A Science Odyssey
People and Discoveries

Wilder Penfield
1891 - 1976

Wilder Penfield was born in Spokane, Washington, and spent much of his youth in Hudson, Wisconsin. When he was 13, in 1904, his mother learned of the newly established Rhodes Scholarship. "This is just the thing for you," he recalled his mother saying with great confidence. He had to become an all-round scholar athlete. "The fact that my mind was really that of a plodder, and that my gangling body was slow and awkward, would be, it seemed, no obstacle whatever." But he accepted the challenge of this ambition, and preparing himself shaped the years to come. He went to Princeton University, not least because it was in the small state of New Jersey, and Rhodes Scholarships were awarded on a state by state basis. While there he decided to pursue medicine -- the profession of his grandfather and estranged father -- because it seemed the most direct way to "make the world a better place in which to live."

He did win the Rhodes Scholarship after all, and spent years training at Oxford, and in Spain, Germany, and New York, before becoming the first neurosurgeon in Montreal. His driving goal was to establish a neurological institute, where surgeons, laboratory researchers, phyiologists and all scientists in the field of neurology could work and share their knowledge. After a decade of fundraising and grantwriting, he established the Montreal Neurological Institute in 1934.

In the 1950s, Penfield was trying to treat patients with intractable epilepsy. Before an epileptic seizure, he knew, patients experience an "aura," a warning that the seizure is about to occur. Penfield thought if he could provoke this aura with a mild electric current on the brain, then he would have located the source of the seizure activity and could remove or destroy that bit of tissue. While patients were fully conscious, though anaesthetized, he opened their skulls and tried to pinpoint the source of their epilepsy.

His technique was often successful, but his experimental surgery led him to an even more dramatic discovery. Stimulation anywhere on the cerebral cortex could bring responses of one kind or another, but he found that only by stimulating the temporal lobes (the lower parts of the brain on each side) could he elicit meaningful, integrated responses such as memory, including sound, movement, and color. These memories were much more distinct than usual memory, and were often about things unremembered under ordinary circumstances. Yet if Penfield stimulated the same area again, the exact same memory popped up -- a certain song, the view from a childhood window -- each time. It seemed he had found a physical basis for memory, an "engram."

He also developed a map of the brain, often portrayed as a cartoon called the motor homunculus (miniature human being). This cartoon character has features drawn according to how much brain space they take up. Therefore, lips and fingers with their high number of nerve endings are larger than arms and legs.

Penfield was not only a groundbreaking researcher and devoted surgeon. During his life he was called "the greatest living Canadian." He devoted much thinking to the mystery of the mind, and continued until his death in 1976 to contemplate and question whether there is a scientific basis for the existence of the human soul.

"Brain surgery is a terrible profession. If I did not feel it will become different in my lifetime, I should hate it." (1921)

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