The death watch for Albert Einstein began with his collapse from a ruptured abdominal aortic aneurysm on April 13, 1955. Two days later he was moved from his house at 112 Mercer Street to Princeton Hospital. In the hospital he spoke with his son, Hans Albert, often declined morphine, called for writing materials, and announced, “It is time to go. I will do it elegantly.” On April 18, following a few words in German and two last breaths, Einstein died at age 76. Later that morning, Dr. Thomas Harvey (with Einstein’s executor, Otto Nathan, in attendance) performed the autopsy, which revealed “an abdomen full of blood” from the fatal breach of Einstein’s aorta.1 The brain and other internal organs were removed for gross inspection. The viscera were returned to the body, which was cremated in Trenton. To this day no one knows where Albert Einstein’s ashes lie.
What became of the brain of the man hailed as the “embodiment of pure intellect” and “person of the century” by Time magazine? Harvey, a Yale-trained pathologist who had worked with such neuroscientiﬁc luminaries as Harvey Cushing, John F. Fulton, and Harry Zimmerman, saw a unique opportunity in studying Einstein’s brain. He ﬁlled the carotid arteries with a preservative solution and suspended the brain in the same chemical. The front page of the April 19, 1955, New York Times announced “...the removal, for scientiﬁc study, of...the brain that worked out the theory of relativity and made possible the development of nuclear ﬁssion.” Einstein’s family questioned this decision, but Harvey persuaded them of the critical importance of further study.
Harvey was not alone in his ambition to investigate Einstein’s brain with scientiﬁc rigor. While the brain was being preserved, Harvey was summoned to a conference at the Armed Forces Institute of Pathology in Washington, DC, and was sorely importuned by Dr. Webb Haymaker and other eminences grises of American neuropathology to relinquish the brain. The 43-year-old Princeton pathologist rebuffed their overtures and began to prepare the brain for study. He made exact measurements directly from the brain and took calibrated photographs with his Exakta 35mm camera. Then he carried the brain across the Delaware River to the University of Pennsylvania, where he enlisted the expertise of Marta Keller, the pathology technician of Fritz Lewy, Harvey's deceased mentor and the discoverer of the specific neuropathological changes of Parkinson's disease.
The Berlin-trained Keller cut Einstein’s hemispheres into 240 blocks, which were embedded in celloidin. Directing the dissection, Harvey relied on the neuroanatomical guidelines in Percival Bailey and Gerhardt von Bonin’s The Isocortex of Man. In addition to listing mid-20th century state-of-the-art techniques (tissue blocks permitting sections perpendicular to the cortical surface, Nissl staining of neuronal and glial cell bodies, and Weigert staining of myelinated axons connecting the neurons), Harvey’s dog-eared and underlined copy of this book included a healthy dose of skepticism about previous cerebral “mapmakers... [whose] impossible to check [human studies] have been accepted by physiologists as a divine authority and a vast superstructure has been built on this shaky foundation.”2
Twelve sets of microscope slides were painstakingly indexed to the tissue blocks, and Harvey gave the sets to the best and brightest in neuropathology at the time, including Bailey and von Bonin at the University of Illinois, Walle Nauta at MIT, and Harry Zimmerman at Monteﬁore Hospital. But the potential Rosetta Stone of genius remained undecipherable to these savants, and Harvey received no report of neuropathological ﬁndings beyond Zimmerman’s assurance that Einstein’s brain was normal for his age.
At this point, we may well ask Harvey’s own professional opinion of Einstein’s brain. Einstein’s hospital record and autopsy report vanished without a trace, just as his last utterances in German were lost on his English-speaking night nurse. But 55 years after the autopsy, Harvey recalls ﬁnding a few “plaques and neuroﬁbrillary tangles” in Einstein’s brain. (In great abundance these ﬁndings indicate Alzheimer’s disease, but in lesser quantities are consistent with normal “successful” aging). Harvey’s examination did not ﬁnd signs of Parkinson’s disease or dementia. Harvey concluded that Einstein’s brain fell “within normal limits for a man his age.”3
THE BRAIN IN THE CIDER BOX
Despite Harvey’s meticulous and systematic preservation of Einstein’s brain, a long period of scientiﬁc silence ensued. In a 1978 interview published in Science, 23 years after Einstein’s death, Harvey conceded that “nothing has yet been published” about the sections of brain distributed to various specialists. Emblematic of these scientiﬁc doldrums was storage of the brain fragments “in a jar of formaldehyde that [is]...kept in a cider box, under a beer cooler, in Harvey’s ofﬁce.” Although he entrusted brain specimens to a dozen scientiﬁc investigators, not until collaborations with Marian Diamond in 19854 and Sandra Witelson in 19995 did Harvey think science was any closer to understanding whether the physical structure of Einstein’s brain accounted for his genius.
Both Diamond and Witelson concluded that the parietal lobes of Einstein’s brain (parts of the cerebrum primarily concerned with processing sensory information and with spatial orientation) were anatomically unique. They used markedly different methodologies, however: Diamond counted the cells in the cerebral cortex; Witelson studied the brain’s gross anatomy. Diamond compared cell counts of parts of Einstein’s cerebrum with those from former Veterans’ Administration hospital patients. The specimens were stained to distinguish two types of brain cell: neurons and glial cells. In Einstein’s left parietal cortex, Diamond noted a signiﬁcant increase in glial cells but not neurons. She proposed that the “differential cell counts constituted a potentially meaningful measure of the functional status of the brain” in general, and, in particular, “neuronal:glial ratios in selected regions of Einstein’s brain might reﬂect the enhanced use of this tissue in the expression of his unusual conceptual powers.”
On June 18, 1999, in a headline reminiscent of the heroic age of phrenology 200 years earlier, the New York Times proclaimed “Key to intellect may lie in folds of Einstein’s brain.” Relying on visual inspection and meticulous measurement of a fifth of Einstein’s brain, and on the photographs taken in 1955, Witelson found that Einstein’s inferior parietal lobules were larger than those of normal-intellect controls from the brain bank at McMaster University. This suggested, according to Witelson, early extensive development of the posterior parietal lobes. That development, in turn, displaced to the front the posterior end of the Sylvian ﬁssure, pushing it into the postcentral sulcus (a furrow on the cortical surface). As a consequence, the parietal opercula did not develop. Within the inferior parietal lobule, the supramarginal gyrus (a ridge on the cortical surface) was undivided by a major sulcus. Without that division, a more efﬁcient axonal connectivity of this anomalous architecture may have given Einstein—and here is the payoff of the anatomy lesson—“an extraordinarily large expanse of highly integrated cortex within a functional network.”
In 1985, 30 years after Einstein’s death, scientists began publishing theories about the famous brain preserved in a jar. Their speculation centered on the cerebral cortex, where they claimed to discern suggestive abnormalities, especially in parts of the parietal lobes, that could be associated with mental abilities that may have set Einstein apart. Recent studies have emphasized the loss of parietal opercula and a resulting larger expanse of the inferior parietal lobules, with the super-marginal gyri being undivided by major sulci (grooves). Christopher Wikoff
Not surprisingly, the association of the inferior parietal lobule with visuospatial cognition, mathematical thought, and movement imagery readily lent itself to the hypothesis that Einstein’s mastery of these conceptual areas may have related to his unusual parietal lobe structure. The wider implication was that this post-mortem case study suggested “anatomical features of the parietal cortex may be related to visuospatial intelligence.”
Within days of publication of Witelson’s article in The Lancet, Steven Pinker, one of neuroscience’s most articulate spokesmen, hailed the “elegant study, consistent with the themes of modern cognitive neuroscience.” He observed “no one can claim to have explained Einstein’s genius,” but the study conﬁrmed that the brain is a modular system composed of mostly nonverbal multiple capacities that serve diverse functions, such as vision, spatial sense, and movement. At the close of the 20th century, Einstein’s brain was helping “unify the last great dichotomy in the conceptual cosmos, matter and mind.” Or was it?
CONNECTING BRAIN TO MIND
Although it might be wise to heed John Locke’s 1690 admonition in An Essay Concerning Human Understanding not to “meddle with the physical consideration of the mind,” over the ages investigators have thrown caution to the winds in speculating on the relationship of brain to mind. Our expectations of the study of Einstein’s brain must be viewed in this context.
Scholars of the Middle Ages, echoing the writers of Classical Antiquity, discounted the cerebral cortex as the fountainhead of intellect and proposed that the psyche resided in three brain ventricles, or cavities. Although in 1664 Thomas Willis presciently attributed brain function to gray matter— made up primarily of neuron cell bodies— the ventricular theory did not yield easily, and as late as 1798 Samuel Soemmering proposed that ﬂuid circulating in the ventricles was the seat of the soul. Even in 1858 the shape of cerebral ventricles was posited as a deﬁning human characteristic by the Hunterian professor of the Royal College of Surgeons, Richard Owen.
Franz Joseph Gall’s early 19th century theory of phrenology, which held that external skull conformation reﬂected roughly 35 intellectual and emotional faculties, is regarded today as an example par excellence of pseudoscience. Unfortunately, Gall’s popular legacy is conﬁned to phrenology; his perceptive emphasis on the cerebral cortex as a set of organs with different mental functions passed into oblivion with his death in 1828. Today we can scarcely imagine the revolutionary impact, in a world that had assigned brain function to the ventricles and depicted the cortex as a random arrangement of undifferentiated intestine-like convolutions, of the concept that great regions of mind correspond to great regions of the cerebral cortex. For once, the overused term “paradigm shift” applies.
In 1861, Paul Broca’s post-mortem examination of the brain of Monsieur Leborgne arguably did more than anything else to establish the validity of cortical localization. Leborgne had lost the power of speech 20 years earlier and very well-deﬁned parts of his cerebral cortex were destroyed, including the second and third frontal convolutions, inferior Rolandic area, and ﬁrst temporosphenoidal convolution of the left hemisphere. No longer could the cortex be viewed as a homogeneous expanse of tissue dedicated to the vague global proposition of intellect; what is now called Broca’s area for language had been identiﬁed.
THE PROPOSED BASIS OF GENIUS
The task of localizing functions in different parts of the cerebral cortex continues today, and primary motor and sensory areas have been charted. By contrast, parts of the cerebral cortex called the association cortex, where intermingling and higher processing of multiple sensory inputs occur and where the parietal lobes are, could not be so easily analyzed by correlating disordered functions with physical lesions. Sir William Gowers’ A Manual of Diseases of the Nervous System— the Bible of 19th century neurologists— listed “no motor or sensory symptoms” related to disease of the posterior parietal lobe. A half century later, in 1932, Johns Hopkins University neurosurgeon Walter Dandy wrote, “right parietal lobe (excluding sensory function of the paracentral region) has no known functions,” and deemed the left parietal lobe “by far the most important part of the brain.”
The secrets of parietal lobe function eventually began to yield to specialized examination techniques, however, and the pendulum of scientific opinion swung toward assigning inordinate importance to the relationship between the parietal lobe and the mind. British neurologist Macdonald Critchley reminisced that “a visitor to the prewar neurological centres in Europe might be tempted to remember the Psychiatric Clinic of Vienna as a posterior parietal lobe institute.” Undoubtedly the psychiatrists’ intellectual curiosity was piqued by classic presentations of right parietal lobe lesions in which patients paid no attention to the left side of their environment or contended that their own paralyzed left arms belonged to other people.
One of the mainstays of mapping the cortex, electrical stimulation, has evoked no speciﬁc characteristic motor or sensory response from the cortex of the superior and inferior parietal lobes. Instead, knowledge has been culled from meticulous observations of patients performing everyday acts that exploit this brain region’s complex capabilities. Difﬁculties with such mundane tasks as putting on a coat, drawing a clock face, or identifying a dime by touch have deﬁned the distinctive differences between disordered right and left parietal lobe function.
A person with a disease or injury of the inferior parietal lobe in the dominant (usually left) hemisphere may not be able to perform skilled learned movements; name items; read, write, and calculate; identify his ﬁngers; or distinguish between left and right. In the right (usually nondominant) inferior parietal lobe, however, lesions can cause a person to neglect the left side of extrapersonal space, and have faulty visuospatial integration and impaired drawing. These patients, for example, might put an arm in the wrong sleeve or strenuously deny being afﬂicted in any way. Their performance of tasks involving mental rotation, route ﬁnding, and recognition of objects viewed from an unusual perspective is faulty, and they can experience a general state of confusion. The complex multiplicity of these symptoms arises from the parietal lobe’s location at the crossroads of visual, auditory, somatosensory, and vestibular pathways. Cognitive neuroscientist Marsel Mesulam sees the posterior parietal cortex not as a mere spatial map but as a “critical gateway” for accessing and integrating information necessary for motor strategies that exploit extrapersonal space.6
In just over a century, our view of the parietal lobe has evolved from terra incognita to a proposed basis of genius. What underlies this rapid acceptance of a “supranormal” inferior parietal lobe as the foundation of Einstein’s epoch-defining scientific insight? It is no coincidence that the last 10 years of the 20th century were designated the Decade of the Brain; the success of the scientific method partially replaced older notions of the soul or mind-body dualism with the doctrine that mind and, by extension, intellectual creativity, is the brain’s exclusive output. The Zeitgeist of the computer-driven, late 20th century is firmly grounded in a materialistic basis for mind. The frontal and parietal lobes are the parts of the brain that changed most radically during evolutionary development and, not surprisingly, have kindled the greatest interest as possible wellsprings of intellect.
What we call a “paradigmatic neurologic patient” is also very attractive to researchers. Here a single patient with an isolated brain lesion and clear-cut neurobehavioral abnormality can crystallize our understanding of an aspect of functional neuroanatomy. This is how Broca began to understand the neural basis of language when he held Leborgne’s brain in his hands, and John Harlow found that the “equilibrium or balance, so to speak, between…intellectual faculty and animal propensities” was destroyed by the 3.5-foot-long iron tamping rod that passed through the skull of his patient Phineas Gage in a blasting accident. Similarly, we focus great attention on celebrity illness, from Samuel Johnson reciting the Lord’s prayer in Latin to gauge his recovery from aphasia to former President Ronald Reagan’s Alzheimer’s disease. For better or worse, our culture readily accepts the lessons taught by afflictions of important brains. It is hardly surprising that critical scrutiny may be suspended when secular priests in the white raiment of science reveal that Einstein’s brain is indeed different.
WAS EINSTEIN A “PARIETAL GENIUS”?
Is our ﬁn-de-siecle neuroscience sufﬁciently mature to use Einstein’s brain as a Rosetta Stone for translating neural architecture into the most sublime conceptual achievements? The Nobel Prize for discovering the basic building block of nervous systems, the neuron, was awarded to Ramon y Cajal and Camillo Golgi in 1906, within the memory of living people. If nearly a century later we still cannot precisely explain how patterns of action potentials of 1012 (trillion) neurons lead to a thought, can we presume to relate Einstein’s life and thought to the purported unique structure of his brain? Witelson afﬁrms that we can, citing Einstein’s introspective description of his own scientiﬁc thinking, which relied on images of “visual and muscular type” rather than words. This way of thinking would be congruent with characterizing the parietal lobes as centers of visuospatial cognition. But before we unreservedly accept Einstein as a “parietal genius,” a few specimens of his intellectual legacy warrant examination.
The daunting task of parsing Einstein’s mind becomes inﬁnitely more difﬁcult, given the limited accuracy of internal dialogue in reﬂecting actual cognition.
At the outset, it is treacherous to assume the absolute validity of Einstein’s (or anyone’s) description of his own thought processes. Speaking of his scientiﬁc work, he observed, “There is no logical way to the discovery of these elemental laws. There is only the way of intuition, which is helped by a feeling for the order lying behind appearance.” Einstein clearly believed there was an impenetrable veil preventing an unambiguous view of the mechanics of mind. Terms such as “intuition,” “ﬂash of insight,” and “Eureka” portray immediately recognizable aspects of human thought, demarcating the boundary beyond which cognitive processes are inaccessible to the searchlight of consciousness. Einstein’s rebuttal to quantum theory, “God does not play dice,” was a declaration of faith consistent with the supposition that the moment of scientiﬁc discovery may not be purely logical, nor a proposition with rigorous proof. The daunting task of parsing Einstein’s mind becomes inﬁnitely more difﬁcult, given the limited accuracy of internal dialogue in reﬂecting actual cognition.
Where Einstein’s inner voice is unrevealing, perhaps external events of his life may provide understanding. Einstein did not speak until he was three years old. It has been proposed that the expansion of his parietal lobes, especially in his speech-dominant left hemisphere, in effect intruded on his language areas; early language function was usurped by precocious mathematical and visuospatial capacities. Leaving behind the folklore ﬁgure of a genius who was slow to speak, Einstein’s early academic path showed great promise; he received the highest or next-highest marks in mathematics and Latin. Following a short-lived and intensely religious phase in his eleventh year, he came to regard Euclid as his “holy geometry book,” and between 12 and 16 he taught himself integral and differential calculus. In 1896, as a prerequisite to enrollment at Eidgenossische Technische Hochschule in Zurich, he obtained the Matura (a high school diploma) with superior grades in mathematics and the sciences but less than excellent results in technical and artistic drawing and geography. These grades are difﬁcult to reconcile with an idealized “parietal-lobe prodigy” armed with formidable visuospatial skills.
If we agree with Mesulam’s analysis of the posterior parietal cortex as pivotal in integrating spatial information received via all our senses, it becomes difﬁcult to envision Einstein’s parietal lobe as the crucial element in his key theoretical constructs. Our senses cannot detect the curvature of space (as in the theory of general relativity) or the inﬁnitesimal changes in time and dimension that occur with the velocities encountered in daily existence (as in the theory of special relativity). Einstein’s discoveries were not based on direct sensory experience but were pure thought experiments performed in his imagination. Such experiments are not easily reconciled with the current view of the parietal lobe as a provider of strategies to interact with and integrate direct sensory input from outside oneself.
Einstein was undeniably a genius, but to qualify him as a parietal genius is premature, based on our current and relatively primitive understanding of cortical function. The hypothesis of genius driven by a supranormal parietal lobe does not satisfactorily explain how Einstein’s intellectual productivity changed over time. Like most physicists and mathematicians, his greatest work was accomplished as a young man. In a magniﬁcent creative outburst in 1905, 26-year-old Einstein completed six signiﬁcant papers, including those on special relativity, the e = mc2 equation, and a quantum explanation of the photoelectric effect that led to his Nobel Prize in physics. Ten years later, in his ﬁnal revision of the theory of general relativity, he proclaimed that space is curved and cannot be described by Euclidean geometry.
An inclination to venerate his middle and later years must be tempered by C.P. Snow’s observation that “he wasted the second half of his life” in his quest for a uniﬁed ﬁeld theory that would show the forces of electromagnetism and gravity stemming from one grand overarching principle. This holy grail eluded the incessant mental effort of the man “universally recognized at 37 as the greatest theoretical physicist of his age, the equal of Newton.” As scientiﬁc incandescence dimmed in his later years, Einstein transformed into a complete internationalist and the voice of liberal science—the prophet of negotiation and peace for a generation.
Fitting Einstein’s multifaceted complexity and creativity into a Procrustean bed of cortical localization faces another challenge, the actual anatomy of the parietal lobes. In 1951, Critchley, who wrote the classic monograph, The Parietal Lobes, said, “Strictly speaking there is no such structure as a parietal lobe; for it is only an anatomical convention; an empirical demarcation which has been pegged out on the surface of the brain. No natural boundary can be said to exist either behind or below. The traditional gyri and sulci are unhelpful landmarks and are often a matter of guesswork.” Subtle distinctions and the variability of cortical topography led to a highly technical argument between neuroscientist Albert Galaburda and Witelson in The Lancet about just what could seen in Einstein’s brain.7 To give readers the ﬂavor of this dispute: Galaburda contended that a parietal operculum is present and consequently the inferior parietal lobule is not enlarged as Witelson claimed. Witelson countered that Galaburda mistook the sulcus retrocentralis transversus for the post-central sulcus, and Einstein’s brain must therefore lack a parietal operculum, allowing for an augmented inferior parietal lobule. Even when we make a leap of faith that the form of the cerebral cortex can tell us something about a person’s higher faculties, we must temper the neuroanatomist’s interpretation with the knowledge that, as described in The Isocortex of Man, there is a “bewildering variety of sulcal patterns in the parietal lobe reﬂecting that the brain has a particularly high degree of ‘developmental freedom.’… The brain is the most individualistic of all organs.”
Leaving aside the anatomical difﬁculties in deciding whether a particular individual has enlarged parietal lobes, do others with bigger-than-normal parietal lobes also have extraordinary Einstein-like potential? One group with functionally enlarged parietal lobes are those who have been blind from an early age and who read Braille— a formidable tactile sensory task in which a person extracts the meaning of 60 to 120 words from 2500 dots each minute. In normal individuals, tactile discrimination is performed by the parietal lobes, but visual processing occurs in the occipital lobes. Researchers have discovered, however, that people with early-onset blindness who receive pulses of magnetic stimulation to their occipital cortex show a signiﬁcant increase in Braille reading errors. The occipital lobes, rather than responding to visual stimuli, become extensions of the parietal lobes in processing sensory information; we might say that the functional boundaries of the parietal lobes have expanded. Despite the expansion, there is no widespread evidence of an association between early blindness and prowess in, for example, theoretical physics.
Other difﬁculties present themselves. As related by Harvey, “Unfortunately we have [only] one brain” of an Einstein. Scientiﬁc certainty tends to be conﬁrmed by multiple subjects or experiments, so it is hard to draw deﬁnite conclusions from a single specimen, no matter how exceptional. Furthermore, in assuming that close observation of dead neural tissue can tell us about living thought, we may face the plight of Samuel Coleridge’s guide, who “points with his ﬁnger to a heap of stones and tells the Traveler, ‘That is Babylon, or Persepolis.’ ” There may be ﬁnite limits to what can be learned from static neuroanatomy divorced from neurophysiology. Before functional neuroimaging, most knowledge of the localization of brain functions came from meticulous clinical observations of patients with cerebral lesions. Although this approach may shed light on deﬁciencies, it will not necessarily yield useful information about people with overabundant intellectual attributes.
THE CULT OF GENIUS
Given our inadequate knowledge of the relation between brain function and anatomy, and our inability to physically pinpoint the origins of ideas and opinions, why does Einstein’s brain exert such irresistible attraction for neuroscientists and people from all walks of life?
We seem to live in an age of the gifted, where the highest aspirations for our children include enrollment in school programs for the gifted to bring out the untapped genius of little Einsteins. The burgeoning cult of genius is reﬂected in our evolving language. According to The Oxford English Dictionary, before the 18th century, genius referred to the pagan belief in a God or spirit allotted to every person at birth to determine the person’s character and fortunes. By the 18th century, genius was no longer an external agent, but “native intellectual power of an exalted type, such as is attributed to those who are esteemed greatest in any department of art, speculation, or practice.” The transition of genius from an externally God-given quality to an innate endowment ﬁts well in our era of the self-realizing individual. As we seek to understand what makes a genius tick, the better to emulate him, what most promising place to begin than with the 20th century icon of genius, Albert Einstein?
Even the relationship between neurologic lesions and intellectual capacities is not straightforward. For example, in 1980 British neurologist John Lorber reported in Science that a patient with severe hydrocephalus had, “instead of the normal 4.5 centimeter thickness of brain tissue between the ventricles and the cortical surface...just a thin layer of mantle measuring a millimeter or so. His cranium is ﬁlled mainly with cerebrospinal ﬂuid.” Rather than showing devastating intellectual impairment, however, the patient was socially normal, had an IQ of 126, and gained a ﬁrst-class honors degree in mathematics. Similarly, according to V. S. Ramachandran, anthropologists assert that the great leap in technological sophistication, widespread cave art, clothes, and stereotyped dwellings occurred around 40 thousand years ago, even though the brain achieved its present size almost a million years earlier. We may follow a cultural mandate in studying the brain of a genius, but gaps in our knowledge of the physical and structural basis of cognition are humbling.
Would it have been better if Harvey had placed Einstein’s brain back in the cranial cavity and let it blaze into ashes at the Ewing Crematorium on April 18, 1955? Most neuroscientists, ﬁrmly rooted in the prevalent philosophy that mind is deﬁned by brain structure, would deeply regret the loss of a unique opportunity to investigate the neuroanatomy of arguably the 20th century’s most original thinker. In contrast, Wilder Penﬁeld, whose neurosurgical explorations established the hallmark of localization, the cortical homunculus (the “little man” mapping body parts onto the cerebral hemispheres), was not sanguine about ﬁnding a solution to the mystery of the mind:
Because it seems to me certain that it will always be quite impossible to explain the mind on the basis of neuronal action within the brain, and because it seems to me that the mind develops and matures independently throughout the individual’s life as though it were a continuing element, and because a computer (which the brain is) must be programmed and operated by an agency capable of independent understanding, I am forced to choose the proposition that our being is to be explained on the basis of two fundamental elements.8
Penﬁeld’s high standing in the pantheon of neuroscience makes it difﬁcult to ignore his endorsement of mind-brain dualism. But before we consign Einstein’s intellect to the realm of the unknowable or blindly revere his brain as a sacred talisman, we must recall that neuroscience is still a young discipline. Scientists may not have focused yet on the critical features that determine intellectual function. In the words of Ramon y Cajal, “intellectual power and its most noble expressions, talent and genius, do not depend on the size or number of cerebral neurons, but on the richness of their connective processes, or in other words on the complexity of the association pathways to short and long distances.” Deeper understanding of the staggering intricacy of the estimated 1015 (one thousand trillion) cerebral synapses may tell us a great deal more than would counting neurons or looking at the conﬁguration of the brain.
Roger Penrose, Oxford mathematician and author of The Emperor’s New Mind, and Stuart Hameroff, an anesthesiologist at the University of Arizona, have even questioned the assumption that the neuron is the building block of cognition. They say consciousness may not emerge from a critical mass and arrangement of neurons, but from quantum computations based on the changing shapes of tubulin proteins that are part of the neuron’s structural frame. Although recent work suggests the brain is a terrible environment for quantum computations, this innovative questioning of previous scientiﬁc assumptions may offer an escape from Penﬁeld’s dilemma.
Even if we ask the right questions, we must have adequate technology to provide the right answers. Examining the anatomy of Einstein’s brain provides only indirect evidence of his physiology of thinking. Before the end of the 20th century, we had a few limited techniques, such as electroencephalography or evoked potentials, to study the physiology of the living brain. With positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), we are now able to obtain snapshots of activity that occurs in the brain while a person is engaged in cognitive tasks. For example, a PET scan shows increased cerebral blood ﬂow to the primary visual cortex when the subject views a checkerboard target. It is now being used to link brain regions with more complex cognitive tasks.
Recently, John Duncan at Cambridge used PET to delineate what he believes is a neural basis for general intelligence.9 Volunteers performing spatial, verbal, and perceptuomotor tasks had increased cerebral metabolism in the lateral frontal cortex in one or both hemispheres. PET scanning suggests that general intelligence (sometimes called “g”) needed to perform these diverse tasks arises from a speciﬁc frontal lobe system rather than from multiple brain areas. Further reﬁnements in neuroimaging of the functioning brain will help investigators tease out other neuronal circuits and patterns that underlie the human endowments of cognition, creativity, and emotion—even endowments as extraordinary as those of an Einstein.
The intense interest in Einstein’s brain is emblematic of our abiding curiosity about intellect in general and genius in particular. We may ask too much of this remarkable specimen when we expect 240 blocks of defunct neurons to blaze a pathway to genius, but neuroscientists will persevere in the study of Einstein’s brain as a potential key to understanding the brain for cultural and scientiﬁc reasons.
Einstein’s brain is now at the Department of Pathology at the Medical Center at Princeton. Elliot Krauss was entrusted with the brain because “Thomas Harvey wanted to make sure that the brain was put in the right hands to keep the study alive.”10 As Krauss deliberates over the best scientiﬁc use of this celebrated specimen, Einstein’s brain ﬂoats in two glass jars, quietly waiting to assume its place in history as an avatar of genius or an anatomical curio.