Patient H.M.

by Luke Dittrich

  The Neuro, as the institute was commonly known, was the most prestigious center for neurosurgery in Canada. It was helmed by Canada’s most renowned neurosurgeon, an imperious American transplant named Wilder Penfield. Penfield had pioneered a new surgical method for the treatment of epilepsy, one that involved targeting the temporal lobes of the brain. Because the general function of the temporal lobes was a mystery, Penfield decided that it would be good to have a psychologist study his patients before and after their operations, to see whether his surgical lesions were causing any notable changes beyond their purely therapeutic effects. He only had room for one researcher. Hebb told her that the job was hers if she wanted it.

  Brenda Milner had spent her academic career up until then trying to glean a deeper understanding of the hidden processes taking place inside the black box of the human skull. As soon as she arrived at the Neuro, the black box was, for the first time, flung wide open to her.

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  In 1892, at a meeting of the New York Neurological Society, a prominent doctor named Joseph Price presented a paper called “The Surgical Treatment of Epilepsy,” which was later published in The Journal of Nervous and Mental Disease. In his introduction, Price described the long, hard road that generations of doctors had walked in their attempts to treat this stubborn and ancient sickness. “Its history, from a therapeutical standpoint,” he wrote, “is one that has taxed the efforts of supremest superstition and defied the resources of scientific medication. Its treatment has been one of trial and disappointment, for it still remains one of the greatest opprobria of medicine.”

  There were, however, grounds for optimism. The age of reason had dawned, and superstitions were dropping away. The principal causes of the disease, Price declared, were finally coming to light.

  “Debauchery leads to it,” he said. “Young widows are prone to it, and its origin outside of physical causes may be traced to amorous songs and certain stimulants, such as chocolate and coffee.” Onanism, Price continued, was also associated with many cases of epilepsy, and in those cases there was a straightforward remedy. “In women, efforts in a surgical way have long been tried for its relief,” he noted. “One table I have consulted gives as high as 73.7 per cent of cases cured of masturbation by clitoridectomy. This surely makes it not presumptive in its claims for recognition.”

  Not all epilepsies had their roots in lust. Price noted that some epileptic fits were characterized by guttural, convulsive noises originating in the throat. This presented surgeons with an obvious area of attack. “Tracheotomy,” he said, “was urged by Marshall Hall and others on the ground that many convulsions began in and were limited to the larynx.” Other surgical approaches that he listed with approval included male castration and female ovariectomies, the benefits of which, he noted, would accrue to the epileptics as well as to the societies in which they lived. “So far as unsexing an epileptic is concerned,” he continued, “I do not understand how or why there is reason to feel compunction at such a suggestion. I can hardly question the protective value to society, not only of forbidding epileptics to marry, but of rendering them unable to procreate.” The amputation of the left arm also reportedly had occasional success, and nonsurgical treatments included doses of belladonna, a plant-derived poison with its roots in Europe, and curare, a plant-derived poison with its roots in South America. Leeches, too, showed promise.

  Price wrote about both medical and surgical treatments for epilepsy, though he tended to favor the surgical approach. “Operation has the best of the argument,” he wrote. “Out of seventy-one cases treated medically, and out of a second series of seventy-one treated surgically, the statistics as exhibited in my collection, the advantage is all with the surgical treatment, as in these four all were at least benefited, while in the medical series a great proportion showed no effect at all, and some grew worse. The exact percentage someone may calculate who has a greater taste for such work than I.”

  Six decades later, when Brenda Milner arrived at the Montreal Neurological Institute, epilepsy treatments still consisted of an assortment of medications and operations, although the medications and the operations had changed. Doctors had by then zeroed in on the disease’s true point of origin, which, it turned out, had never been in the nether regions, the throat, or the limbs. Instead, the modern medical establishment rediscovered that, as Hippocrates had prophesied 2,400 years earlier, “the brain is the cause of this affection.”

  While the fact that epilepsy is a brain disorder may seem obvious today, that knowledge was hard-won and was built, once again, upon the backs of broken men and women whose damaged brains illuminated the functions of our own. The 1861 postmortem examination of the brain of Monsieur Tan, the monosyllabic patient discovered by the French doctor Paul Broca, provided neurologists with the first clear evidence that a specific faculty—in this case, speech—was localized in a specific patch of cortex, and it wasn’t long before doctors interested in the etiology of epilepsy correctly guessed that epileptic seizures—which often consistently provoked convulsions of speech or movement—might be caused by damage to the associated parts of the brain. A complementary development, also in the late 1800s, was the discovery that by electrically stimulating portions of exposed brains of living humans or animals, it was possible to create automatic, convulsive physical responses: Shock a particular portion of the surface of the brain and a patient’s fingers might twitch. Shock another and his biceps might flex. Slowly doctors developed the concept that epilepsy might sometimes result from a similar effect, with portions of the brain discharging uncontrollably as though touched with an electrode. This convulsiveness might be caused, they surmised, by tumors or scar tissue or other damage to the brain. Careful observation of a patient’s seizures could give surgeons a clue to where to look for this “epileptic focus”: If a patient tended to convulse on the left side, for example, there might be reason to believe that there was an abnormality in the brain’s right hemisphere. Surgeons would then simply open the right side of the patient’s skull and look around for damage. If they found the problem, they would take it out.

  Eventually, surgeons began using electrical stimulation during the operations, helping them identify the functional components of the brain before they made their irrevocable cuts, ensuring that they wouldn’t, for example, inadvertently slice away the patient’s ability to hear or taste or see. And while electrically stimulating the brain became an essential part of making brain surgery safer, it also became a key tool in exploring the organ’s subtle geography. Neurosurgeons became neural cartographers, charting out not just the broad contours of the motor cortex, for example, but all the intricate differentiations within it, right down to which part of the brain controlled the fingers as opposed to the toes.

  In 1950, when Brenda Milner arrived at the Montreal Neurological Institute, Wilder Penfield, the institute’s founder and chief neurosurgeon, was the king of the mapmakers.

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  Like anyone interested in how the brain works, Milner had seen and studied Wilder Penfield’s “homunculi” illustrations. These illustrations, published in Penfield’s bestselling book, The Cerebral Cortex of Man, and reproduced in dozens of academic and nonacademic publications, were simple but powerful guides to neuroanatomical function. There were two diagrams, each showing a grotesque cartoon figure of a man draped over a portion of a human brain. In the first diagram, the man represented the motor cortex, which is a narrow strip of neural tissue about three-quarters of an inch wide that arches over the top of one side of the brain, dips slightly in the middle, then proceeds down over the next hemisphere. Since the motor cortex is more or less equally represented bilaterally, Penfield’s diagram showed only one hemisphere. At the very top, his homunculus dipped its toes into the chasm between the hemispheres, the so-called central sulcus, because that is the portion of the cortex that would cause Penfield’s patients’ toes to twitch when he stimulated it with his electrode. Next, in predictable nursery-rhyme order, came the an
kles, knees, hips, and trunk, right up to the homunculus’s shoulder, which rests on the spot right where the brain’s flattish top begins to slope noticeably downward. Then things got strange. First of all, instead of proceeding from the shoulders to the neck, as you might expect, Penfield’s homunculus was for the moment headless, as the elbows and wrist came next, draped over the next centimeter or so of motor cortex. And then, blown out of all proportion, occupying more space than the entirety of every other part of the body that came before it: the hand. The hand was enormous. Just the heel of the palm took up more cerebral real estate than the entire leg, and its thumb would dwarf Little Jack Horner’s. The tip of the thumbnail occupied a spot about halfway down the cortex, and about a millimeter below it the homunculus’s head finally made its appearance. The brow was truncated, almost Neanderthal, because Penfield was only able to elicit brow twitches from a lilliputian patch of neurons. Its ears were tiny, almost invisible, for the same reason. Its mouth, however, was almost as gigantic as its hand. Penfield had discovered, through the application of electric shocks to the brains of his patients, that “the cortical representations of the act of eating” were spread widely across a large portion of the surface of the motor cortex, so that applying an electrode to one spot might cause, for example, “mastication with movement of tongue,” while giving a jolt to another spot nearby might cause “mastication with vocalization.”

  Penfield’s second homunculus complemented his first and represented the somatosensory as opposed to the motor cortex, using another cartoon to illustrate the portions of the brain that govern our sense of touch. The somatosensory cortex was roughly the same size as the motor cortex and lay just behind it. If you looked at a girl wearing two headbands, one behind the other, the somatosensory cortex would lie under the second one, slightly closer to the back of her head. Penfield’s careful mapmaking had revealed that the cortical representation of the different body parts along the somatosensory cortex ran almost exactly parallel to the cortical representation of those same body parts along the motor cortex. So if he jolted a point on a patient’s motor cortex that caused the patient’s ankle to flex, then applied the electrode to a point about a half-inch behind the first one, the patient would usually feel as though someone were touching his ankle. There were a few exceptions. For example, Penfield’s motor cortex homunculus lacked genitalia, while his somatosensory homunculus had a little penis nestled in the central sulcus, just below its toes.

  The most important distinctions between Penfield’s maps of the motor cortex and the somatosensory cortex, however, were the methods by which the maps were obtained. Penfield had been able to chart the motor cortex by simple observation: When he stimulated a point on the patient’s brain, he would note what part of the patient’s body moved, and make a record of it. The mapping of the somatosensory cortex, however, required the active participation of the patient. Patients would have to report to Penfield where, exactly, they felt as though their bodies were being touched. And this meant, of course, that the patients had to be conscious.

  Penfield was not the first neurosurgeon to operate on conscious patients. In the late 1800s, a British surgeon named Victor Horsley found that patients could withstand brain surgery while awake so long as large amounts of cocaine were first injected into their dura. By Penfield’s time, local anesthesia was almost the norm, injections of synthetically derived novocaine having supplanted the coca-plant-based alternatives. But although Penfield was not the first to keep his patients awake on the operating table or to stimulate their brains electrically, a unique combination of reportorial meticulousness and operative approach made his work groundbreaking. While other surgeons typically operated through small holes in the skull and could therefore only see a small portion of the surface of the brain, Penfield preferred to open a large “bone flap,” roughly five by four inches, exposing a prodigious expanse of cortex that he could then cut or stimulate at will. This allowed him to make more progress in charting the mysterious territories inside our skulls than any who’d come before him.

  As early as 1928, Penfield began to muse about the possibility of “an institute where neurologists could work with neurosurgeons and where basic scientists would join the common cause, bringing new approaches.” He lobbied for it relentlessly until, in 1934, with the help of millions of dollars from the Rockefeller Foundation, the Montreal Neurological Institute finally opened its doors. There was nothing like it: a place where scientists and medical doctors were thrown together and jumbled about until the distinctions between them blurred. Neurosurgeons, neurologists, psychiatrists…each approached the study of the brain from a different angle, and at the Neuro they could combine their individual strengths, and compensate for their individual weaknesses, in pursuit of a common cause. And that cause was straightforward and far-reaching: The Neuro, Penfield hoped, “would open the way to brain physiology and psychology. And then, sometime perhaps, we would make a more effective approach to the mind of man.”

  When Brenda Milner walked through the front door of the Neuro in 1950, it had already established itself as one of the world’s leading centers for the interdisciplinary study of the brain. Penfield’s ambitions for the place were literally carved in stone: One of the first things Milner saw, climbing up the steps into the atrium, was a huge marble statue of the goddess Nature, who was coyly pulling open her robes, naked underneath, symbolically revealing herself to science. The statue, like the rest of the atrium, was commissioned personally by Penfield in collaboration with an architect, and as Milner looked around, her eyes would have caught on dozens of other subtle messages hidden around the room, a secret code readable only by those fluent in the language of the brain. A decorative design on the ceiling revealed itself, upon closer inspection, to be an artistic representation of the cells of the cerebellum, and in the center of the ceiling was the institute’s logo, an emblem of a ram’s head surrounded by odd symbols. Only a few of those entering here would remember that Aries, the astrological ram, ruled over the brain, and fewer still that the odd symbols were hieroglyphs lifted from the Edwin Smith Papyrus and considered to be the first written representations of the word brain.

  Her degree adviser, Donald Hebb, had given Milner two directives prior to her arrival. One, to be as helpful as possible. Two, don’t get in anyone’s way. She would recall spending her first couple of weeks there “hugging the walls.” Eventually, however, it dawned on her that to follow the first directive she would have to ignore the second, and so she began to step forward and speak up. This was not easy. Wilder Penfield turned fifty-nine in 1950, but he was if anything a more willful, and intimidating, presence than ever. Still big and muscular—he’d been a first-string tackle on the football team at Princeton University—Penfield dominated the Neuro in a very real sense. Every week, he convened a staff meeting in a conference room on the third floor to discuss the status of the institute’s patients and research. Dozens of neurosurgeons, neurologists, and electroencephalographers would crowd in, though only the four or five people Penfield considered to be his stars were allowed to sit at the table with him; the rest were relegated to chairs around the periphery of the room. Whenever somebody in attendance said something that displeased him, Penfield would remove his glasses and deliver a hard stare. His subordinates learned to fear that stare in a visceral, Pavlovian way. But for all his occasional bullying, Penfield respected, without prejudice, brilliance. If you stood up to him, and could support yourself with solid facts and arguments, he would back down. And although Brenda Milner, with her sylph-like proportions and gentle, Cambridge-educated accent, was physically unintimidating, her mind quickly revealed razor-sharp claws. Penfield had been hesitant to invite a psychologist into his institute at all—he considered the field wishy-washy and unscientific, dominated by sex-obsessed Freudians—but it wasn’t long after Milner’s arrival that he asked her to join him at the conference table.

  Once there, she would never leave.

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For Milner, the institute felt like home. Her curiosity and inquisitiveness, the qualities that had animated her since childhood, found a place where they could flourish, where the puzzles she confronted were intoxicatingly difficult and the stakes bracingly high. This didn’t mean the day-to-day work situation was idyllic: Penfield allowed Milner access to his patients and provided her with a small office, but for the first several years of her tenure he didn’t pay her a dime and she was forced to “borrow” her notebooks and pencils and other office supplies from the University of Montreal. Even some of the basic psychological tests and manuals that formed the bedrock of her work she had to finagle from generous researchers at other institutions, to whom she pleaded poverty in heartfelt letters, since she couldn’t afford to pay for them herself. In the end, what mattered to her was the work she was able to do. And the work she was able to do was everything she’d ever dreamed of.

  Her basic mandate was to determine whether Penfield’s epilepsy surgeries were having any adverse effects on his patients. She was particularly focused on his psychomotor epilepsy patients, the men and women whose seizures were often characterized by moments of inattention, odd behavior, and short periods of amnesia. By employing his stimulating electrode, Penfield had demonstrated that these specific types of epileptic attacks could be reproduced on the operating table by shocking a part of the brain known as the medial temporal lobes. In addition, the institute’s new electroencephalography equipment, which allowed researchers to monitor the brain’s electrical spikes and discharges in real time noninvasively, without opening the cranium, also indicated that psychomotor seizures often originated in this portion of the brain. So in 1949, Penfield began implementing what to him was the obvious surgical approach to the treatment of these cases: If he could determine that patients’ psychomotor seizures originated in a particular hemisphere, he would open up that side of their skulls and perform a “unilateral partial temporal lobectomy,” removing that hemisphere of their medial temporal lobes. The hemisphere he left behind, Penfield hoped, would pick up the slack for its departed twin. Still, removing brain regions whose function he didn’t understand, even unilaterally, and even if doing so appeared to have a therapeutic benefit, bothered Penfield. That’s why he had asked Donald Hebb to send a psychologist to the Neuro. Brenda Milner’s mission was to determine whether these removals Penfield was making were having an effect on his patients. And, if so, what that effect was.