The Human Brain Book: An Illustrated Guide to Its Structure, Function, and Disorders

266 Pages·2019·65.54 MB·English

by  Rita Carter

T H E
HUMAN
BRAIN
BOO K
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T H E
HUMAN
BRAIN
BOO K
R I TA C A RT E R
SU S A N A L D R I D G E
M A R T Y N PA G E
S T E V E PA R K E R
CONSULTANTS Professor Chris Fr ith,
Professor Uta Fr ith, and Dr. Melanie Shulman
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CONTENTS
NO ORDINARY ORGAN 6 THE CEREBRAL CORTEX 66
BRAIN CELLS 70
INVESTIGATING THE BRAIN 8 NERVE IMPULSES 72
LANDMARKS IN NEUROSCIENCE 10 BRAIN MAPPING
AND SIMULATION 74
SCANNING THE BRAIN 12
A JOURNEY THROUGH THE BRAIN 14
THE SENSES 76
THE BRAIN AND THE BODY 36 HOW WE SENSE THE WORLD 78
BRAIN FUNCTIONS 38 THE EYE 80
THE NERVOUS SYSTEM 40 THE VISUAL CORTEX 82
THE BRAIN AND THE VISUAL PATHWAYS 84
NERVOUS SYSTEM 42
VISUAL PERCEPTION 86
BRAIN SIZE, ENERGY USE,
AND PROTECTION 44 SEEING 88
EVOLUTION 48 THE EAR 90
MAKING SENSE OF SOUND 92
HEARING 94
BRAIN ANATOMY 50
SMELL 96
BRAIN STRUCTURES 52
PERCEIVING SMELL 98
BRAIN ZONES AND PARTITIONS 56
TASTE 100
THE NUCLEI OF THE BRAIN 58
TOUCH 102
THE THALAMUS, HYPOTHALAMUS,
AND PITUITARY GLAND 60 THE SIXTH SENSE 104
THE BRAIN STEM AND CEREBELLUM 62 PAIN SIGNALS 106
THE LIMBIC SYSTEM 64 EXPERIENCING PAIN 108
DK LONDON
SENIOR EDITOR Peter Frances
PROJECT EDITOR Ruth O’Rourke-Jones
PROJECT ART EDITOR Francis Wong
US EDITOR Jennette ElNaggar
THIRD EDITION US EXECUTIVE EDITOR Lori Cates Hand
DK DELHI MANAGING EDITOR Angeles Gavira Guerrero
SENIOR EDITOR Rupa Rao MANAGING ART EDITOR Michael Duffy
JACKET DESIGN DEVELOPMENT
ART EDITOR Sonakshi Singh
MANAGING EDITOR Rohan Sinha MANAGER Sophia MTT
MANAGING ART EDITOR Sudakshina Basu PRODUCER, PREPRODUCTION Gillian Reid
DTP DESIGNER Bimlesh Tiwary SENIOR PRODUCER Meskerem Berhane
PICTURE RESEARCHER Sumedha Chopra ASSOCIATE PUBLISHER Liz Wheeler
PICTURE RESEARCH MANAGER Taiyaba Khatoon ART DIRECTOR Karen Self
PREPRODUCTION MANAGER Balwant Singh DESIGN DIRECTOR Phil Ormerod
PRODUCTION MANAGER Pankaj Sharma PUBLISHING DIRECTOR Jonathan Metcalf
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MOVEMENT AND CONTROL 110 MEMORY 154 BRAIN MONITORING
AND STIMULATION 202
REGULATION 112 THE PRINCIPLES OF MEMORY 156
STRANGE BRAINS 204
THE NEUROENDOCRINE THE MEMORY WEB 158
SYSTEM 114
LAYING DOWN A MEMORY 160
PLANNING A MOVEMENT 116 DEVELOPMENT AND AGING 206
RECALL AND RECOGNITION 162
EXECUTING A MOVEMENT 118 THE INFANT BRAIN 208
UNUSUAL MEMORY 164
UNCONSCIOUS ACTION 120 CHILDHOOD AND ADOLESCENCE 210
MIRROR NEURONS 122 THE ADULT BRAIN 212
THINKING 166
THE AGING BRAIN 214
INTELLIGENCE 168
EMOTIONS AND FEELINGS 124 THE BRAIN OF THE FUTURE 216
CREATIVITY AND HUMOR 170
THE EMOTIONAL BRAIN 126
BELIEF AND SUPERSTITION 172
CONSCIOUS EMOTION 128 DISEASES AND DISORDERS 220
ILLUSIONS 174
DESIRE AND REWARD 130 THE DISORDERED BRAIN 222
DIRECTORY OF DISORDERS 224
CONSCIOUSNESS 176
THE SOCIAL BRAIN 132
WHAT IS CONSCIOUSNESS? 178
GLOSSARY 250
SEX, LOVE, AND
LOCATING CONSCIOUSNESS 180
SURVIVAL 134 INDEX 256
ATTENTION AND
EXPRESSION 136 ACKNOWLEDGMENTS 264
CONSCIOUSNESS 182
THE SELF AND OTHERS 138
THE IDLING BRAIN 184
THE MORAL BRAIN 140
ALTERING CONSCIOUSNESS 186
SLEEP AND DREAMS 188
LANGUAGE AND
TIME 190
COMMUNICATION 142
THE SELF AND
GESTURES AND BODY
CONSCIOUSNESS 192
LANGUAGE 144
THE ORIGINS OF
LANGUAGE 146 THE INDIVIDUAL BRAIN 194
THE LANGUAGE AREAS 148 NATURE AND NURTURE 196
A CONVERSATION 150 INFLUENCING THE BRAIN 198
READING AND WRITING 152 PERSONALITY 200
FIRST EDITION CREATIVE TECHNICAL SUPPORT photocopying, recording, or otherwise), without the
prior written permission of the copyright owner.
Adam Brackenbury, John Goldsmid
Published in Great Britain by Dorling Kindersley Limited.
SENIOR EDITOR Peter Frances
MANAGING EDITOR Sarah Larter
A catalog record for this book is available from the
SENIOR ART EDITOR Maxine Lea
Library of Congress.
SENIOR MANAGING ART EDITOR Phil Ormerod
PROJECT EDITORS Nathan Joyce,
PUBLISHING MANAGER Liz Wheeler ISBN 978-1-4654-7954-9
Ruth O’Rourke, Miezan van Zyl
REFERENCE PUBLISHER Jonathan Metcalf DK books are available at special discounts when
EDITORS Salima Hirani, Katie John, purchased in bulk for sales promotions, premiums,
ART DIRECTOR Bryn Walls
fund-raising, or educational use. For details, contact:
Rebecca Warren
DK Publishing Special Markets, 345 Hudson Street,
ILLUSTRATORS Medi-Mation, Peter Bull Art Studio
PROJECT ART EDITORS Alison Gardner, New York, New York 10014
This American Edition, 2019
NO ORDINARY ORGAN
The human brain is like nothing else. As organs go, it is not especially generates the emotions, perceptions, and thoughts that guide your
prepossessing—3lb (1.4kg) or so of rounded, corrugated fesh with behavior. Then it directs and executes your actions. Finally, it is
a consistency somewhere between jelly and cold butter. It doesn’t responsible for the conscious awareness of the mind itself.
expand and shrink like the lungs, pump like the heart, or secrete
visible material like the bladder. If you sliced off the top of someone’s THE DYNAMIC BRAIN
head and peered inside, you wouldn’t see much happening at all. Until about 100 years ago, the only evidence that brain and mind
were connected was obtained from “natural experiments”—accidents
SEAT OF CONSCIOUSNESS in which head injuries created aberrations in their victims’ behavior.
Given this, it is perhaps not surprising that for centuries the contents Dedicated physicians mapped out areas of the cerebral landscape by
of our skulls were regarded as relatively unimportant. When they observing the subjects of such experiments while they were alive—
mummifed their dead, the ancient Egyptians scooped out the brains then matching their defcits to the damaged areas of their brains. It
and threw them away, yet carefully preserved the heart. The Ancient was slow work because the scientists had to wait for their subjects to
Greek philospher, Aristotle, thought the brain was a radiator for die before they could look at the physiological evidence. As a result,
cooling the blood. René Descartes, the French scientist, gave it a until the early 20th century, all that was known about the physical
little more respect, concluding that it was a sort of antenna by which basis of the mind could have been contained in a single volume.
the spirit might commune with the body. It is only now that the full Since then, scientifc and technological advances have fueled a
wonder of the brain is being realized. neuroscientifc revolution. Powerful microscopes made it possible
The most basic function of the brain is to keep the rest of the to look in detail at the brain’s intricate anatomy. A growing
body alive. Among your brain’s 100 billion neurons, some regulate understanding of electricity allowed the dynamics of the brain to
your breathing, heartbeat, and blood pressure and others control be recognized and then, with the advent of electroencephalography
hunger, thirst, sex drive, and sleep cycle. In addition to this, the brain (EEG), to be observed and measured. Finally, the arrival of
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functional brain imaging machines allowed scientists to look inside studies reveals the brain to be an astonishingly complex, sensitive
the living brain and see its mechanisms at work. In the last 20 years, system in which each part affects almost every other. “High level”
positron emission tomography (PET), functional magnetic resonance cognition performed by the frontal lobes, for instance, feeds back to
imaging (fMRI), and, most recently, magnetic encephalography affect sensory experience—so what we see when we look at an object
(MEG) have among them produced an ever more detailed map of is shaped by expectation as well as by the effect of light hitting the
the brain’s functions. retina. Conversely, the brain’s most sophisticated products can
depend on its lowliest mechanisms. Intellectual judgments, for
LIMITLESS LANDSCAPE example, are driven by the body reactions that we feel as emotions,
Today we can point to the circuitry that keeps our vital processes and consciousness can be snuffed out by damage to the humble
going, the cells that produce our neurotransmitters, the synapses brainstem. To confuse things further, the system doesn’t stop at the
where signals leap from cell to cell, and the nerve fbers that convey neck but extends to the tips of your toes. Some would argue it even
pain or move our limbs. We know how our sense organs turn light goes beyond—to encompass other minds with which it interacts.
rays and sounds waves into electrical signals, and we can trace the Neuroscientifc investigation of the brain is very much a work
routes they follow to the specialized areas of cortex that respond to in progress and no one knows what the fnished picture will look
them. We know that such stimuli are weighed, valued, and turned like. It may be that the brain is so complicated that it can never
into emotions by the amygdala—a tiny nugget of tissue that punches understand itself entirely. So this book cannot be taken as a full
well above its weight. We can see the hippocampus retrieve a memory, description of the brain. It is a single view, from bottom to top,
or watch the prefrontal cortex make a moral judgment. We can of the human brain as we know it today—in all its beauty and
recognize the nerve patterns associated with amusement, empathy— complexity. Be amazed.
even the thrill of schadenfreude at the sight of an adversary suffering
defeat. More than just a map, the picture emerging from imaging
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INVESTIGATING THE BRAIN
THE BRAIN IS THE LAST OF THE HUMAN ORGANS TO GIVE UP ITS SECRETS. FOR A LONG TIME, PEOPLE
WERE NOT EVEN ABLE TO UNDERSTAND WHAT THE BRAIN IS FOR. THE DISCOVERY OF ITS ANATOMY,
FUNCTIONS, AND PROCESSES HAS BEEN A LONG AND SLOW JOURNEY ACROSS THE MILLENNIA, AS
HUMAN KNOWLEDGE ABOUT THIS MYSTERIOUS ORGAN HAS DEVELOPED AND ACCUMULATED.
EXPLORING THE BRAIN USING RATS
The brains of rats
The brain is particularly diffcult to investigate because its structures are very similar
are minute and its processes cannot be seen with the naked eye. The to human brains.
problem is compounded by the fact that its most interesting product, Until imaging
techniques were
consciousness, does not feel like a physical process, so there was no developed, the
obvious reason for our distant ancestors to associate it with the brain. only way scientists
were able to look
Nevertheless, over the centuries, philosophers and physicians built directly at brain
up an understanding of the brain and, in the last 25 years with the tissue was by using
advent of brain-imaging techniques, neuroscientists have created athned bortahinesr noof nra- ts
a detailed map of what was once an entirely mysterious territory. human animals.
387 BCE 1664
The Greek Oxford physiologist Thomas
philosopher Plato Willis publishes the frst brain
teaches at Athens; atlas, locating various
PAPYRUS he believes the functions in separate
brain is the seat of brain “modules.”
mental processes.
1700 BCE
Egyptian papyrus
desgcrivipetsio an c oafr ethfuel PLATO DRAWING THE BRAIN BRAIN ATLAS
brain, but Egyptians do
not rate this organ highly; 1543
unlike other organs, it is Andreas Vesalius, 1774 1848
4000 BCE removed and discarded 450 BCE a European physician, German physician Phineas Gage
Early Sumerian before mummifcation, Early Greeks begin publishes the frst Franz Anton Mesmer has his brain
writing notes the suggesting that it was not to recognize the “modern” anatomy, introduces “animal pierced by
euphoric effect considered to be of any brain as the seat of with detailed drawings magnetism,” later an iron rod
of poppy seeds. use in future incarnations. human sensation. of the human brain. called hypnosis. (see p.141).
4000 BCE 3000 BCE 2000 BCE 1000 BCE 1500 1600 1700 1800
2500 BCE 335 BCE 1649 1791
Trepanation (boring Greek philosopher French philosopher René Luigi Galvani, an
holes into the skull) is a Aristotle restates the Descartes describes the Italian physicist,
common surgical ancient belief that brain as a hydraulic system discovers the
procedure across many the heart is the that controls behavior. electrical basis
cultures, possibly used superior organ; the “Higher” mental functions of nervous activity
for relieving brain brain, a radiator to are generated by a by making frogs’
disorders such as stop the body from spiritual entity, however, legs twitch.
epilepsy, or for ritual overheating. which interacts with the
or spiritual reasons. RENÉ DESCARTES body via the pineal gland.
LUIGI GALVANI
1849
170 BCE German physicist
Roman physician Galen theorizes Hermann von
that human moods and Helmholtz measures
dispositions are due to the four the speed of nerve
“humors” (liquids that are held in conduction and
the brain’s ventricles). The idea subsequently
persists for more than 1,000 years. develops the idea
Galen’s anatomical descriptions, that perception
ARISTOTLE used by generations of physicians, depends upon
were based mainly on work “unconscious
TREPANNING on monkeys and pigs. GALEN AT WORK inferences.”
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