No Man Alone: A Neurosurgeon's Life

"Each cerebral hemisphere’s cortical map of motor & sensory function of the contralateral side of your body is called a ‘homunculus,’ displaying a disproportionally magnified face and hand with a minified shoulder. This distorted hemi-imp was charted by Penfield in 1937 as he stimulated the “eloquent cortex” to find epileptic foci in patients whose seizures persisted despite medications. The road to the homunculus began after Penfield completed coaching the 1914 Princeton football team and then, as a Rhodes scholar, left the US to begin medical training at Oxford. In wartime Oxford, Penfield was taught by Charles Sherrington—arguably the World’s pre-eminent neurophysiologist, who in 1897 coined the term ‘synapse’. In 1916, while crossing the Channel to volunteer at a Red Cross hospital in France, Penfield’s ship, the S.S. Sussex, was torpedoed, badly shattering his leg. He convalesced at the home of Sir William Osler, the Regius Professor of Medicine at Oxford. At this halfway mark in medical school, Penfield left to finish at Johns Hopkins aspiring to follow in the footsteps of Sherrington and Osler – “the one in science and the other in medical practice and personal life.” Neurosurgery in the early 20th century was a small academically inbred discipline, but Osler, an internist, cut across specialty boundaries. During Cushing’s surgical residency at Hopkins from 1896 to 1899, the 47-year-old professor served as a mentor to the resident twenty years his junior. Penfield was an intern on Cushing’s surgical service in 1918-19, but his road diverged from the Cushing school of ever-improving surgical proficiency driven by pressing clinical puzzles such as how to diagnose a cerebral aneurysm before it fatally ruptures. Penfield resolved to learn about pathological lesions, and neuroanatomy: “Finally someday I would study two other things: the mystery of epilepsy, and how the human brain does what it does.” To accomplish this he sought the great clinical neuroscientists of England and Europe to particularly learn how to clinically examine the nervous system and the brain’s microscopic anatomy. At Queen Square, London’s pre-eminent neurologic hospital, in 1920 Gordon Holmes taught him to localize the cortical focus of epileptic attacks. In 1924 he met with Cajal and Pio del Rio-Hortego in Madrid to master the techniques of staining the cells of the brain. Cajal’s neuron doctrine of 1906 was the background, but if neurons were the building blocks of the central nervous system, Penfield needed to learn about the glia (‘glue’) that supports and holds them together. Sharing work tables, Rio-Hortega taught Penfield how to stain the glial cells: astrocytes, microglia, & oligodendroglia. In 1924 Penfield published confirmation of the existence of the hitherto ‘phantom’ oligodendroglia. No Man Alone recounts Penfield’s steep neuroscientific learning curve before he founded the Montreal Neurologic Institute in 1934 and mapped the cortical homunculus. Along the way, in 1928, he successfully removed the largest brain tumor—a right frontal lobe oligodendroglioma – he had ever encountered. And the patient was his sister! Penfield completed the final draft just three weeks before his death. Unlike many neuroscientists, he was a dualist, and No Man Alone narrates what he calls his “pilgrim’s progress” of “exploration of brain and mind.” Mysticism aside, Penfield was a maverick with an approach to neurosurgery that was very different from Cushing’s. Penfield began training when the electrical nature of epileptic discharges was unknown. The first electroencephalogram, or EEG—the gold standard of epilepsy diagnosis—would not be performed until 1924, but by the 1930s Penfield was using the EEG and bipolar electrodes to map the brain. I remain fascinated by his approach to the terra incognita of the brain forged by his caution (“first do no harm”) and counterweighted by his “desperate measures” such as cortical resections. These concepts intersected when Penfield performed a unilateral temporal lobectomy to control intractable complex partial seizures. In 1951 and 1952, two such patients unexpectedly sustained severe loss of their ability to retain recent memories. Penfield later found that each patient had prior unsuspected damage to the ‘normal’ opposite temporal lobe, setting the stage for our modern conception of the critical role of the bilateral temporal lobes/hippocampi for short-term/recent memory retention. Had William Beecher Scoville known this—or employed Penfield’s caution—on September 1, 1953, when he attempted to cure patient HM’s intractable epilepsy by bilateral removal of 8 cm. of hippocampus posterior to the tips of the temporal lobes, HM would not have been consigned to the “eternal present”—and the subject of the most detailed neuropsychological and neuroanatomical studies of any human to date."