Probing the Mysteries of the Human Mind
V.S. Ramachandran, M.D., Ph.D.,
and Sandra Blakeslee
l. Neurology-Popular works. 2. Brain-Popular works. 3. Neurosciences-Popular works.
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Book Details
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Pages
| 360 p |
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ISBN
| 0-688-15247-3 |
Copyright©
| 1998 by V.S. Ramachandran and Sandra Blakeslee |
By the deficits, we may know the talents, by the exceptions, we may
discern the rules, by studying pathology we may construct a model
of health. And-most important-from this model may evolve the
insights and tools we need to affect our own lives, mold our own
destinies, change ourselves and our society in ways that, as yet, we
can only imagine.
-LAURENCE MILLER
The world shall perish not for lack of wonders, but for lack of wonder.
-J.B.S. HALDANE
Preface
In any field, find the strangest thing and then explore it.
-JOHN ARCHIBALD WHEELER
This book has been incubating in my head for many years, but I never
quite got around to writing it. Then, about three years ago, I gave the
Decade of the Brain lecture at the annual meeting of the Society for
Neuroscience to an audience of over four thousand scientists, discussing
many of my findings, including my studies on phantom limbs, body image
and the illusory nature of the self. Soon after the lecture, I was
barraged with questions from the audience: How does the mind influence
the body in health and sickness? How can I stimulate my right brain
to be more creative? Can your mental attitude really help cure asthma
and cancer? Is hypnosis a real phenomenon? Does your work suggest
new ways to treat paralysis after strokes? I also got a number of requests
from students, colleagues and even a few publishers to undertake writing
a textbook.
Textbook writing is not my cup of tea, but I thought a
popular book on the brain dealing mainly with my own experiences
working with neurological patients might be fun to write. During the
last decade or so, I have gleaned many new insights into the workings
of the human brain by studying such cases, and the urge to communicate
these ideas is strong. When you are involved in an enterprise as exciting
as this, it's a natural human tendency to want to share your ideas with
others. Moreover, I feel that I owe it to taxpayers, who ultimately support
my work through grants from the National Institutes of Health.
Popular science books have a rich, venerable tradition going as far
back as Galileo in the seventeenth century. Indeed, this was Galileo's
main method of disseminating his ideas, and in his books he often aimed
barbs at an imaginary protagonist, Simplicia-an amalgam of his professors.
Almost all of Charles Darwin's famous books, including The Origin
of Species, The Descent of Man, The Expression of Emotions in Animals
and Men, The Habits of Insectivorous Plants-but not his two-volume
monograph on barnacles!-were written for the lay reader at the request
of his publisher, John Murray. The same can be said of the many works
of Thomas Huxley, Michael Faraday, Humphry Davy and many other
Victorian scientists. Faraday's Chemical History of a Candle, based on
Christmas lectures that he gave to children, remains a classic to this day.
I must confess that I haven't read all these books, but I do owe a
heavy intellectual debt to popular science books, a sentiment that is echoed
by many of my colleagues. Dr. Francis Crick of the Salk Institute
tells me that Erwin Schrodinger's popular book What Is Life? contained
a few speculative remarks on how heredity might be based on a chemical
and that this had a profound impact on his intellectual development,
culminating in his unraveling the genetic code together with James Watson
. Many a Nobel Prize-winning physician embarked on a research career
after reading Paul de Kruif 's The Microbe Hunters, which was
published in 1926 . My own interest in scientific research dates back to
my early teens, when I read books by George Gamow, Lewis Thomas,
and Peter Medawar, and the flame is being kept alive by a new generation
of writers-Oliver Sacks, Stephen Jay Gould, Carl Sagan, Dan Dennett,
Richard Gregory, Richard Dawkins, Paul Davies, Colin Blakemore and
Steven Pinker.
About six years ago I received a phone call from Francis Crick, the
codiscoverer of the structure of deoxyribonucleic acid ( DNA) , in which
he said that he was writing a popular book on the brain called The Aston ishing
Hypothesis. In his crisp British accent, Crick said that he had completed
a first draft and had sent it to his editor, who felt that it was
extremely well written but that the manuscript still contained jargon that
would be intelligible only to a specialist. She suggested that he pass it
around to some lay people . "I say, Rama," Crick said with exasperation,
"the trouble is, I don 't know any lay people . Do you know any lay people
I could show the book to? " At first I thought he was joking, but then
realized he was perfectly serious . I can't personally claim not to know
any lay people, but I could nevertheless sympathize with Crick's plight.
When writing a popular book, professional scientists always have to walk
a tightrope between making the book intelligible to the general reader,
on the one hand, and avoiding oversimplification, on the other, so that
experts are not annoyed. My solution has been to make elaborate use of
end notes, which serve three distinct functions : First, whenever it was
necessary to simplifY an idea, my cowriter, Sandra Blakeslee , and I resorted
to notes to qualifY these remarks, to point out exceptions and to
make it clear that in some cases the results are preliminary or controversial
. Second, we have used notes to amplifY a point that is made only
briefly in the main text-so that the reader can explore a topic in greater
depth . The notes also point the reader to original references and credit
those who have worked on similar topics . I apologize to those whose
works are not cited; my only excuse is that such omission is inevitable in
a book such as this ( for a while the notes threatened to exceed the main
text in length ) . But I 've tried to include as many pertinent references as
possible in the bibliography at the end, even though not all of them are
specifically mentioned in the text.
This book is based on the true-life stories of many neurological patients.
To protect their identity, I have followed the usual tradition of
changing names, circumstances and defining characteristics throughout
each chapter. Some of the "cases" I describe are really composites of
several patients, including classics in the medical literature, as my purpose
has been to illustrate salient aspects of the disorder, such as the neglect
syndrome or temporal lobe epilepsy. When I describe classic cases (like
the man with amnesia known as H . M . ), I refer the reader to original
sources for details . Other stories are based on what are called single-case
studies, which involve individuals who manifest a rare or unusual syndrome.
A tension exists in neurology between those who believe that the most
valuable lessons about the brain can be learned from statistical analyses
involving large numbers of patients and those who believe that doing
the right kind of experiments on the right patients-even a single patient-
can yield much more useful information. This is really a silly debate
since its resolution is obvious: It's a good idea to begin with
experiments on single cases and then to confirm the findings through
studies of additional patients . By way of analogy, imagine that I cart a
pig into your living room and tell you that it can talk. You might say,
"Oh, really? Show me . " I then wave my wand and the pig starts talking.
You might respond, "My God! That's amazing ! " You are not likely to
say, "Ah, but that's just one pig. Show me a few more and then I might
believe you . " Yet this is precisely the attitude of many people in my field .
I think it's fair to say that, in neurology, most of the major discoveries
that have withstood the test of time were, in fact, based initially on singlecase
studies and demonstrations . More was learned about memory from
a few days of studying a patient called H . M . than was gleaned from
previous decades of research averaging data on many subjects . The same
can be said about hemispheric specialization ( the organization of the
brain into a left brain and a right brain, which are specialized for different
functions ) and the experiments carried out on two patients with so-called
split brains (in whom the left and right hemispheres were disconnected
by cutting the fibers between them ) . More was learned from these two
individuals than from the previous fifty years of studies on normal people .
In a science still in its infancy ( like neuroscience and psychology)
demonstration-style experiments play an especially important role . A classic
example is Galileo's use of early telescopes . People often assume that
Galileo invented the telescope, but he did not. Around 1607, a Dutch
spectacle maker, Hans Lipperhey, placed two lenses in a cardboard tube
and found that this arrangement made distant objects appear closer. The
device was widely used as a child's toy and soon found its way into
country fairs throughout Europe , including France . In 1609 , when Galileo
heard about this gadget, he immediately recognized its potential .
Instead o f spying o n people and other terrestrial objects, h e simply raised
the tube to the sky-something that nobody else had done . First he
aimed it at the moon and found that it was covered with craters, gullies
and mountains-which told him that the so-called heavenly bodies are,
contrary to conventional wisdom, not so perfect after all: They are full
of flaws and imperfections, open to scrutiny by mortal eyes just like objects
on earth . Next he directed the telescope at the Milky Way and
noticed instantly that far from being a homogeneous cloud ( as people
believed), it was composed of millions of stars. But his most startling
discovery occurred when he peered at Jupiter, which was known to be a
planet or wandering star. Imagine his astonishment when he saw three
tiny dots near Jupiter (which he initially assumed were new stars ) and
witnessed that after a few days one disappeared. He then waited for a
few more days and gazed once again at Jupiter, only to find that not
only had the missing dot reappeared, but there was now an extra dot-a
total of four dots instead of three. He understood in a flash that the four
dots were Jovian satellites-moons just like ours-that orbited the
planet. The implications were immense . In one stroke, Galileo had
proved that not all celestial bodies orbit the earth, for here were four
that orbited another planet, Jupiter. He thereby dethroned the geocentric
theory of the universe, replacing it with the Copernican view that
the sun, not the earth, was at the center of the known universe . The
clinching evidence came when he directed his telescope at Venus and
found that it looked like a crescent moon going though all the phases,
just like our moon, except that it took a year rather than a month to do
so . Again, Galileo deduced from this that all the planets were orbiting
the sun and that Venus was interposed between the earth and the sun .
All this from a simple cardboard tube with two lenses . No equations, no
graphs, no quantitative measurements: "just" a demonstration.
When I relate this example to medical students, the usual reaction is,
Well, that was easy during Galileo's time, but surely now in the twentieth
century all the major discoveries have already been made and we can't
do any new research without expensive equipment and detailed quantitative
methods. Rubbish ! Even now amazing discoveries are staring at
you all the time, right under your nose . The difficulty lies in realizing
this. For example , in recent decades all medical students were taught that
ulcers are caused by stress, which leads to excessive acid production that
erodes the mucosal lining of the stomach and duodenum, producing the
characteristic craters or wounds that we call ulcers . And for decades the
treatment was either antacids, histamine receptor blockers, vagotomy
( cutting the acid-secreting nerve that innervates the stomach ) or even
gastrectomy ( removal of part of the stomach. ) But then a young resident
physician in Australia, Dr. Bill Marshall, looked at a stained section of a
human ulcer under a microscope and noticed that it was teeming with
Helicobacter pylori-a common bacterium that is found in a certain proportion
of healthy individuals . Since he regularly saw these bacteria in
ulcers, he started wondering whether perhaps they actually caused ulcers .
When he mentioned this idea to his professors, he was told, "No way.
That can't be true . We all know ulcers are caused by stress. What you
are seeing is just a secondary infection of an ulcer that was already in place . "
But Dr. Marshall was not dissuaded and proceeded to challenge the
conventional wisdom . First he carried out an epidemiological study,
which showed a strong correlation between the distribution of Helicobacter
species in patients and the incidence of duodenal ulcers . But this
finding did not convince his colleagues, so out of sheer desperation,
Marshall swallowed a culture of the bacteria, did an endoscopy on himself
a few weeks later and demonstrated that his gastrointestinal tract was
studded with ulcers ! He then conducted a formal clinical trial and
showed that ulcer patients who were treated with a combination of antibiotics,
bismuth and metronidazole ( Flagyl, a bactericide ) recovered at
a much higher rate-and had fewer relapses-than did a control group
given acid-blocking agents alone .
I mention this episode to emphasize that a single medical student or
resident whose mind is open to new ideas and who works without sophisticated
equipment can revolutionize the practice of medicine . It is in
this spirit that we should all undertake our work, because one never
knows what nature is hiding.
I'd also like to say a word about speculation, a term that has acquired
a pejorative connotation among some scientists . Describing someone's
idea as "mere speculation" is often considered insulting. This is unfortunate
. As the English biologist Peter Medawar has noted, "An imagi
native conception of what might be true is the starting point of all great
discoveries in science . " Ironically, this is sometimes true even when the
speculation turns out to be wrong. Listen to Charles Darwin: "False facts
are highly injurious to the progress of science for they often endure long;
but false hypotheses do little harm, as everyone takes a salutary pleasure
in proving their falseness; and when this is done, one path toward error
is closed and the road to truth is often at the same time opened. "
Every scientist knows that the best research emerges from a dialectic
between speculation and healthy skepticism . Ideally the two should coexist
in the same brain, but they don't have to . Since there are people
who represent both extremes, all ideas eventually get tested ruthlessly.
Many are rejected (like cold fusion ) and others promise to turn our views
topsy turvy (like the view that ulcers are caused by bacteria) .
Several of the findings you are going to read about began as hunches
and were later confirmed by other groups (the chapters on phantom
limbs, neglect syndrome, blindsight and Capgras' syndrome ) . Other
chapters describe work at an earlier stage, much of which is frankly speculative
(the chapter on denial and temporal lobe epilepsy ) . Indeed, I will
take you at times to the very limits of scientific inquiry.
I strongly believe , however, that it is always the writer's responsibility
to spell out clearly when he is speculating and when his conclusions are
clearly warranted by his observations . I 've made every effort to preserve
this distinction throughout the book, often adding qualifications, disclaimers
and caveats in the text and especially in the notes. In striking
this balance between fact and fancy, I hope to stimulate your intellectual
curiosity and to widen your horizons, rather than to provide you with
hard and fast answers to the questions raised.
The famous saying "May you live in interesting times" has a special
meaning now for those of us who study the brain and human behavior.
On the one hand, despite two hundred years of research, the most basic
questions about the human mind-How do we recognize faces? Why do
we cry? Why do we laugh? Why do we dream? and Why do we enjoy
music and art?-remain unanswered, as does the really big question:
What is consciousness? On the other hand, the advent of novel experimental
approaches and imaging techniques is sure to transform our understanding
of the human brain. What a unique privilege it will be for
our generation-and our children's-to witness what I believe will be
the greatest revolution in the history of the human race: understanding
ourselves . The prospect of doing so is at once both exhilarating and disquieting.
There is something distinctly odd about a hairless neotenous primate
that has evolved into a species that can look back over its own shoulder
and ask questions about its origins . And odder still, the brain can not
only discover how other brains work but also ask questions about its own
existence : Who am I ? What happens after death ? Does my mind arise
exclusively from neurons in my brain? And if so, what scope is there for
free will? It is the peculiar recursive quality of these questions-as the
brain struggles to understand itself-that makes neurology fascinating.
Table of Contents
Foreword by Oliver Sacks, M . D . vii
Preface XI
Chapter l: The Phantom Within 1
Chapter 2 : "Knowing Where to Scratch" 2 1
Chapter 3: Chasing the Phantom 39
Chapter 4: The Zombie i n the Brain 63
Chapter 5: The Secret Life of James Thurber 8 5
Chapter 6 : Through the Looking Glass 113
Chapter 7: The Sound of One Hand Clapping 127
Chapter 8 : "The Unbearable Likeness o f Being" 1 5 8
Chapter 9: God and the Limbic System 174
Chapter 10 : The Woman Who Died Laughing 199
Chapter 1 1 : "You Forgot t o Deliver the Twin" 2 12
Chapter 12 : Do Martians See Red? 227
Acknowledgments 2 5 9
Notes 263
Bibliography and Suggested Reading 299
Index 3 14
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