Permanent Present Tense

by Suzanne Corkin

  A popular way to think about memory in the brain is to borrow a metaphor from computer science: memory is information that the brain processes and stores. To succeed in this undertaking, the brain needs to perform three steps: it must encode the information, turning the raw data of experience into a brain-compatible format; it must store the information for later use; and it must be able to retrieve the information from storage later.

  At the time of Henry’s operation, little was known about how these memory processes work in the brain. In the 1960s, the discipline we now call neuroscience barely existed. Since then, Henry’s case has been essential to a series of profound scientific discoveries on the nature of memory and the specific processes by which it is achieved. One basic yet crucial lesson that Henry taught us was that it is possible to lose the ability to remember, yet remain intelligent, articulate, and perceptive. It is possible to forget a conversation that took place minutes before but still have the ability to solve challenging crossword puzzles.

  The kind of long-term memory Henry lacked is now called declarative, because people can state openly what they learned. By contrast, Henry did possess long-term memory for motor skills, such as how to use a walker; this sort of memory is now termed nondeclarative because people demonstrate their knowledge through performance and cannot verbalize what they learned.5

  As neuroscience and particularly the science of memory evolved in the latter half of the twentieth century, Henry’s case remained deeply relevant to research. As new theories about memory processes and new brain-imaging tools emerged, we applied them to his case. Until his death in 2008, he patiently allowed me, and more than a hundred other scientists, to study him, greatly advancing our knowledge of how the brain remembers—or fails to remember.

  Because Henry donated his brain to the Massachusetts General Hospital (Mass General) and MIT in 1992, he continues to play a role in new frontiers of science. The night he died, we scanned his brain in an MRI machine for nine hours. Later his brain was preserved, and then embedded in gelatin, frozen, and cut into 2,401 ultrathin slices from front to back. These slices have been digitized and assembled into a three-dimensional image that scientists and the public will eventually be able to view on the web, offering a new way to explore in detail the anatomy of a single, well-studied amnesic brain.

  We have few examples of individual patients who completely transformed a scientific field as Henry did. His story is not just a medical curiosity; it is a testament to the impact that a single subject can have. Henry’s case answered more questions about memory than the entire previous century of scientific research. Although he lived his own life in the present tense, Henry had a permanent impact on the science of memory, and on the thousands of patients who have benefited from his contributions.

  One

  Prelude to Tragedy

  In June 1939, the Molaison family was living in Hartford, Connecticut. Just across the Bulkeley Bridge was East Hartford, a city buzzing with the thrill of aviation, since it was home to Pratt & Whitney, a world leader in the manufacture of airplane engines. Pilots offered the public “sky rides” in small planes and thirteen-year-old Henry had excitedly watched these flights from the ground. He was finally going to experience one firsthand, his junior-high graduation present.

  Henry and his parents drove to Brainard Field, tucked against the Connecticut River three miles southeast of downtown Hartford. There, Gus Molaison paid $2.50 for Henry to take a short tour over the city in a single-engine Ryan airplane, similar to the Spirit of St. Louis that Charles Lindbergh had flown across the Atlantic twelve years before—seated alone in a wicker chair, with the barest emergency supplies to sustain him and only a 223-horsepower engine to keep him from plunging into the empty sea. The Ryan’s surface was polished aluminum and the interior of the cabin was lined in matte green leather. Henry settled into the copilot’s seat on the right side of the plane, and the pilot showed him the controls—the yoke that guided turns and made the plane climb or descend, and the foot pedals that directed the plane’s rudder.

  As the engine started, the propeller began spinning and soon seemed to disappear. The pilot pushed the throttle forward, and before long the plane lifted off the runway and soared over the airport. On that spring day, everything on the ground was green and vibrant. The pilot steered them over the city of Hartford, and Henry could see the tops of the downtown buildings—Hartford’s tallest building, the Travelers Tower, and the Old State House with its gleaming gold dome.

  The plane was outfitted with two sets of controls, and the pilot let Henry steer. He grasped the yoke, which could be moved forward and back to point the nose up or down, or rotated to turn the plane to either side. The pilot cautioned him to hold the yoke steady and never push it forward abruptly, which would angle the plane’s nose down and cause it to dive. Henry was surprised by how well he did—the plane soared smoothly under his grip.

  When it was time to land, the pilot took over but allowed Henry to keep his hand on the yoke, which was mechanically linked to the pilot’s. He instructed Henry on how to plant his feet on the floor during the landing to avoid inadvertently touching the rudder pedal that could cause the plane to veer. They descended, heading toward a slight bend in the river where the airport lay. As they began landing, the pilot told Henry to keep the yoke back so that the front would not point too low, causing the plane to “nose over” and land upside down. They touched down delicately and cruised to a stop on the runway.

  For young Henry, that short ride must have stirred the same feelings of adventure and possibility he had felt on hearing of Charles Lindbergh’s improbable journey across the Atlantic. Henry’s plane ride was one of the most exciting moments of his life. Throughout the experience, he was completely entranced by the sensations of the plane, the sight of the world from high above, and the thrill of gripping the controls. Every detail of the ride was vividly recorded in his mind.

  Years later, after Henry had lost his ability to form new memories, all he had left was his past—the knowledge he had acquired up to the time of his operation. He remembered his mother and father, his school friends, the houses in which he had lived, and the vacations his family had taken. But when asked to talk about these memories, he was unable to describe a unique event, a single moment in time with all the sights, sounds, and smells that came with it. He retained the general picture of his experiences but without any specific details.

  Henry’s first and only plane ride was one of two exceptions. Even as an old man, he could still recall the plane’s green interior, the movements of the yoke, the sight of the Travelers Tower, and the pilot’s instructions as he held the plane in his grip—all with perfect clarity. In decades of questioning and interviewing Henry after his operation, this was the only lengthy episode of his life that he ever described in vivid detail. The other exception was the time, at the age of ten, when he smoked his first cigarette.

  Henry was born on February 26, 1926, in Manchester, Connecticut, a town about ten miles east of Hartford, in the Manchester Memorial Hospital. Henry was an eight-pound, full-term, healthy baby. His parents brought him home to their house less than a mile away on Hollister Street.

  Henry’s father, Gustave Henry Molaison, known as Gus, came from Thibodaux, Louisiana. After Henry’s operation, he could recall his father’s family origins, and would joke, “My daddy’s family came from the South and moved north, and my mother’s family came from the North and moved south.” A relative traced the Molaison lineage back to Limoges, France. In the 1600s, the French Cajun people moved to Nova Scotia only to be deported back to France in the mid 1700s. In the late 1700s, they migrated again, this time to Louisiana, and the Molaisons settled in Thibodaux, a small community about sixty miles southwest of New Orleans. Henry’s mother, Elizabeth McEvitt Molaison, known as Lizzie, was born in Manchester, Connecticut, but her parents came from Northern Ireland, where they continued to keep close family ties.

  Gus was tall and lean with dark brown hair, a
n attractive man despite protruding ears. Lizzie was a head shorter than Gus, had curly brown hair, and wore glasses. A distant relative remembers her as having “a very mild temperament and always wearing a smile.” Gus was more gregarious, often laughing and joking with friends. Gus and Lizzie were married in 1917 at Saint Peter’s Church in Hartford; he was twenty-four and she was twenty-eight. The United States declared war on Germany that year, but Gus never served in the military. He worked instead as an electrician in the Hartford area, wiring buildings like G. Fox and Company, a landmark department store on Hartford’s Main Street. Lizzie stayed home like most wives of the time and learned to cook Gus’s familiar southern dishes. But their lives were not totally conventional. Gus and Lizzie were adventurers; they liked to take excursions, driving to Florida, Mississippi, and Louisiana to see relatives, bringing an army-surplus tent to sleep in along the way. Lizzie collected photos and mementos from these trips.

  Lizzie was thirty-seven when Henry was born; he was their only child. They raised him as a Catholic. He attended a private kindergarten in nearby East Hartford and then Lincoln Elementary School in Manchester for first and second grades. By 1931, the Molaisons moved to a single-family house with a yard on Greenlawn Street in East Hartford, the first of several moves around the Hartford area that the family would make during Henry’s youth. That June, Henry and his mother traveled to Buffalo, New York, for a short vacation. On a postcard to Gus, Lizzie wrote, “All well and enjoying ourselves. From . . . ” and Henry, age five, scrawled his name underneath in pencil.

  During the 1930s, the Molaison family lived in a residential neighborhood adjacent to the downtown Hartford area. Henry attended Saint Peter’s Elementary School, next to the church where his parents had been married. He made friends, learned to roller skate, and took banjo lessons at Drago Music House on Main Street. In 1939, Henry, age thirteen, graduated from Saint Peter’s and moved on to Burr Junior High School on Wethersfield Avenue. By this time, his life had begun to change.

  Henry’s childhood was indistinguishable from those of many middle-class boys in the 1930s. Like most boys, Henry occasionally got into accidents, and at some point he sustained a minor head injury in a bicycle mishap. The notes from medical and family sources are contradictory regarding the details: it is not clear exactly how old he was when it happened, whether he fell off his own bicycle or was struck by a cyclist while on foot, or if he lost consciousness as a result. Importantly, we have no evidence that the accident caused any brain damage, and two pneumo-encephalograms (brain X-rays) carried out in 1946 and 1953, before his operation, were normal.

  Yet, when Henry began having epileptic seizures at age ten, his mother would think back to the bike accident and wonder if it had caused some grave but unseen injury to his brain. Perhaps it did, but Gus’s side of the family had a history of epilepsy; two cousins and a niece were epileptic, and Lizzie recalled seeing one of them, a six-year-old girl, lying stiff and inanimate in the grass at a family gathering. Lizzie later labeled this incident a “spell.” She always blamed her husband’s side of the family for Henry’s condition. From a researcher’s point of view, the cause of Henry’s epilepsy could have been his minor head injury, his genetic predisposition, or both.

  At first, Henry’s were petit mal seizures, also called absence seizures. Far from the dramatic convulsions that many people associate with epilepsy, when one of Henry’s spells came on, he simply became mentally absent for a few seconds. He did not shake, fall down, or lose consciousness; he just tuned out for a moment. If he was carrying on a conversation, he would stop talking and appear to be daydreaming. An observer might see him sway, bend his head, and begin to breathe heavily; he often made small, repetitive scratching movements with his fingers over his arms or clothing. When the seizure was over, it was as if he was waking up; he would shake his head and mutter, “I gotta come out of this again.” Sometimes he might be a little dazed, but often he would resume whatever he had been doing as if nothing had happened, although he was aware of having had a seizure. These attacks occurred daily, and Henry would often explain to onlookers that he had just had a seizure.

  Although Henry’s petit mal seizures persisted, they never lasted more than ninety seconds, so they did not prevent him from leading a normal life. He went on vacations with his parents and played with friends in Colt Park, a playground in his neighborhood with tennis courts, baseball fields, and a skating rink. Nor did the seizures disrupt his education in either elementary school or junior high. He went to Sunday mass and studied the Catechism in preparation for his Confirmation in the Catholic Church. Notably, his seizures did not prevent him from taking the controls of the plane during his sky ride when he was thirteen.

  But a drastic change occurred on his fifteenth birthday. Henry was riding in the family car, his father driving and his mother in the backseat. They were heading back to Manchester after visiting some relatives in South Coventry, a historic village about twelve miles away. Before they reached the house, Henry had a seizure unlike any he had experienced before. His muscles contracted, he completely lost consciousness, and his body shook with convulsions. His parents drove him directly to Manchester Memorial Hospital—the hospital where he was born. Afterward, he had no recollection of this episode.

  This was Henry’s first grand mal seizure, also called a tonic-clonic seizure after the two physical processes that occur in succession in the body—a stiffening of the limbs followed by rhythmic convulsions. Unlike the brief absences Henry had experienced before, grand mal seizures can be frightening to witnesses and exhausting for the person experiencing them. He would lose consciousness, bite his tongue, and occasionally urinate, hit his head, and foam at the mouth. These more violent seizures occurred in addition to the frequently occurring petit mal seizures and posed a serious problem for Henry and his family.

  Epilepsy and epileptic have the same word origin as the Greek verb ēpilambánein, meaning to seize or attack. Epilepsy is a disease with a long history, probably dating back to prehistoric man. The first recorded episodes date from the Mesopotamian civilization in the Middle East. A manuscript from the Akkadian Empire (2334–2154 BC) describes an epileptic attack in which the afflicted turned his head to the left, stiffened his hands and feet, frothed at the mouth, and fell unconscious. Centuries of debate pitted physicians, who believed that the cause was physical and should be treated with rational manipulations, such as diet and drugs, against magicians, wizards, and quacks, who contended that epilepsy was caused by supernatural powers and must be cured with purifications and incantations aimed at appeasing the offended entity.1

  The medical understanding of epilepsy moved forward during the sixteenth and seventeenth centuries, when scholars began to focus on the assortment of factors that preceded epileptic attacks, such as sudden fear, excitement, stress, and head injury. This shift toward a scientific interpretation of epilepsy continued during the Enlightenment, when scholars stressed observation of epileptic patients, and experimented on both animals and humans in an effort to uncover the biological causes of epileptic attacks.2

  The nineteenth century witnessed a major advance in the study of epilepsy, as medics began to draw a distinction between epileptic patients and those considered “insane.” In France, clinicians introduced the terms grand mal, petit mal, and absence seizures, and provided a detailed clinical description of each, while psychiatrists became interested in patients’ behavioral abnormalities, including memory disorders.

  In the late nineteenth century, the work of John Hughlings Jackson, the father of British neurology, transformed the study of epilepsy. Jackson compiled the histories of numerous cases, including his own patients, those cared for by his colleagues, and reports in the medical literature. He extracted minute details from these medical records and, based on that rich information, proposed the novel idea that seizures start in a single brain area and progress in an orderly way to other areas. This striking seizure pattern came to be known as Jacksonian epilepsy, and
the initial forays into surgical treatment focused on patients whose abnormality was confined to one discrete brain area.3

  At Jackson’s suggestion, the pioneering London neurosurgeon Victor Horsley performed the first surgery for epilepsy in three patients, publishing two cases in 1886 and the third in 1909. All three patients experienced attacks in which one arm would suddenly jerk violently. During the operations, Horsley stimulated the patient’s exposed brain to identify the area where the affected arm was represented. He then removed that area to arrest the spasms. In 1909, Fedor Krause, a German neurosurgeon, authored a more detailed description of epilepsy surgery. A critical part of Krause’s operative strategy was his focus on stimulating the cortex electrically to map out motor, sensory, and speech areas in the human brain. These pioneering successes provided the initial validation of Jackson’s insight that focal epilepsy was caused by an area of cortical irritation, and suggested that surgical treatment was safe and effective.4

  In 1908, in the United States, Harvey Cushing at the Johns Hopkins Hospital conducted cortical localization studies in more than fifty operations for epilepsy, greatly advancing knowledge on where different functions are located in the human brain. These stimulation studies allowed surgeons to link specific behavioral abnormalities in their patients to specific areas in the cortex, an important prerequisite for epilepsy surgery. The quest to localize specific motor, sensory, and cognitive processes to identifiable brain circuits continues today in thousands of laboratories.