What is *The Tale of the Dueling Neurosurgeons* about?

*The Tale of the Dueling Neurosurgeons* explores the history of neuroscience through gripping stories of brain injuries, illnesses, and recoveries. Sam Kean connects historical cases—like King Henri II’s fatal jousting injury and Phineas Gage’s personality-altering railroad accident—to breakthroughs in understanding brain functions, memory, and behavior. Each chapter uses real-life tragedies to explain how scientists unraveled the brain’s mysteries.

Who should read *The Tale of the Dueling Neurosurgeons*?

This book is ideal for readers interested in neuroscience, medical history, or compelling human stories. Science enthusiasts, psychology students, and fans of narrative non-fiction will appreciate Kean’s blend of vivid storytelling and clear explanations of complex brain functions. It’s accessible to general audiences but detailed enough for those familiar with the subject.

Is *The Tale of the Dueling Neurosurgeons* worth reading?

Yes—Kean’s engaging storytelling and deep research make it a standout. The book translates intricate neuroscience into relatable tales, balancing scientific rigor with historical drama. It’s been praised for its readability and earned accolades like a PEN/E.O. Wilson Literary Science Writing Award nomination.

What are the main concepts in *The Tale of the Dueling Neurosurgeons*?

Key themes include neuroplasticity, memory mechanisms, and how trauma reveals brain functions. Kean examines cases like H.M., an amnesiac patient who transformed memory science, and soldiers with beriberi whose observations advanced neurology. The book also highlights early surgical pioneers like Vesalius and Paré.

How does Sam Kean approach scientific storytelling in this book?

Kean combines historical narratives with clear scientific explanations, using unusual cases—such as phantom limb syndrome and split-brain experiments—to illustrate complex ideas. His playful tone and chapter-opening rebus puzzles make the content accessible without oversimplifying.

What role does Phineas Gage play in the book?

Gage’s infamous 1848 railroad accident, which altered his personality after a iron rod pierced his skull, is analyzed as a pivotal case in understanding the frontal lobe’s role in decision-making and social behavior. Kean contextualizes Gage’s story within broader 19th-century neurological discoveries.

How does *The Tale of the Dueling Neurosurgeons* compare to Kean’s other works?

Like *The Disappearing Spoon* (on chemistry) and *The Violinist’s Thumb* (on genetics), this book uses storytelling to demystify science. However, it focuses exclusively on neuroscience, offering deeper dives into historical medical ethics and brain trauma’s role in scientific progress.

What ethical questions does the book raise?

Kean discusses controversial practices, such as 20th-century lobotomies and unauthorized organ removal from corpses. These examples highlight tensions between scientific curiosity and moral boundaries, emphasizing how past abuses shaped modern research standards.

意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語

トラウマ、狂気、そして回復の真実の物語が明かす、人類の脳の歴史

サム・キーン

4.25(13523 Reviews)

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の概要

脳損傷が神経科学の偉大な発見を解き明かす、奇妙な世界へと飛び込みましょう。アンリ2世の致命的な騎馬試合の事故から、恐怖を感じない患者まで、サム・キーンの語り口は医学の謎を、人類の最も複雑な器官をめぐるスリリングな旅へと変貌させます。科学者も読者も、等しく驚嘆することでしょう。

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1冊の本。さまざまな聴き方。

意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語の同じアイデアを、あなたに合う声・深さ・ペースで学べます。いつでも切り替えられます。

第1章

When Brains Go Awry: A Journey Through the Mysteries of the Mind

The Tale of the Dueling Neurosurgeons sits comfortably among Bill Gates' favorite science books, praised for its ability to make complex neuroscience accessible without sacrificing depth. Sam Kean's masterpiece has developed something of a cult following among medical students and neuroscience enthusiasts since its 2014 publication, with readers often describing it as the book that sparked their fascination with the brain. What makes this work so compelling is Kean's ability to weave historical drama with cutting-edge science-showing us that sometimes the most profound insights about our minds come from studying what happens when things go catastrophically wrong. From kings to cannibals, assassins to amnesiacs, these tales of neurological misfortune reveal the extraordinary architecture of our ordinary brains. What if you couldn't recognize your spouse's face? What if you felt phantom sensations in limbs you no longer possessed? What if you were convinced you were dead despite being able to discuss the matter? These aren't hypothetical questions-they're windows into the brain's inner workings that continue to shape our understanding of what makes us human.

第2章

Royal Trauma and the Birth of Modern Neuroscience

In 1559, King Henri II of France participated in a jousting tournament despite his wife Catherine's prophetic nightmares warning of disaster. When his opponent's lance shattered against his helmet, a wooden splinter pierced the gap in his visor, striking his eye and penetrating his brain. The king's injury would become a landmark case in medical history, foreshadowing nearly every important theme in the next four centuries of neuroscience. As Henri lay suffering, political intrigue immediately surfaced. Catherine seized control, barring Henri's mistress Diane from visiting and ordering criminal decapitations to provide specimens for experimental treatments. Two renowned surgeons attended him: the king's personal physician Ambroise Pare and Andreas Vesalius, summoned from Spain. Vesalius had revolutionized anatomy through his obsessive human dissections and masterpiece "De Humani Corporis Fabrica," which corrected Galen's 1300-year-old errors based on animal studies. While court physicians rejoiced at finding no skull fracture, both Vesalius and Pare recognized the severity of Henri's contrecoup concussion-where the brain slams against the opposite side of the skull from the impact point. Despite their efforts, Henri's condition deteriorated as his brain swelled with inflammation and fluid pressure. He suffered seizures, temporary paralysis affecting only half his body at a time, and vision problems-symptoms that would later inform centuries of neuroscience discoveries. After Henri died on July 10, Vesalius and Pare performed a royal autopsy, discovering pools of blackened fluid and putrefied brain tissue in the rear of Henri's skull-confirming their contrecoup theory and proving that brain trauma alone could be deadly without skull fracture, a revolutionary medical insight. The aftermath proved devastating for France. Catherine, though heartbroken, assumed power as regent when their son Francois II died just seventeen months later. She eventually orchestrated the St. Bartholomew's Day Massacre against Protestants in 1572, claiming thousands of lives-including eventually Gabriel Montgomery, the jouster who had accidentally struck Henri. The medical pioneers who attended Henri followed different paths. Pare thrived despite religious tensions, writing influential texts on head wounds that built upon Henri's autopsy findings. Vesalius, however, left Spain after growing disgusted with superstitious medical practices there. He arranged to reclaim his professorship in Padua but died tragically during his return journey from a pilgrimage to Jerusalem. Henri's death ultimately advanced neuroscience by confirming contrecoup injuries and demonstrating that brain trauma could be fatal even without skull fracture-lessons still relevant today with sports concussions. More importantly, the royal autopsy helped inaugurate a new scientific approach to brain study based on observation rather than ancient theories, setting the stage for centuries of discoveries to come.

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『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の一語一語が音声に合わせてリアルタイムでハイライトされ、自然に読み進められます。

第3章

Cells, Circuits, and Presidential Assassinations

In 1881, Charles Guiteau assassinated President James Garfield, shooting him twice at a Washington train station. Though Garfield initially survived, he endured 80 days of incompetent medical care under Dr. Doctor Bliss, who repeatedly probed his wound with unwashed fingers seeking the bullet. Despite Bliss's "fraudulently optimistic" bulletins, Garfield lost 80 pounds and died after his wound became infected. At trial, Guiteau's insanity defense failed despite his bizarre courtroom behavior-chanting verse, singing, insulting jurors, and comparing himself to historical figures. Only neurologist Edward Charles Spitzka testified convincingly about Guiteau's insanity, noting his lopsided smile, lazy eye, and other neurological symptoms. After conviction, Guiteau was hanged in 1882, reciting his own poem on the scaffold. The autopsy revealed Guiteau's brain appeared normal macroscopically, but microscopic examination showed severe damage-thinned gray matter, dead neurons leaving holes, and yellow-brown residue from dying blood vessels. This case highlighted how brain damage might only be visible microscopically, challenging contemporary understanding of insanity's physical manifestations. Twenty years later, another presidential assassination would advance neuroscience further. After anarchist Leon Czolgosz shot President William McKinley in 1901, Edward Anthony Spitzka performed the autopsy but found no obvious brain abnormalities. However, Spitzka's final report contained a crucial insight: some mental disorders might result from "circulatory and chemical disturbances" rather than visible anatomical defects. This chemical perspective proved prescient. Between these two assassinations, Santiago Ramon y Cajal had established that neurons were discrete cells separated by tiny gaps called synapses. How neurons communicated across these gaps-via chemicals ("soups") or electricity ("sparks")-became the next great neuroscience debate. The debate was settled in 1920 when Otto Loewi conducted his famous dream-inspired experiment with frog hearts, proving that nerves release chemicals to transmit signals. Eventually, scientists discovered over a hundred different neurotransmitters in the brain, revealing a complex system where electrical signals travel down axons but chemical messengers cross synapses. In retrospect, Guiteau likely suffered from schizophrenia compounded by neurosyphilis, while Czolgosz presents a more complex case. Though officially declared sane, Czolgosz underwent a personality transformation after his 1898 mental breakdown, becoming isolated and paranoid. His loneliness and sense of helplessness likely altered his brain chemistry-precisely the "chemical disturbances" Spitzka had intuited in 1901, remarkably foreshadowing our modern understanding of how chronic stress can physically reshape neural connections.

第4章

The Remarkable World of Sensory Rewiring

Lieutenant James Holman became history's most prolific blind explorer despite losing his sight at twenty-five due to extreme temperature shifts during naval service. Though appointed as a Naval Knight of Windsor (a position prohibiting extended travel), Holman's health deteriorated so severely in confinement that doctors convinced the wardens to grant him travel leaves, which immediately improved his condition. Despite his accomplishments, Holman faced constant skepticism. Critics questioned how a blind man could meaningfully travel, while society generally relegated the blind to begging or carnival performances. Holman countered that foreign lands offered distinctive sounds, smells, weather patterns, and daily rhythms that he could perceive perfectly well. He even argued his blindness made him a superior traveler by forcing him to engage with locals rather than relying on superficial visual impressions. To navigate, Holman employed practical adaptations: using coins instead of paper money, a special tactile pocket watch, and a Noctograph dictation machine. Most crucially, he mastered echolocation by clicking his metal-tipped cane and interpreting the sound waves that bounced back from nearby objects. Modern neuroscience explains Holman's abilities through brain plasticity-the brain's capacity to rewire itself. When visual cortex neurons lose their normal inputs, they don't simply die off; they repurpose themselves for other sensory processing. Brain scans of blind echolocators like Daniel Kish (who lost both eyes to cancer as a baby) show strong activity in the visual cortex while processing sound information-their brains have rewired to translate sound into spatial maps. This neural flexibility extends beyond blindness. Paul Bach-y-Rita developed "vision substitution" devices that transformed visual information into tactile sensations. Blind patients using cameras that transmitted images to electrodes on their tongues could identify shapes, navigate obstacle courses, and even experience optical illusions. Brain scans revealed they processed these tongue sensations in their visual cortex-neurologically indistinguishable from actual sight. Bach-y-Rita's interest in brain plasticity began after his father recovered from a devastating stroke through intensive rehabilitation designed by Bach-y-Rita's brother. Despite doctors' pessimistic prognosis, his father relearned to walk, talk, and eventually resumed teaching and hiking-proving the brain could reroute signals around damaged tissue. These breakthroughs suggest our brains can swap one sense for another regardless of input method. All sensory input ultimately becomes chemical and electrical signals-it's our neural circuits, not sensory equipment, that create perceptions. As Bach-y-Rita said, "We don't see with the eyes, we don't hear with the ears. All of that goes on in the brain."

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』をもっと深く楽しむ

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第5章

The Complex Machinery of Vision

During World War I, American sculptor Anna Coleman Ladd created prosthetic masks for soldiers whose faces had been devastated by modern warfare. Working in a Paris studio, she meticulously crafted copper and silver masks painted with enamel to match skin tones, complete with mustaches of metal foil that French soldiers could twirl. However, these artistic masks ultimately fell short. They couldn't function like real faces-they didn't chew, smile, or kiss. The features didn't age naturally, the enamel chipped, and electric lighting often exposed the seam between mask and flesh. Understanding these limitations required comprehending how the brain analyzes faces and, more fundamentally, how it sees the world around us. The first major discovery about vision came from war when Russian bullets created precise brain injuries in Japanese soldiers during the 1904 conflict. Ophthalmologist Tatsuji Inouye mapped these soldiers' blind spots to their specific brain damage, discovering that our brains magnify whatever we're looking at by dedicating more neurons to the center of the visual field. In 1958, neuroscientists David Hubel and Torsten Wiesel made the next breakthrough at Johns Hopkins. After weeks of frustration trying to make visual cortex neurons respond to dots, they accidentally discovered these neurons fire in response to lines at specific orientations. Further research revealed neurons are arranged in columns that prefer specific line angles, with these columns organized in hypercolumns that can detect any line orientation within one visual pixel. Building on these discoveries, the "two streams" theory emerged in 1982. After the primary visual cortex processes basic shape and motion, visual data splits into two processing streams. The "how/where" stream flows into the parietal lobes to determine location and movement, eventually connecting to motor centers for physical interaction. The "what" stream flows into the temporal lobes to determine identity by connecting to memories and emotions. Brain damage to different visual processing areas causes distinct impairments. Primary visual cortex damage destroys basic perceptual skills. Damage to the how/where stream creates spatial disorientation and movement perception problems, as with a Swiss woman who experienced life as frozen snapshots after her stroke. What-stream damage prevents object recognition while preserving drawing ability-patients can perfectly copy images they cannot identify. Even more specific deficits exist. Some patients lose the ability to recognize only animals while easily identifying inanimate objects. Others experience the reverse, recognizing living things but not tools or man-made objects. These category-specific deficits reveal evolutionary specialization in the brain-our ancestors developed dedicated neural circuits for recognizing animals, edible plants, and tools, categories critical for survival. Face recognition employs especially sophisticated brainware. The fusiform face area (FFA) near the brain's south pole specializes in holistic face processing-reading faces instantly rather than piecing them together feature by feature. Evidence for specialized face circuitry comes from face-blindness cases where FFA damage prevents face recognition, and from selective sparing cases like C.K., who lost the ability to recognize any inanimate objects but retained exceptional face recognition abilities.

第6章

Phantom Sensations and Body Maps

One of the most fascinating neurological phenomena emerged during the American Civil War, when surgeon Silas Weir Mitchell documented phantom limb sensations in amputees. These ghostly perceptions occur when the brain's internal body map remains intact despite physical amputation. The Civil War produced unprecedented numbers of amputees due to the devastating Minie bullet, which expanded upon firing, hugging the rifle barrel's grooves for accuracy, then deformed upon impact, shredding tissue instead of passing cleanly through. This weapon shattered limbs beyond repair, forcing field surgeons to perform assembly-line amputations, removing limbs in four minutes before moving to the next patient. Mitchell discovered that 95% of amputees experienced phantoms, with upper-body phantoms felt more vividly than lower-body ones, and extremities like hands and feet perceived more acutely than larger limbs. Some phantoms remained paralyzed while others could be "moved" voluntarily. Most significantly, he found that sensations felt immediately before amputation could become "stamped" into the nerves, persisting for years afterward in the phantom. Mitchell identified raised "buttons" on stumps where nerves had been severed. These sensitive areas suggested that the nerves remained active, still signaling the brain. In one remarkable case, he applied electric current to these buttons and temporarily resurrected a patient's long-vanished phantom arm. Mitchell also recognized the brain's role in phantom sensations. Veterans who lost dominant hands decades earlier still used them in dreams. Most tellingly, people who lost limbs in infancy sometimes experienced phantoms despite having no conscious memory of the limb. This led Mitchell to conclude that the brain contains a permanent mental representation of the complete body-a "scaffold" resistant to amputation, where the brain's internal model trumps physical reality. Phantom sensations extend far beyond missing limbs. Dental extractions produce phantom teeth, hysterectomies lead to phantom menstrual cramps, and amputated penises often persist as phantoms, complete with erections. Unlike the typically painful phantom limbs, these phantom penises are usually pleasurable, so realistic that men might still walk awkwardly when aroused. Modern neuroscience explains phantoms through brain plasticity. Both motor and somatosensory cortices contain "body maps" with dedicated territories for each body part. When a hand is amputated, its large brain territory doesn't remain vacant. Adjacent areas, typically the face, colonize this territory through dormant neural circuits. This explains why amputees might feel phantom hand sensations when touching their face-the signals intermingle as brain territories overlap. V.S. Ramachandran revolutionized phantom limb treatment with his simple "mirror box"-a cardboard contraption with a mirror dividing it into two chambers. When amputees placed their intact hand in one chamber while looking at its reflection (appearing as the missing limb), many experienced immediate relief as their frozen phantoms suddenly moved again. This visual feedback tricks the brain by resolving the mismatch between motor commands and sensory feedback, allowing many patients to experience lasting relief as their brain maps reorganize.

聴きながら、すべての言葉を目で追えます

第7章

The Laughing Disease and Infectious Proteins

In the highlands of Papua New Guinea, the Fore people were dying from a mysterious disease called kuru. Victims initially experienced lethargy, headaches and joint pain before developing balance problems. Most distinctively, they laughed-not from joy but reflexively and senselessly. As the disease progressed, victims lost the ability to stand, sit upright, swallow, and control their sphincters. What made kuru particularly puzzling was its pattern of transmission. It primarily affected women and children, rarely adult men. The Fore believed it was caused by sorcery, but when D. Carleton Gajdusek began studying the disease in 1957, he suspected an infectious agent. After extensive field research, Gajdusek determined kuru was killing approximately 200 people annually-proportionally equivalent to 1.5 million U.S. deaths yearly. Autopsies revealed damage primarily to the cerebellum, the wrinkly "mini-brain" near the spinal cord that coordinates movement and balance. Despite clear anatomical damage, kuru's cause remained mysterious. The brains showed no inflammation but contained protein "plaques" similar to Creutzfeldt-Jakob disease. The breakthrough came when Gajdusek injected kuru brain tissue into chimpanzees. After years of monitoring, the chimps developed identical symptoms, and their brains showed the same plaques and spongy holes. This proved that a degenerative brain disease could be contagious-an unprecedented finding. The connection to cannibalism was finally confirmed when anthropologists discovered Fore women had been consuming the brains of deceased tribe members in funeral rituals. This practice provided crucial protein in their protein-scarce environment and was believed to help the deceased's souls enter paradise more quickly. Scientists struggled to understand what exactly caused kuru. These "slow viruses" defied explanation-they crossed the blood-brain barrier, didn't cause inflammation, and survived extreme sterilization methods including heat, chemicals, radiation, and dehydration. Stanley Prusiner proposed they might be rogue proteins rather than living organisms. Despite initial ridicule, Prusiner named these theoretical agents "prions" and isolated one in 1982. Prusiner discovered that normal brain cells naturally produced proteins identical to prions, but in different 3D configurations. The bad prions could convert good ones by mangling their shape, creating clumps that damaged neurons. When these clumps split, they doubled their conversion capacity, creating an exponential chain reaction that left spongy holes in the brain. This explained kuru's origins-around 1900, someone with Creutzfeldt-Jakob disease died in the highlands, and their infected brain was consumed in a funeral feast. The prions survived cooking and digestion, infected others, and created a deadly cycle. With cannibalism ended in the 1950s, kuru cases gradually declined, and by 2005, the disease had claimed its last victim. Since the 1980s, prion research has grown in importance, explaining mad cow disease and showing similarities to protein plaques in Alzheimer's and Parkinson's. Though kuru itself is extinct, its study laid crucial groundwork for understanding neurodegenerative diseases that affect millions worldwide.

第8章

The Emotional Brain and Its Chemical Messengers

Neurosurgeon Harvey Cushing made a memorable impression on his new resident William Sharpe, immediately sending him to retrieve organs from a deceased giant. This incident exemplified Cushing's brilliant but volatile temperament-his family had nicknamed him "Pepper Pot" for his tantrums, yet his rage dissipated as quickly as it appeared. After Yale and Harvard Medical School, Cushing thrived at Johns Hopkins Hospital, where he pioneered techniques that reduced brain surgery mortality from 90% to 10%. His career path changed after failing to detect a pituitary cyst in a fourteen-year-old girl who subsequently died. Rather than avoiding this obscure gland as most surgeons did, Cushing became determined to understand it. Cushing's childhood fascination with circus "freaks" found scientific purpose as he began studying giants, dwarfs, and people with unusual growth disorders. His research revealed the pituitary as a "master gland" producing multiple hormones, explaining why it was linked to seemingly contradictory conditions. He discovered that pituitary tumors in children could cause either gigantism (excessive growth hormone) or dwarfism (insufficient growth hormone), while in adults, hormone imbalances caused different symptoms-sexual regression with hormone deficiency, or acromegaly (thickening bones and bulging eyes) with excess growth hormone. The modern study of emotions began with James Wenceslaus Papez's 1937 paper identifying an "emotion circuit"-later named the limbic system. This system serves as a transition between the brain's upper and lower regions, processing emotional responses through structures like the thalamus, hippocampus, amygdala, and hypothalamus. When you see something frightening, the thalamus filters sensory input, sending data to the hippocampus for memory processing and the amygdala for emotional assessment. The amygdala then signals the hypothalamus, which activates the pituitary gland to release hormones that trigger physical responses. Though Papez overlooked it in his landmark paper, the almond-shaped amygdalae in the temporal lobes are crucial for processing fear. They jump-start the startle reflex, process smell (the only sense bypassing the thalamus), and determine which stimuli deserve attention. When the amygdala malfunctions, people either feel constantly fearful or, as with patient S.M., lose all capacity for fear. After Urbach-Wiethe disease destroyed her amygdalae, S.M. showed no fear response in any situation-handling snakes enthusiastically despite claiming to hate them, poking actors in a haunted house, and even remaining calm when held at knifepoint. The limbic system and temporal lobes are deeply involved in sexual behavior as well. When Heinrich Kluver and colleague Paul Bucy removed monkeys' temporal lobes (including limbic structures), the animals developed bizarre behaviors: they couldn't recognize objects, developed hyperorality (compulsively licking everything), and became hypersexual. Human patients with Kluver-Bucy syndrome similarly display hyperorality, inappropriate sexual behaviors, and pain asymbolia-intellectually recognizing pain without emotional response. The frontal lobes interact with limbic circuits to regulate primal emotions, allowing humans a more nuanced emotional repertoire than other animals. When brain damage releases primitive impulses, profound ethical questions arise about responsibility. The case of a Virginia teacher demonstrates this dilemma-a previously law-abiding man who suddenly developed pedophilic urges when a brain tumor emerged. When surgeons removed the tumor, the urges disappeared; when it regrew, they returned. Such cases raise difficult questions for our legal system, which assumes people who understand right from wrong can control their actions.

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第9章

Consciousness, Memory, and the Divided Brain

Wilder Penfield revolutionized brain mapping at the Montreal Neurological Institute in the mid-20th century. Unlike earlier crude electrical stimulation experiments, Penfield used gentle techniques with conscious patients, stimulating brain spots and asking what they experienced. This approach allowed him to both locate seizure epicenters and map critical brain functions to avoid during surgery. Penfield's mapping revealed unprecedented details about brain organization-that face regions lie next to hand regions, and that faces, lips and hands occupy disproportionately large territories. His famous "cortical homunculus" illustrated how humans would look if body parts matched their brain representation: stick legs, huge lips, and massive hands. Penfield's most treasured discovery came from temporal lobe stimulation, which triggered extraordinarily vivid memories-a woman reliving her daughter's birth, a teenager recalling a childhood trauma. Some patients saw mundane images like billboards, while others experienced profound visions of heaven or out-of-body sensations. Though Penfield initially thought he'd found the seat of consciousness in the temporal lobes, modern neuroscience has since shown that consciousness emerges from the coordinated activity of multiple brain regions. Memory, another crucial aspect of consciousness, reveals itself most clearly when damaged. In 1953, neurosurgeon William Scoville performed a radical operation on patient H.M., removing three inches of hippocampus from each side along with the amygdalae. While the surgery reduced H.M.'s epileptic seizures, it devastated his memory. He lost a decade of memories before the surgery and couldn't form new ones afterward. Neuropsychologist Brenda Milner's studies of H.M. revealed groundbreaking distinctions between memory types. Though H.M. couldn't form declarative memories (facts, names, dates), he could develop procedural memories (unconscious motor skills). When Milner had him trace star patterns while looking in a mirror, he improved over multiple sessions despite having no recollection of previous attempts. This discovery shattered the notion of memory as monolithic, proving different memory systems rely on distinct brain structures. Another famous amnesiac, K.C. from Toronto, lost both hippocampi in a 1981 motorcycle accident. His parahippocampi survived, allowing him to retain semantic memories (factual knowledge) while losing all episodic memories (personal experiences). He could remember the Dewey decimal system from library volunteering without knowing why he knew it. This evidence showed that episodic memories rely on the hippocampus while semantic memories utilize the parahippocampus. The largest structures in the brain are the left and right hemispheres, with human brains showing striking left/right differences, especially regarding language. In 1861, Paul Broca discovered what would become known as Broca's area-a specialized language node in the left frontal lobe-after examining a patient nicknamed "Tan" who could only say "tan tan" despite understanding language perfectly. Later, Karl Wernicke discovered another type of aphasia caused by lesions in the temporal lobe, where patients could speak fluently but produced meaningless "word salad" sentences without realizing it. Roger Sperry's split-brain research in the 1960s revealed profound differences between the hemispheres. When testing patients whose corpus callosum had been severed to treat epilepsy, Sperry discovered that images shown to the right visual field (left brain) could be verbally identified, while those shown to the left field (right brain) were denied verbally yet acknowledged through left-hand movements. The right hemisphere proved superior at recognizing faces and spatial tasks, while the left brain dominated language. Despite these specializations, both hemispheres normally work complementarily-the right brain better determines causal links and faithfully records sensory data, while the left excels at pattern recognition and conceptual leaps.

第10章

The Enduring Mystery of Self

On September 13, 1848, railroad foreman Phineas Gage suffered history's most famous neurological injury when a tamping iron blasted through his skull. After the accident, Gage's personality transformed dramatically-once resolute and courteous, he became capricious, profane, and unable to make sound decisions. He refused reinstatement as foreman and instead worked odd jobs, exhibited himself at P.T. Barnum's museum, and later became a stablehand and coach driver. Despite becoming neuroscience's most famous case, much about Gage remains mysterious. Modern historians have challenged the traditional narrative that he became a drunken drifter, noting that he held responsible jobs after his injury, including seven years driving stagecoaches in Chile-an astonishingly complex job requiring dexterity, quick reactions, memorization of routes, and financial responsibility. Modern neuroscientists view consciousness not as localized in one brain region but as "a process in a population" emerging when multiple brain parts work in harmony. The reticular formation in the brainstem controls sleep-wake cycles and acts as consciousness's power switch. The thalamus serves as an information broker, receiving and relaying signals throughout the brain like a telephone operator. The prefrontal parietal network activates when we pay close attention-another crucial aspect of consciousness. Short-term memory also proves essential, as it allows us to track experiences from moment to moment. English musician Clive Wearing offers a stark contrast to Gage's preserved consciousness. After contracting herpes-induced encephalitis in 1985, Wearing suffered severe limbic system damage that destroyed both his episodic memory and his short-term working memory. Unlike other amnesiacs, Wearing experiences a perpetual sense of "just waking up"-believing every few minutes that he's becoming conscious for the very first time. His diaries reveal this obsession with entries like "8:31 AM: Now I am really, completely awake" followed by "9:06 AM: Now I am perfectly, overwhelmingly awake"-each new entry causing him to strike through previous ones as false. Despite profound memory loss, even the most severely affected amnesiacs retain some core sense of self. Clive Wearing can still sight-read music and play piano through procedural memory, temporarily resurrecting his pre-injury identity. His emotional memories also remain intact, particularly his devotion to his wife Deborah. Each time she visits his nursing home, he erupts with joy as if seeing her for the first time. The persistence of self appears even in more extreme cases like Tatiana and Krista, conjoined twins born in 2006 with fused skulls and a unique "thalamic bridge" connecting their brains. They speak simultaneously, taste what's in each other's mouths, feel each other's pain, and fall asleep in unison-possibly even sharing dreams. Despite this shared consciousness, they maintain distinct personalities-Krista breaks out in hives from canned corn while Tatiana doesn't; Krista loves ketchup while Tatiana hates it. Neurologically, we seem to have a core brain circuit defining the self, weaving together many strands: autobiographical memories, physical appearance, continuity through time, personal agency, and personality traits. Like a tapestry, this self doesn't depend on any single strand-making it remarkably tenacious through life's vicissitudes. Even Phineas Gage, the paradigmatic example of a life destroyed by brain injury, likely recovered more than scientists ever hoped. After his accident, friends claimed Phineas was no longer himself-but in a profound sense, "he was and he wasn't. And he was all of us, too."

★★★★★

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100万人以上の学習者に愛用されています

“23日間、毎日使い続けています。今では日課の一部です。”

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『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の主要テーマ

neurological case studies
medical history mysteries
brain trauma evolution
localization of function
neuroscience pioneers

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の名言

The king's injury would become a landmark case in medical history.
Insanity's physical manifestations.
Some mental disorders might result from 'circulatory and chemical disturbances' rather than visible anatomical defects.
Critics questioned how a blind man could meaningfully travel.

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の登場人物

King Henri IIFrench monarch whose jousting injury is a case
Andreas VesaliusAnatomist who performed the royal autopsy
Ambroise PareKing's physician and pioneer in treating wounds
Charles GuiteauAssassin whose brain was studied for insanity
Edward Charles SpitzkaNeurologist who testified on Guiteau's insanity

著者について

『ニューヨーク・タイムズ』紙のベストセラー、*『デュエリング・ニューロサージャンズ：外傷、狂気、回復の真実の物語が明かす人間の脳の歴史（The Tale of the Dueling Neurosurgeons: The History of the Human Brain as Revealed by True Stories of Trauma, Madness, and Recovery）』*の著者であるサム・キーンは、複雑な科学的概念を魅力的な物語へと昇華させることで高く評価されています。

物理学者としての訓練を受けたサイエンスライターであるキーンは、物理学と英文学のバックグラウンドを融合させ、脳損傷の歴史的事例研究とそこから得られた画期的な知見を通じて神経科学を探求しています。王立協会科学図書賞のファイナリストとなった*『スプーンと元素（The Disappearing Spoon）』や、『ガーディアン』紙のサイエンス・ブック・オブ・ザ・イヤーに選ばれた『カエサルの最後の一呼吸（Caesar’s Last Breath）』*などの著作は、科学、歴史、そしてストーリーテリングを織り交ぜる彼の才能を象徴しています。

キーンの専門知識はNPRの*『Radiolab』や『Science Friday』で紹介されており、彼の記事は『The Atlantic』や『The New Yorker』にも掲載されています。『デュエリング・ニューロサージャンズ』*はPEN/E.O.ウィルソン・リテラリー・サイエンス・ライティング賞にノミネートされ、親しみやすい科学執筆の第一人者としてのキーンの名声を確固たるものにしました。彼の著書は全世界で累計数百万部を売り上げています。

意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語の要約をダウンロード

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Brain

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Do No Harm

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Brain's Way of Healing

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Life Lessons from a Brain Surgeon

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Disordered Mind

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Phantoms in the Brain

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The Brain That Changes Itself

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コロンビア大学卒業生がサンフランシスコで開発

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BeFreedがウェブ上でどのように話題になっているかをもっと見る

コロンビア大学卒業生がサンフランシスコで開発

LOVED BY

1,000,000+ curious minds.

4.7

avg rating

1M+ learners

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."

@Moemenn

"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."

@Chloe, Solo founder, LA

117

"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."

@Raaaaaachelw

"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."

@Matt, YC alum

108

"Reading used to feel like a chore. Now it’s just part of my lifestyle."

@Erin, Investment Banking Associate , NYC

254

"Feels effortless compared to reading. I’ve finished 6 books this month already."

@djmikemoore

"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."

@Pitiful

4.5K

"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."

@SofiaP

"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"

@Jaded_Falcon

201

"It is great for me to learn something from the book without reading it."

@OojasSalunke

"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."

@Leo, Law Student, UPenn

483

"Makes me feel smarter every time before going to work"

@Cashflowbubu

BeFreedがウェブ上でどのように話題になっているかをもっと見る

今すぐ学習の旅を始めよう

第9章

意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語

概要『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の概要

1冊の本。さまざまな聴き方。

When Brains Go Awry: A Journey Through the Mysteries of the Mind

Royal Trauma and the Birth of Modern Neuroscience

聴きながら、すべての言葉を目で追えます

Cells, Circuits, and Presidential Assassinations

The Remarkable World of Sensory Rewiring

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』をもっと深く楽しむ

The Complex Machinery of Vision

Phantom Sensations and Body Maps

聴きながら、すべての言葉を目で追えます

The Laughing Disease and Infectious Proteins

The Emotional Brain and Its Chemical Messengers

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』をもっと深く楽しむ

Consciousness, Memory, and the Divided Brain

The Enduring Mystery of Self

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』を最後まで読み終えました

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の主要テーマ

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の名言

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の登場人物

著者について

意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語の要約をダウンロード

他のユーザーのお気に入り

この本に関するよくある質問

What is The Tale of the Dueling Neurosurgeons about?

Who should read The Tale of the Dueling Neurosurgeons?

Is The Tale of the Dueling Neurosurgeons worth reading?

What are the main concepts in The Tale of the Dueling Neurosurgeons?

もっと見る

1,000,000+ curious minds.

1,000,000+ curious minds.

1冊の本。さまざまな聴き方。

When Brains Go Awry: A Journey Through the Mysteries of the Mind

Royal Trauma and the Birth of Modern Neuroscience

聴きながら、すべての言葉を目で追えます

Cells, Circuits, and Presidential Assassinations

The Remarkable World of Sensory Rewiring

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』をもっと深く楽しむ

The Complex Machinery of Vision

Phantom Sensations and Body Maps

聴きながら、すべての言葉を目で追えます

The Laughing Disease and Infectious Proteins

The Emotional Brain and Its Chemical Messengers

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』をもっと深く楽しむ

Consciousness, Memory, and the Divided Brain

The Enduring Mystery of Self

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』を最後まで読み終えました

他のユーザーのお気に入り

もっと見る

『意識をめぐる4億年の旅：脳の進化から心まで、12の奇妙な物語』の概要