by Sam Kean
Temporal lobe epilepsy has transformed other people’s lives in a similar way. All human beings seem to have mental circuits that recognize certain things as sacred and predispose us to feeling a little spiritual. It’s just a feature of our brains (Richard Dawkins excepted, perhaps). But temporal lobe seizures seem to hypercharge these circuits, and they often leave victims intensely religious, as if God has personally tapped them as witnesses. Even if victims don’t become religious, their personalities often change in predictable ways. They become preoccupied with morality, often losing their sense of humor entirely. (Laugh lines are few and far between in Dostoyevsky.) They become “sticky” and “adhesive” in conversations, refusing to break them off despite pretty strong signs of boredom from the other party. And for whatever reason, many victims start writing compulsively. They might churn out page after page of doggerel or aphorisms, or even copy out song lyrics or food labels. The ones who visit heaven often chronicle their visions in excruciating detail.
Based on these symptoms, especially the rectitude and sudden spiritual awakening, modern doctors have retrodiagnosed certain religious icons as epileptics, including Saint Paul (the blinding light, the stupor near Damascus), Muhammad (the trips to heaven), and Joan of Arc (the visions, the sense of destiny). Swedenborg also fits the profile. He converted abruptly, he wrote like a methamphetamine addict (one book, Arcana Coelestia, runs to two million words), and he often shuddered and fell down senseless during visions. On occasion he even felt “angels” thrusting his tongue between his teeth as if to make him bite it off, a common danger during seizures.
At the same time there are problems with casting Swedenborg and other religious folk as epileptics. Most seizures last a few seconds or minutes, not the hours that some prophets spend immersed in trances. And because a temporal fit can paralyze the hippocampus, which helps form memories, many temporal lobe epileptics can’t remember their visions in much detail afterward. (Even Dostoyevsky lapsed into vague descriptions when recounting their actual content.) Also, while Swedenborg’s trances in particular blended sights, sounds, and smells into a heady, heavenly froth, most epileptics hallucinate with one sense only. Most damningly, most epileptic auras are tedious, producing the same refulgent light, the same chorus of voices, or the same ambrosial smells time and again.
So while epilepsy might well have induced their visions—the idea makes sense—it’s important to remember that Joan of Arc, Swedenborg, Saint Paul, and others also transcended their epilepsy. Probably no one but Joan would have rallied France, no one but Swedenborg would have imagined angels eating butter. As with any neurological tic, temporal lobe epilepsy doesn’t wipe someone’s mental slate clean. It simply molds and reshapes what’s already there.
Research on electrical activity within the brain, including seizures, has done more than merely shed light on the origins of religious sentiment. It also illuminated one of the eternal debates in the history of neuroscience: whether the brain has specialized parts that control different mental faculties, or whether, like the indivisible soul, the brain cannot be subdivided into smaller units.
Indivisiblists held sway through the middle of the nineteenth century, but the worm started to turn in the 1860s. Paul Broca discovered in 1861 that many people who’d lost the power to speak had lesions in the same part of the frontal lobe. (More on Broca and language later.) Around that same time, English neurologist John Hughlings Jackson noticed that many epileptics had uncannily similar seizures. These weren’t grand mal eruptions or temporal lobe raptures, but mild shaking palsies that started in one spot and “marched” up and down the body in unvarying order. If the big toe started trembling, then the foot, calf, and leg always followed, in that order. If the elbow started quaking, then the forearm, hand, and individual fingers followed. Jackson deduced that the brain must contain a body map with discrete territories, and that seizure hurricanes must be roaming across this map from region to region. This research had a special poignancy for Jackson, because one of the epileptics he studied was his wife, Elizabeth, who died at forty of complications from the disease. Although never a warm man—Jackson rarely bothered to remember patients’ names—Elizabeth’s death devastated him, and he became a semirecluse.
Localization research got another boost in the early 1870s. First, a pair of bearded Berliners, Gustav Fritsch and Eduard Hitzig, began a series of experiments on the brains of anesthetized dogs. They ran most of these experiments in Hitzig’s spare bedroom, strapping the dogs down on Frau Hitzig’s dressing table. By sparking different spots in the brains, the duo managed to flail the dogs’ limbs and twitch their faces. Another scientist one-upped them in 1873: he made cats extend their paws as if playing with twine, made dogs retract their lips as if snarling, even made a rabbit dismount from a table with a backward somersault. Both sets of experiments proved that electricity could excite the brain’s surface, and they provided a crude map of movement and sensation centers.
However tantalizing, this work didn’t impress everyone, mostly because it involved lower animals. No doubt the human brain differed, perhaps significantly. To confirm the existence of specialized brain regions in human beings, then, scientists needed a human test case. She finally emerged in 1874, in Ohio. Her story could have been a triumph of nineteenth-century medicine. Instead it became a prime example of scientific hubris and abuse of power.
After serving in the Union army, an impressively bearded doctor named Roberts Bartholow moved to Cincinnati in 1864. Although considered icy, he attracted flocks of patients, and he soon opened up one of the country’s first “electrotherapeutic rooms” in the Good Samaritan Hospital. The room included a chair for patients to sit in, as well as a few generators: one produced alternating current, and looked like an oversized sewing machine with metal coils around it; the other produced direct current, and looked like a wooden pantry stuffed with fluid-filled mason jars. The electricity from the devices flowed into metal suction cups or slender metal probes, which Bartholow used to treat polyps, cancer, hemorrhoids, paralysis, impotence, and pretty much every other ailment. He even crafted special sponge “slippers” to tingle his patients’ feet.
The experiments on animal brains had enraptured Bartholow, and some historians suspect that as soon as poor Mary Rafferty removed her wig in his office, the forty-two-year-old doctor made up his mind what to do. Rafferty, a feebleminded thirty-year-old Irish maid, had fallen into a fire one morning as a lass and had burned her scalp so badly that the hair never grew back. She wore a wig over her scars, but in December 1872 a malignant ulcer opened up beneath it. Rafferty blamed the ulcer on the wig’s sharp whalebone frame, which dug into her skin; Bartholow diagnosed cancer. Whatever the cause, when Rafferty arrived at Good Samaritan in January 1874, a two-inch hole had opened in her skull, and a wide-eyed Bartholow could see her parietal lobes pulsating.
Doing what they could, the nuns who served as hospital nurses dressed and re-dressed Rafferty’s wound. But she just didn’t get any better, and by March she was clearly dying. Around this time Bartholow sidled up to Rafferty and, oozing charm, asked her about undergoing some tests. In defending himself later, Bartholow recalled that Rafferty had “cheerfully” agreed. Given her feeblemindedness, she likely didn’t grasp what she’d agreed to. Bartholow sat her down in the electrotherapeutic room anyway and unwrapped her turban of bandages. He then slid two needle-shaped electrodes into her gray matter and closed the switch on the sewing-machine generator.
The exposed brain of Mary Rafferty, the subject of one of the most unethical experiments in medical history.
Based on Rafferty’s reaction, Bartholow must have tapped into her motor centers: her legs kicked out, her arms flailed, her neck twisted backward like an owl’s. Bartholow later claimed that she’d smiled during this macabre dance, but given that she also shrieked throughout, her facial muscles had probably just twisted into a rigid mockery of mirth. (The brain’s surface cannot feel pain, but its lower regions can; sparking the brain can a
lso cause pain in the body.) Because she kept smiling Bartholow pushed on, moving the electrified needles around and increasing the current for “a more decided reaction.” He got it. Her pupils dilated, her lips turned blue, her mouth frothed. She began breathing erratically and soon suffered a seizure, five full minutes of thrashing. Bartholow called it a day at that point, and Rafferty collapsed into bed pale and dizzy. Her pupils were also “blown”—dead and unresponsive. Bartholow nevertheless decided to tase her brain again a few days later, this time using the wooden cabinet generator. Understandably, the sight of the equipment induced a sort of posttraumatic seizure in Rafferty, and she fell unconscious (“stupid and incoherent,” in Bartholow’s words). Bartholow reluctantly postponed his experiments—and Rafferty died before he could resume them. An autopsy found needle tracks an inch deep inside her brain.
When Bartholow blithely published these results, the medical world turned on him like an autoimmune reaction: doctors worldwide howled, and the American Medical Association censured him. Chagrined but defiant, Bartholow countered that Rafferty had given informed consent—she’d said yes. And in spite of all the pious protestations, he argued, he’d proved what he’d set out to: the human brain had specialized regions of function, which scientists could probe with electricity. Having staked his claim as a pioneer, Bartholow did admit that, given the suboptimal outcome (i.e., death), repeating the experiment “would be in the highest degree criminal.” But how could he have known beforehand? This half apology absolved Bartholow in some circles, and his career never really suffered: he built the largest practice in Cincinnati, cofounded the American Neurological Association, and earned honorary degrees in Edinburgh and Paris. But the fiasco probably did retard the study of the living human brain, since other scientists didn’t want the stink of another Mary Rafferty on them.
Although a few scientists (like Harvey Cushing) did probe the living brain with electricity during the next few decades, the work proceeded fitfully, and it took a man of Wilder Penfield’s stature to fully rehabilitate the field. Penfield’s career did not get off to the most promising start, actually: his first two surgical patients died, a common occurrence in the 1920s.* Nevertheless, Penfield honed his techniques and by the end of the 1920s was taking on the most difficult cases of epilepsy out there. Many epileptics had scars or tumors inside their brains, and in those cases the operation was as straightforward as neurosurgery can ever be: just scoop out the offending tissue. Penfield, though, also took on patients without obvious trauma or damage—a much trickier procedure, since it wasn’t clear where the epicenter of the seizure was.
To find the epicenter, Penfield became, essentially, a cartographer. Because so few people had explored a conscious brain before, whole continents of the neural hemispheres remained as sketchy as early-1500s maps of the Americas. So Penfield decided to create a better map, by using electricity as his compass and sextant. The work really got going in 1934, when the institute that he’d vowed to establish after Ruth’s death finally opened in Montreal, a $1.2 million affair (roughly $21 million today) nicknamed the Neuro. The Neuro attracted scores of brilliant scientists—David Hubel of the cat-vision experiments got his start there—but it was Penfield’s mapping work that proved the most influential.
At least superficially this work resembled Roberts Bartholow’s experiments on Mary Rafferty, in that Penfield was using electrified wires to spark the brain’s surface. Penfield, however, used lower and more precise voltages. And rather than treat the patient as a passive tool—zapping her brain and seeing what the hell happened—Penfield collaborated with each patient, gently stimulating various spots on her cortex and asking what she felt at each point.
Often she felt nothing. But when she did experience something, Penfield dropped a marker—a numbered piece of confetti—onto that square millimeter of tissue, and a secretary behind a glass wall recorded the result. The kinds of reactions varied geographically around the brain. If Penfield stimulated the visual cortex (in the back), the patient might see lines, shadows, or crosses—the constituent elements of sight. If he stimulated the auditory cortex (above the ears) she might hear ringing, hissing, or thumping. If he stimulated the movement and tactile centers she might begin swallowing violently or comment, “Mah thongue theems tah be pallalyzed.” More provocatively, stimulating the speech centers often forced the patient to sing against her will—an aria of aaaaah that got louder every second. Penfield did have a sense of mischief and sometimes got patients talking only to cut them off: “I visited my daughter yesterd-aaaaah—” He challenged another man to keep quiet no matter what—to try as hard as he could not to say anything. The patient bit down, and Penfield even warned him when the zap was coming. It didn’t matter: the man sang like a canary. “I win,” Penfield said. The man laughed.
These neurological soundings improved brain surgery in two ways. First, Penfield often succeeded in triggering a patient’s aura at some point. This wasn’t always a pleasant process, since the auras might include nausea, dizziness, or foul smells. But when he’d zeroed in on that sensation, he knew what folds of tissue to remove in order to interrupt the seizure circuit. Second, and just as important, Penfield knew what not to remove. He always began his surgeries by mapping out the boundaries of the patient’s movement and speech centers. He could then steer clear of those centers when excavating tissue.
Determining what areas to avoid had an unexpected side benefit, in that it allowed him to map the brain’s movement and tactile centers in unprecedented detail. No one before Penfield knew that the face region lies next to the hand region, or that the face, lips, and hands all owned huge, Canada-sized territories. These discoveries laid the groundwork for understanding phantom limbs in later decades. In a broader sense they also demonstrated just how unusual the brain’s view of the body is. To drive that point home, Penfield sketched a famous cartoon, the “cortical homunculus,” in the 1950s, a vision of what human beings would look like if the size of each body part corresponded to the amount of cortical territory devoted to running it. Turns out we’d all have Q-tip legs, bee-stung lips, and huge mitts for hands—within our brains we all look like bad Giacomettis.
A sensory homunculus, after Wilder Penfield. The sensory homunculus and motor homunculus (not shown) are representations of what the body would look like if the size of each body part was proportional to the amount of gray matter dedicated to running it.
Penfield found evidence of brain rewiring as well. In truth, the atlas Penfield developed for the human brain was idealized—a platonic form that no individual brain conformed to. A language node in Adam, for instance, might sit several centimeters higher or lower than in Bob. And even within Adam, the language node might shift around year by year as his brain rewired itself, something Penfield noticed when he had to operate several times. Contrary to most scientists’ expectations, then, each brain, each mind, had a unique geography. And its geography changed over time, since brain territories drifted like continental plates.
Of all the things Penfield uncovered about the brain, he cherished one discovery above all. It involved the temporal lobes, and he cherished it because it rose above the grubby, animalistic realms of touch and movement and sight, and soared toward the human soul. Neuroscientists had long neglected the temporal lobes, so when Penfield zapped the temporal lobe of a female patient in 1931 he had low hopes of finding anything good there. Instead of a typical sensation, though—a vague buzz, a patch of green light—her mind was transported back to the birth of her daughter twenty years before, an unusually crisp and specific vision. Penfield, bemused, never followed up on this. (He remembered thinking at the time, “It was never intended that men should understand [women] completely.”) But five years later he provoked a similarly sharp memory in a teenage girl’s temporal lobe. She was transported to an idyllic afternoon during her childhood, which she’d spent frolicking with her brothers in a field. Unfortunately a pervert had ruined everything by sneaking up behind her with a writhi
ng burlap sack and asking, “How would you like to get into this bag with the snakes?” This memory happened to be the girl’s seizure aura, so Penfield knew he had to excise this tissue. But this time Penfield took careful notes first, and afterward decided to investigate the temporal lobe further.
In fact, although he kept this work somewhat secret, Penfield spent the next two decades investigating as many temporal lobe visions as possible. Some people’s visions proved mundane. One man saw a 7UP billboard. One woman pictured her dipsomaniac neighbor, Mr. Meerburger. Another woman heard an orchestra fading in and out every time Penfield lowered and raised his electrified wire, as if he were dropping a needle on a gramophone. (The woman in fact accused Penfield of hiding a phonograph in the operating theater.) Other visions, though, were more profound. People saw glimpses of heaven or heard angelic choruses—the sorts of auras that turn people toward religion. Several people saw their lives flash before their eyes, and one man hollered, “Oh, oh, God—I’m leaving my body!” and found himself hovering above his own operation.
At first, overly excited, Penfield thought he’d found the seat of human consciousness in the temporal lobes. He later revised that opinion and situated consciousness deeper down, somewhere near the brainstem. (This would explain why patients never lost consciousness during operations, even when surgeons were scooping out whole handfuls of upper brain. Later, however, we’ll see why Penfield was wrong in his assumptions and why it makes little sense to search for a single locus of consciousness at all.) Regardless, Penfield maintained that working with the temporal lobes at least provided access to people’s consciousnesses—a way to tap into their inner essences, perhaps even their innermost souls.