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Transcript
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
Forty-five years after Albert Einstein’s death we still seek an explanation of his extraordinary gifts. Headlines have
trumpeted that he was a “parietal genius,” or that his brain had more of a particular kind of cell, or that the key to
his intellect lay in the unusual folds of his brain.
But wait, says clinical neurologist Frederick E. Lepore (who lives three blocks from Einstein’s house in Princeton),
we may be indulging in a modern version of phrenology. He examines how far brain science has come in linking
mental capabilities to specific brain areas, and how far it has to go. Our fascination with Einstein’s brain, says
Lepore, reveals more about us—our assumptions about the brain and our reverence for genius—than about
Einstein.
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 his former mentor, Fritz Lewy, to dissect it.
Lewy, who was first to describe the specific neurological changes that demarcate Parkinson’s disease, and his
Berlin-trained technician 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.
© The DANA Foundation. All rights reserved.
1
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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.”
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?
© The DANA Foundation. All rights reserved.
2
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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.
© The DANA Foundation. All rights reserved.
3
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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 mindbody 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.
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
© The DANA Foundation. All rights reserved.
4
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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
© The DANA Foundation. All rights reserved.
5
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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.
© The DANA Foundation. All rights reserved.
6
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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 mindbrain 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
© The DANA Foundation. All rights reserved.
7
THE DANA REVIEW
http://www.g2conline.info/854
Title: Dissecting Genius: Einstein’s Brain and the Search
for the Neural Basis of Intellect
Author: Frederick E. Lepore
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.
References
1. Author’s interview with Thomas Harvey, M.D., June 4, 2000.
2. Bailey, P, Von Bonin, G. The Isocortex of Man. Urbana: University of Illinois Press, 1951.
3. Editorial. Brain that rocked physics rests in cider box. Science 1978;201:696
4. Diamond MC, Scheibel AB, Murphy GM Jr, Harvey T. On the brain of a scientist: Albert Einstein.
Experimental Neurology 1985;88(1):198-204
5. Witelson SF, Kigar DL, Harvey T. The exceptional brain of Albert Einstein. Lancet 1999;353:2149-53.
6. Mesulam M-M. Principles of Behavioral and Cognitive Neurology, 2nd ed. New York: Oxford
University Press, 2000.
7. Galaburda AM. Albert Einstein’s brain. Lancet 1999; 354: 1821.
8. Penfield W. The Mystery of the Mind. Princeton: Princeton University Press, 1975:80
9. Duncan J, Seitz RJ, Kolodny J, et al. A neural basis for general intelligence. Science 2000; 289:457460.
10. Paterniti M. Driving Mr. Albert: A Trip Across America with Einstein’s Brain. New York: The Dial
Press, 2000.
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