royal Bank Centennial Award. Twice decorated by Canada, he was also awarded the United States Medal of Freedom, crosses of the French Legion of Honour and the Greek Legion of George I -- and the British Order of Merit, which is conferred on only twenty-four living persons. He received the Lannelongue Medal of France in 1958, the Lister Medal of the Royal College of Surgeons in 1961.

One evening in the late eighteenth century an Italian woman stood in her kitchen watching the frog’s legs which she was preparing for the evening meal. “Look at those muscles moving. . . . They always seem to come alive when I hang them on the copper wire.”
Her husband [Luigi Galvani] looked. . . . The cut end of the frog’s nerve was in contact with the copper wire, and electric current produced by the contact was passing along the nerve to the muscle. As a result, the muscle was twitching and contracting . . .
He had discovered the key to electricity, and to nerve conduction, and to muscle action. Here was the basis of all animal movement, reflex and voluntary, in frog and man.
The Second Career, “The Physiological Basis of the Mind”

There are times when compassion should prompt us to forego prolonged and costly treatment. If a man must die, he has the right to die in peace, as he would prefer to die if asked. Positive action to take a life is not permitted. But the negative decisions that ease and shorten suffering have always been ours to make.
The Second Career, “A Doctor’s Philosophy”

In spite of all these disquieting triumphs in the field of natural science, it’s astonishing how little man has learned about himself, and how much there is to learn. How little we know about this brain which made social evolution possible, and of the mind. How little we know of the nature and spirit of man and God. We stand now before this inner frontier of ignorance. If we could pass it, we might well discover the meaning of life and understand man’s destiny.
Dartmouth Convocation on The Great Issues of Conscience
in Modern Medicine (1960), Third Panel Discussion.

It would seem that modern science has not really changed man’s normal span of life. Nineteen hundred years ago, Pliny the Elder wrote that centenarians were common enough at that time in Rome. He even told of an actress who boasted that she had survived a hundred years. The change which we should recognize in this generation is that more men and women reach life’s true goal, fulfilling the cycle set for us, bypassing the plagues and disease and famine.
The Second Career, Chapter I.

It is fair to say that science provides no method of controlling the mind. Scientific work on the brain does not explain the mind – not yet. Neither the work of Pavlov on conditioned reflexes nor that of any other worker has proven the thesis of materialism. Surgeons can remove areas of brain, physicians can destroy or deaden it with drugs and produce unpredictable fantasies, but they cannot force it to do their bidding.
Dartmouth Convocation on The Great Issues of Conscience
in Modern Medicine (1960), Third Panel Discussion.

Toward the end, senescence with its comforting drowsiness closes stealthily one door after another. And so when death comes at last, it may not be unwelcome after all. Science has not changed these things. The span of life, for those who escape its early perils, is about the same today as when David played on his harp before King Saul.
The Second Career, Chapter I.

"When one of these flashbacks was reported to me by a conscious patient, I was incredulous . . . for example, when a mother told me she was suddenly aware, as my electrode touched the cortex, of being in the kitchen listening to the voice of her little boy who was playing outside in the yard."

"For myself, after a professional lifetime spent i trying to discover how the brain accounts for the mind, it comes as a surprise now to discover, during this final examination of the evidence, that the dualist hypothesis seems the more reasonable of the two possible explanations. Mind comes into action and goes out of action with the highest brain-mechanism, it is true. But the mind has energy. The form of that energy is different from that of neuronal potentials that travel the axone pathways. There I must leave it."
The Mystery of the Mind

‘Work today and be happy tomorrow’ – that’s the physician’s rule to life.
The Torch, Chapter 10.

Hippocrates . . . swept away religious superstition and the unprovable assumptions of philosophy, to record what he could see and hear and fee. He based his reasoning on observed fact and learned to assist the body in its vital struggle against disease.
The Second Career, “Aegean Cradle of Medicine”

He [Lord Lister] was a scientist by virtue of his habit of thought . . . he did not accept the pronouncements and the explanations of the surgeons and physicians about him, or who had gone before him, without critical consideration of the evidence . . . He depended on those things that could be proven. Thus his thinking about clinical problems was scientific rather than authoritarian. T
he Second Career, “Surgery and Science
Referring to Joseph, Lord Lister, 1827-1912.

[Ambroise] Paré . . . was guided by fearless compassion for the suffering of his patients, and by practical experiment. Thus it was that he established better methods of treatment and forbade gratuitous interference.
The Second Career, “Surgery and Science

Rest, with nothing else, results in rust. It corrodes the mechanisms of the brain. The rhubarb that no one picks goes to seed.
The Second Career, Chapter I

The trouble is not in science but in the uses man make of it. Doctor and layman alike must learn wisdom in their employment of science, whether this applies to atom bombs or blood transfusion.
The Second Career, “A Doctor’s Philosophy”

Every specialist, whatever his profession, skill or business may be, can improve his performance by broadening his base.
The Second Career, “The Use of Idleness”

The undergraduate usually prefers brief and positive statements of the “facts” made by a professor who hides his doubts beneath a mantle of shining authority. It gives the student such a sense of security, especially in regard to examinations.
The Second Career, “Sir Charles Sherrington”

The Egyptians made a fatal mistake. They wrote textbooks, the hermetic books. They made another and more serious mistake, and that was to believe that the textbooks were correct. So they forbade physicians, at peril of their lives, to depart in any way from the treatment prescribed in the hermetic books . . . The experiment demonstrated that standardization can halt advance but that it does not in any way hinder retrogression.
The Second Career, “Neurosurgery – Yesterday, Today and Tomorrow.

Don’t always be a physician! . . . The help you need is the help a wife could give you. Through her you would learn the other half of life. Without her you may live to be only half man . . . “Nothing in excess.” Too much medicine, too much work, even too much kindly service may be excessive.
The Torch, Chapter 5

"Rest, with nothing else, results in rust.''

“My wife made of our family and of my professional career a life project of managing and teaching. Thanks to that, many things came to us. Happiness was one of them. Perhaps one might say that such success as came to me professionally was another.”
On his wife, Helen Kermott Penfield
From No Man Alone – A Neurosurgeon’s Life

You physicians are a group apart. You are a strange race. The wife of a physician should be as different from other women as her husband is different from other men.
She needs more than beauty and poetry to support her through the years of medical practice. She must know how to work. She must be able to understand and to suggest. She must love you, but more than that, she must love your work. Otherwise, she will not be happy, nor you. Otherwise you can never do all that you want to do for the sick.
The Torch, Chapter 8

It may be that physicians need a woman’s guidance and companionship more than other men. Happiness comes to them as a reward, secondarily. There are other urges than the pursuit of happiness that keep them going. But what can a physician do? No woman would marry him if she were in her right mind.
The Torch, Chapter 10

• Cerebral cicatrix: the reaction of neuroglia and microglia to brain wounds.
  By Pio del Rio-Hortega and W. Penfield.
  Bulletin of the Johns Hopkins Hospital, Baltimore, 1927, 41: 278-303.
• Der Narbenzug am und im Gehirn bei traumatischer Epilepsie in seiner Bedeutung für das Zustandekommen der Anfälle und für die therapeutische Bekämpfung derselben.
  By Otfrid Foerster and W. Penfield. Berlin, J. Springer, 1930.
  Zeitschrift fur die Gesamte Neurologie und Psychiatrie, 1930, 125: 475-572.
• The structural basis of traumatic epilepsy and results of radical operations.
  By Otfrid Foerster and W. Penfield. Brain 1930, 53: 99-119.
• Cytology and Cellular Pathology of the Nervous System.
  Edited by W. Penfield. 3 volumes. New York, Paul B. Hoeber, 1932.
• The significance of the Montreal Neurological Institute.
  In: Neurological Biographies and Addresses; Foundation Volume.
  Published for the Staff, to Commemorate the Opening of the Montreal Neurological Institute of McGill University (on 27th September, 1934).
  London: Oxford University Press, 1937: 37-54.
• Somatic motor and sensory representation in the cerebral cortex of man as studied by electrical stimulation. With E. Boldrey. Brain, 1937, 60: 389-443.
• The cerebral cortex in man. I. The cerebral cortex and consciousness.
  Archives of Neurology and Psychiatry, 1938, 40: 417-442.
• Epilepsy and Cerebral Localization; A Study of the Mechanism, Treatment and Prevention of Epileptic Seizures.
  With Theodore Charles Erickson (1906-1986).
  Springfield, IL: Charles C Thomas, 1941.
• Calcifying epileptogenic lesions. Hemangioma calificants; report of a case.
  With Arthur Allen Ward (1916-1997).
  Archives of Neurology and Psychiatry, 1948, 60: 20-36.
• The Cerebral Cortex of Man. A Clinical Study of Localization of Function.
  With Theodore Rasmussen. New York, NY: Macmillan, 1950.
• Surgical therapy of temporal lobe seizures.
  With Herman F. Flanigin. Archives of Neurology and Psychiatry, 1950, 64: 491-500.
  Flanigin was one of Penfield's students at the Montreal Neurological Institute.
• Epileptic automatism and the centrencephalic integrating system.
  Research Publications - Association for Research in Nervous and Mental Disease, 1952, 30: 513-528; 1952
• Localization of epileptic discharge in temporal lobe automatism.
  By W. Feindel, W. Penfield, and H. Jasper.
  Transactions of the American Neurological Association, 1952, 77: 14-17.
• Temporal lobe seizures and the technique of subtotal temporal lobectomy.
  With M. Baldwin. Annals of Surgery, 1952, 136: 625-634.
• Incisural sclerosis and temporal lobe seizures produced by hippocampal herniation. By K. M. Earle, M. Baldwin and W. Penfield.
  Archives of Neurology and Psychiatry, Chicago, 1953, 69: 27-42.
• Localization of discharge in temporal lobe automatism.
  By W. Feindel and W. Penfield.
  Archives of Neurology and Psychiatry, 1954, 72: 605-630.
• No Other Gods. Novel. 1954.
• Epilepsy and the Functional Anatomy of the Human Brain.
  With Herbert Jasper. Boston, Little, Brown & Co., 1954.
  This comprehensive monograph on the mechanism and surgical treatment of epileptic seizures is considered Penfield's most substantial scientific work.
• The insula: further observations on its function.
  With M. E. Faulk. Brain, 1955, 78: 445-470.
• Prospect and Retrospect in Neurology. Second Foundation Volume.
  Boston and Toronto: Little, Brown and Co., 1955: 53-57.
• Epileptogenic lesions.
  Acta Neurologica Psychiatrica Belgica, 1956, 56: 75-88.
• Memory deficit produced by bilateral lesions in the hippocampal zone.
  With Brenda Milner (born 1918).
  Archives of Neurology and Psychiatry, 1958, 79: 475-497.
• Excitable Cortex in Conscious Man. 1958.
• Speech and Brain-Mechanisms.
  With L. Robert. Princeton, NJ: Princeton University Press, 1959.
• Dr. William Vernon Cone: 1897-1959.
  The Canadian Medical Association Journal, July 1, 1959, 81 (1): 55-56.
• The Torch. Novel. Boston, Little Brown, 1960.
  A romantic historical novel about Hippocrates.
• The Second Career. 1963.
• Manipulation hemiplegia. An untoward complication in the surgery of focal epilepsy. With R. A. Lende and T. Rasmussen. Journal of Neurosurgery, 1961, 18: 760-777.
• The cerebral cortex and consciousness.
  Journal of Neurosurgery, 1965, 22: 201.
  Originally published in The Harvey Lectures, 35, 1937.
• The Difficult Art of Giving. 1966.
  A biography of noted American Physician Alan Gregg (1890-1957), director of the medical sciences division of the Rockefeller Foundation, who had engineered the grant that had made the Montreal Neurological Institute possible.
• Epilepsy, the great teacher: The progress of one pupil.
  Acta neurologica Scandinavica, Copenhagen, 1967, 43: 1-10.
• Man and His Family.
• Lights in the great darkness. The 1971 Harvey Cushing Oration.
  Journal of Neurosurgery, 1971, 35: 377-383.
• No man alone. A Neurosurgeon’s Life. Boston, Little Brown & Co.,1977.
• Memory. Autopsy findings and comments on the role of hippocampus in experiential recall.
  With G. Mathieson. Archives of Neurology, 1974, 31: 145-154.
• The Mystery of the Mind.
  An account for laymen of his investigation of the brain for almost forty years. Dedicated to Sir Charles Sherrington. Princeton University Press in 1975. Works by others:
• Pio del Rio-Hortega (1882-1945)
  Microglia.
  In: W. Penfield, editor: Cytology and cellular pathology of the nervous system.
  Hoeber, New York, 1932. Volume 2: 482-534. Biographical etc:
• Modern Men of Science. 1966.
• Alexander Leitch (1900-1987):
  A Princeton Companion. Princeton University Press, 1978.
• Sixto Obrador (1911-1978):
  Penfield y la escuela de Cajal. Penfield y su relación con Cajal y Río Hortega.
  Revista española de oto-neuro-oftalmologia y neurocirugia, Valencia, January-February 1975, 33 (191): 38-53.
  [Penfield and the school of Cajal. Penfield and his relation to Cajal and Rio-Hortega]
• David Sclater Lewis (1886-1976):
  Royal Victoria Hospital 1887-1947, Chapter 11: The Montreal Neurological Institute –Its Earlier Days. Montreal McGill University Press 1969: 297-308.
  
  
• Theodore Rasmussen (1910-2002):
  Wilder Penfield, 1891-1976. Journal of Neurosurgery, 1976, 45: 249.
  Theodore Rasmussen in 1960 succeeded Penfield as director of the Montreal Neurological Institute.
• William Feindel (born 1918):
  Wilder Penfield : his legacy to neurology. To praise an absent friend.
  The Canadian Medical Association Journal, June 18, 1977, 116, 12: 1365-1377.
• W. Feindel:
  Wilder Penfield (1891-1976): The Man and His Work. Neurosurgery, 1966, 1: 93.
• John Carew Eccles (1903-1997) and W. Feindel:
  Wilder Graves Penfield (1891-1976).
  In: Sir Kingsley Dunham, A. Neuberger, A. R. Collar, et al, editors: Biographical Memoirs of Fellows of the Royal Society, London, 1978, 24: 472-513.
• W. Feindel:
  Historical Vignette: The Montreal Neurological Institute.
  Journal of Neurosurgery, Charlottesville, Virginia, 1991, 75: 821-822.
• Mark C. Preul, W. Feindel:
  Historical Vignette: Origins of Wilder Penfield’s surgical technique.
  Journal of Neurosurgery,1991, 75: 812-20.
• W. Feindel:
  Neurosurgery at the Montreal Neurological Institute and McGill University Hospitals.
  Neurosurgery, 1996, 39: 830-839.
• Norman H. Horwitz:
  Wilder Penfield (1891-1976). Neurosurgery, 1997, 41:314.