the human brain book

AN ILLUSTRATED GUIDE TO ITS STRUCTURE, FUNCTION, AND DISORDERS R I T A C A R T E RRITA CARTER R I TA C A R T E R HUMAN BRAIN T H E BOOK THE BOOK HUMAN BRAIN (c) 2011 Dorling Kindersley. All Rights Reserved. (c) 2011 Dorling Kindersley. All Rights Reserved. G>I686GI:G HJH6C6A9G>9<: B6GINCE6<: HI:K:E6G@:G 8DCHJAI6CIHEgd[Zhhdg8]g^h;g^i]! Egd[ZhhdgJiV;g^i]!VcY9g#BZaVc^ZH]jabVc HUMAN BRAIN THE BOOK (c) 2011 Dorling Kindersley. All Rights Reserved. 8DCI:CIH CDDG9>C6GNDG<6C >CK:HI><6I>C<I=:7G6>C A6C9B6G@H>CC:JGDH8>:C8: H86CC>C<I=:7G6>C 6?DJGC:NI=GDJ<=I=:7G6>C I=:7G6>C6C9I=:7D9N 7G6>C;JC8I>DC C:GKDJHHNHI:B I=:7G6>C6C9I=:C:GKDJH HNHI:B 7G6>CH>O:!:C:G<NJH:!6C9  EGDI:8I>DC :KDAJI>DC 7G6>C6C6IDBN 7G6>CHIGJ8IJG:H 7G6>CODC:H6C9E6GI>I>DCH CJ8A:>D;I=:7G6>C I=:I=6A6BJH!=NEDI=6A6BJH! 6C9E>IJ>I6GN<A6C9 I=:7G6>CHI:B6C98:G:7:AAJB + - &% &' &) (+ (- )% )' )) )- *% *' *+ *- +% +' I=:A>B7>8HNHI:B I=:8:G:7G6A8DGI:M 7G6>C8:AAH C:GK:>BEJAH:H I=:H:CH:H =DLL:H:CH:I=:LDGA9 I=::N: I=:K>HJ6A8DGI:M K>HJ6AE6I=L6NH K>HJ6AE:G8:EI>DC H::>C< I=::6G B6@>C<H:CH:D;HDJC9 I=:=:6G>C<EGD8:HH HB:AA E:G8:>K>C<HB:AA I6HI: IDJ8= I=:H>MI=H:CH: E6>CH><C6AH :ME:G>:C8>C<E6>C +) ++ +- ,' ,) ,+ ,- -% -' -) -+ .% .' .) .+ &%% &%' &%) &%+ H:C>DG:9>IDG Peter Frances H:C>DG6GI:9>IDG Maxine Lea london, new york, melbourne, munich, and dehli EGD?:8I:9>IDGH Nathan Joyce, Ruth O’Rourke, Miezan van Zyl 9:H><C:G Riccie Janus :9>IDG>6A6HH>HI6CI Elizabeth Munsey EGD?:8I6GI:9>IDGH Alison Gardner, Siân Thomas, Francis Wong :9>IDGH Salima Hirani, Katie John, Rebecca Warren JH:9>IDG Jill Hamilton (c) 2011 Dorling Kindersley. All Rights Reserved. BDK:B:CI6C9 8DCIGDA G:<JA6I>DC I=:C:JGD:C9D8G>C:HNHI:B EA6CC>C<6BDK:B:CI :M:8JI>C<6BDK:B:CI JC8DCH8>DJH68I>DC B>GGDGC:JGDCH :BDI>DCH6C9;::A>C<H I=::BDI>DC6A7G6>C 8DCH8>DJH:BDI>DC 9:H>G:6C96CI>8>E6I>DC I=:HD8>6A7G6>C H:M!ADK:!6C9HJGK>K6A :MEG:HH>DC I=:H:A;6C9DI=:GH I=:BDG6A7G6>C A6C<J6<:6C9 8DBBJC>86I>DC <:HIJG:H6C97D9NA6C<J6<: I=:DG><>CHD;A6C<J6<: I=:A6C<J6<:6G:6H 68DCK:GH6I>DC G:69>C<6C9LG>I>C< B:BDGN I=:EG>C8>EA:HD;B:BDGN I=:B:BDGNL:7 A6N>C<9DLC6B:BDGN G:86AA6C9G:8D<C>I>DC JCJHJ6AB:BDGN I=>C@>C< >CI:AA><:C8: 8G:6I>K>IN6C9=JBDG 7:A>:;6C9HJE:GHI>I>DC 8D<C>I>K:>AAJH>DCH 8DCH8>DJHC:HH L=6I>H8DCH8>DJHC:HH4 AD86I>C<8DCH8>DJHC:HH 6II:CI>DC6C98DCH8>DJHC:HH 6AI:G>C<8DCH8>DJHC:HH HA::E6C99G:6BH I>B: I=:H:A;6C98DCH8>DJHC:HH I=:>C9>K>9J6A7G6>C C6IJG:6C9CJGIJG: >C;AJ:C8>C<I=:7G6>C E:GHDC6A>IN JCJHJ6A7G6>CH 9:K:ADEB:CI6C9 6<>C< I=:9:K:ADE>C<7G6>C I=:6<>C<7G6>C I=:7G6>CD;I=:;JIJG: 9>H:6H:H6C9 9>HDG9:GH I=:9>HDG9:G:97G6>C 9>G:8IDGND;9>HDG9:GH <ADHH6GN >C9:M 68@CDLA:9<B:CIH &%- &&% &&' &&) &&+ &&- &'% &'' &') &'+ &'- &(% &(' &() &(+ &(- &)% &)' &)) &)+ &)- &*% &*' &*) &*+ &*- &+% &+' &+) &++ &+- &,% &,' &,) &,+ &,- &-% &-' &-) &-+ & &.% &.' &.) &.+ & '%% '%' '%+ '%- '&' '&) '&+Ä)& ')' ')- '*+ G:;:G:C8:EJ7A>H=:G Jonathan Metcalf 6GI9>G:8IDG Bryn Walls DVD minimum system requirements PC: Windows XP with service pack 2 or Windows Vista; Intel or AMD processor; soundcard; 24-bit color display; screen resolution 1024 x 768 Macintosh: Mac OS X v10.4; G4, G5, or Intel processor; soundcard; 24-bit color display; screen resolution 1024 x 768 Copyright © 2009 Dorling Kindersley Limited 09 10 11 12 10 9 8 7 6 5 4 3 2 1 All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), without prior written permission of the copyright owner and the above publisher of this book. Published in Great Britain by Dorling Kindersley Ltd. A catalog record for this book is available from the Library of Congress ISBN: 978-0-7566-5441-2 First American Edition, September 2009—175217 Published in the United States by DK Publishing, 375 Hudson Street, New York, New York 10014 Printed and bound in China by Hung Hing Discover more at www.dk.com E>8IJG:G:H:6G8=:G Liz Moore ?68@:I9:H><C:G Duncan Turner EJ7A>H=>C<B6C6<:G Liz Wheeler B6C6<>C<:9>IDG Sarah Larter H:C>DGB6C6<>C<6GI:9>IDG Phil Ormerod H:C>DGEGD9J8I>DC8DCIGDAA:G Inderjit Bhullar EGD9J8I>DC:9>IDG Tony Phipps 8G:6I>K:I:8=C>86AHJEEDGI Adam Brackenbury, John Goldsmid >C9:M:G Hilary Bird EGDD;G:69:G Polly Boyd The Human Brain Book provides information on a wide range of medical topics, and every effort has been made to ensure that the information in this book is accurate. The book is not a substitute for medical advice, however, and you are advised always to consult a doctor or other health professional on personal health matters. >AAJHIG6IDGH Medi-Mation, Peter Bull Art Studio DK books are available at special discounts when purchased in bulk for sales promootions, premiums, fund-raising, or educational use. For details, contact: DK Publishing Special Markets, 375 Hudson Street, New York 10014 or SpecialSales@dk.com. (c) 2011 Dorling Kindersley. All Rights Reserved. CDDG9>C6GNDG<6C The human brain is like nothing else. As organs go, it is not especially prepossessing—3lb (1.4kg) or so of rounded, corrugated flesh with a consistency somewhere between jelly and cold butter. It doesn’t 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 head and peered inside, you wouldn’t see much happening at all. H:6ID;8DCH8>DJHC:HH Given this, it is perhaps not surprising that for centuries the contents of our skulls were regarded as relatively unimportant. When they mummified their dead, the ancient Egyptians scooped out the brains and threw them away, yet carefully preserved the heart. The Ancient Greek philospher, Aristotle, thought the brain was a radiator for cooling the blood. René Descartes, the French scientist, gave it a little more respect, concluding that it was a sort of antenna by which the spirit might commune with the body. It is only now that the full wonder of the brain is being realized. The most basic function of the brain is to keep the rest of the body alive. Among your brain’s 100 billion neurons, some regulate your breathing, heartbeat, and blood pressure and others control hunger, thirst, sex drive, and sleep cycle. In addition to this, the brain generates the emotions, perceptions, and thoughts that guide your behavior. Then it directs and executes your actions. Finally, it is responsible for the conscious awareness of the mind itself. I=:9NC6B>87G6>C Until about 100 years ago, the only evidence that brain and mind were connected was obtained from “natural experiments”—accidents in which head injuries created aberrations in their victims’ behavior. Dedicated physicians mapped out areas of the cerebral landscape by observing the subjects of such experiments while they were alive— then matching their deficits to the damaged areas of their brains. It was slow work because the scientists had to wait for their subjects to die before they could look at the physiological evidence. As a result, until the early 20th century, all that was known about the physical basis of the mind could have been contained in a single volume. Since then, scientific and technological advances have fueled a neuroscientific revolution. Powerful microscopes made it possible to look in detail at the brain’s intricate anatomy. A growing understanding of electricity allowed the dynamics of the brain to be recognized and then, with the advent of electroencephalography (EEG), to be observed (c) 2011 Dorling Kindersley. All Rights Reserved.(c) 2011 Dorling Kindersley. All Rights Reserved. and measured. Finally, the arrival of functional brain imaging machines allowed scientists to look inside the living brain and see its mechanisms at work. In the last 20 years, positron emission tomography (PET), functional magnetic resonance imaging (fMRI), and, most recently, magnetic encephalography (MEG) have among them produced an ever more detailed map of the brain’s functions. A>B>IA:HHA6C9H86E: Today we can point to the circuitry that keeps our vital processes going, the cells that produce our neurotransmitters, the synapses where signals leap from cell to cell, and the nerve fibers that convey pain or move our limbs. We know how our sense organs turn light rays and sounds waves into electrical signals, and we can trace the routes they follow to the specialized areas of cortex that respond to them. We know that such stimuli are weighed, valued, and turned into emotions by the amygdala—a tiny nugget of tissue that punches well above its weight. We can see the hippocampus retrieve a memory, or watch the prefrontal cortex make a moral judgment. We can recognize the nerve patterns associated with amusement, empathy— even the thrill of schadenfreude at the sight of an adversary suffering defeat. More than just a map, the picture emerging from imaging studies reveals the brain to be an astonishingly complex, sensitive system in which each part affects almost every other. “High level” cognition performed by the frontal lobes, for instance, feeds back to affect sensory experience—so what we see when we look at an object is shaped by expectation as well as by the effect of light hitting the retina. Conversely, the brain’s most sophisticated products can depend on its lowliest mechanisms. Intellectual judgments, for example, are driven by the body reactions that we feel as emotions, and consciousness can be snuffed out by damage to the humble brainstem. To confuse things further, the system doesn’t stop at the neck but extends to the tips of your toes. Some would argue it even goes beyond—to encompass other minds with which it interacts. Neuroscientific investigation of the brain is very much a work in progress and no one knows what the finished picture will look like. It may be that the brain is so complicated that it can never understand itself entirely. So this book cannot be taken as a full description of the brain. It is a single view, from bottom to top, of the human brain as we know it today—in all its beauty and complexity. Be amazed. (c) 2011 Dorling Kindersley. All Rights Reserved.(c) 2011 Dorling Kindersley. All Rights Reserved. 8 JH>C<G6IH I]ZWgV^chd[gVih VgZkZgnh^b^aVgid ]jbVcWgV^ch#Jci^a ^bV\^c\iZX]c^fjZh lZgZYZkZadeZY! i]ZdcanlVn hX^Zci^hihlZgZVWaZ idadd`Y^gZXianVi WgV^ci^hhjZlVhWn jh^c\WgV^chd[gVih VcYdi]Zgcdc" ]jbVcVc^bVah# >CK:HI><6I>C<I=:7G6>C I=:7G6>C>HI=:A6HID;I=:=JB6CDG<6CHID<>K:JE>IHH:8G:IH#;DG6ADC<I>B:!E:DEA: L:G:CDI:K:C67A:IDJC9:GHI6C9L=6II=:7G6>C>H;DG#I=:9>H8DK:GND;>IH6C6IDBN! ;JC8I>DCH!6C9EGD8:HH:H=6H7::C6ADC<6C9HADL?DJGC:N68GDHHI=:B>AA:CC>6!6H =JB6C@CDLA:9<:67DJII=>HBNHI:G>DJHDG<6C=6H9:K:ADE:96C9688JBJA6I:9# >CK:HI><6I>C<I=:7G6>C :MEADG>C<I=:7G6>C The brain is particularly difficult to investigate because its structures are minute and its processes cannot be seen with the naked eye. The problem is compounded by the fact that its most interesting product, consciousness, does not feel like a physical process, so there was no obvious reason for our distant ancestors to associate it with the brain. Nevertheless, over the centuries, philosophers and physicians built up an understanding of the brain and, in the last 25 years with the advent of brain-imaging techniques, neuroscientists have created a detailed map of what was once an entirely mysterious territory. &,%%78: :\nei^VceVengjh \^kZhVXVgZ[ja YZhXg^ei^dcd[i]ZWgV^c! Wji:\nei^VchYdcdigViZ i]^hdg\Vc]^\]an0jca^`Z di]Zgdg\Vch!^i^hgZbdkZY VcYY^hXVgYZYWZ[dgZ bjbb^ÒXVi^dc!hj\\Zhi^c\ i]Vi^ilVhcdiXdch^YZgZY idWZd[VcnjhZ^c [jijgZ^cXVgcVi^dch# '*%%78: IgZeVcVi^dcWdg^c\ ]daZh^cidi]Zh`jaa^hV Xdbbdchjg\^XVa egdXZYjgZVXgdhhbVcn XjaijgZh!edhh^WanjhZY [dggZa^Zk^c\WgV^c Y^hdgYZghhjX]Vh Ze^aZehn!dg[dgg^ijVa dghe^g^ijVagZVhdch# )*%78: :Vgan<gZZ`hWZ\^cid gZXd\c^oZi]ZWgV^c Vhi]ZhZVid[ ]jbVchZchVi^dc# (-,78: I]Z<gZZ` e]^adhde]ZgEaVid iZVX]ZhVi6i]Zch0 ]ZWZa^ZkZhi]Z WgV^c^hi]ZhZVid[ bZciVaegdXZhhZh# ((*78: <gZZ`e]^adhde]Zg 6g^hidiaZgZhiViZhi]Z VcX^ZciWZa^Z[i]Vi i]Z]ZVgi^hi]Z hjeZg^dgdg\Vc0i]Z WgV^c!VgVY^Vidgid hidei]ZWdYn[gdb dkZg]ZVi^c\# &,%78: GdbVce]nh^X^Vc<VaZci]Zdg^oZh i]Vi]jbVcbddYhVcYY^hedh^i^dch VgZYjZidi]Z[djgÆ]jbdghÇ a^fj^Yhi]ViVgZ]ZaY^ci]ZWgV^cÉh kZcig^XaZh#I]Z^YZVeZgh^hih [dgbdgZi]Vc&!%%%nZVgh# <VaZcÉhVcVidb^XVaYZhXg^ei^dch! jhZYWn\ZcZgVi^dchd[e]nh^X^Vch! lZgZWVhZYbV^candcldg` dcbdc`ZnhVcYe^\h# &*)( 6cYgZVhKZhVa^jh! V:jgdeZVce]nh^X^Vc! ejWa^h]Zhi]ZÒghi ÆbdYZgcÇVcVidbn! l^i]YZiV^aZYYgVl^c\h d[i]Z]jbVcWgV^c# &+). ;gZcX]e]^adhde]ZgGZc 9ZhXVgiZhYZhXg^WZhi]Z WgV^cVhV]nYgVja^XhnhiZb i]ViXdcigdahWZ]Vk^dg# Æ=^\]ZgÇbZciVa[jcXi^dch VgZ\ZcZgViZYWnVhe^g^ijVa Zci^in!]dlZkZg!l]^X] ^ciZgVXihl^i]i]ZWdYnk^V i]Ze^cZVa\aVcY# &++) Dm[dgYe]nh^dad\^hiI]dbVh L^aa^hejWa^h]Zhi]ZÒghiWgV^c ViaVh!adXVi^c\kVg^djh [jcXi^dch^chZeVgViZWgV^c ÆbdYjaZh#Ç &,,) <ZgbVce]nh^X^Vc ;gVco6cidcBZhbZg ^cigdYjXZhÆVc^bVa bV\cZi^hb!ÇaViZg XVaaZY]necdh^h# &,.& Aj^\^<VakVc^!Vc >iVa^Vce]nh^X^hi! Y^hXdkZghi]Z ZaZXig^XVaWVh^h d[cZgkdjhVXi^k^in WnbV`^c\[gd\hÉ aZ\hil^iX]# )%%%78: &*%% &+%% &,%% &-%% )%%%78: :VganHjbZg^Vc lg^i^c\cdiZhi]Z Zje]dg^XZ[[ZXi d[edeenhZZYh# (%%%78: '%%%78: &%%%78: 9G6L>C<I=:7G6>C 7G6>C6IA6H E6ENGJH EA6ID AJ><><6AK6C> <6A:C6ILDG@ G:Cw9:H86GI:H 6G>HIDIA: IG:E6CC>C< &-)- E]^cZVh<V\Z ]Vh]^hWgV^c e^ZgXZYWn Vc^gdcgdY hZZe#&(.# &-). <ZgbVce]nh^X^hi =ZgbVcckdc =Zab]daiobZVhjgZh i]ZheZZYd[cZgkZ XdcYjXi^dcVcY hjWhZfjZcian YZkZadehi]Z^YZV i]VieZgXZei^dc YZeZcYhjedc ÆjcXdchX^djh ^c[ZgZcXZh#Ç (c) 2011 Dorling Kindersley. All Rights Reserved. 9 >CK:HI><6I>C<I=:7G6>C 8^gXV&.%% H^\bjcY;gZjYVWVcYdchVcZVgan XVgZZg^ccZjgdad\nidhijYn ehnX]dYncVb^Xh#I]ZhjXXZhhd[ ;gZjY^VcehnX]dVcVanh^hZXa^ehZY e]nh^dad\^XVaehnX]^Vign[dg]Va[ VXZcijgn# &.%+ HVci^V\d GVbcn8V_Va YZhXg^WZh]dl cZgkZXZaah Xdbbjc^XViZ# &.%+ 6ad^h6ao]Z^bZg YZhXg^WZh egZhZc^aZ YZ\ZcZgVi^dc hZZe#''(# &.%. @dgW^c^Vc7gdYbVccYZhXg^WZh *'Y^hXgZiZXdgi^XVaVgZVhWVhZY dccZjgVahigjXijgZ#I]ZhZVgZVh VgZhi^aajhZYidYVnhZZe#+,# &.') I]ZÒghiZaZXigdZcXZe]Vad\gVbh VgZegdYjXZYWn=Vch7Zg\Zg# &.() Edgij\jZhZcZjgdad\^hi:\VhBdc^o XVgg^Zhdjii]ZÒghiaZjXdidbn deZgVi^dchaViZg`cdlcVhadWdidb^Zh! hZZe#&&#=ZVahd^ckZciZYVc\^d\gVe]n! dcZd[i]ZÒghiiZX]c^fjZhi]ViVaadlZY hX^Zci^hihidbV`Z^bV\Zhd[i]ZWgV^c# &.*, L#EZcÒZaYVcY I#GVhbjhhZcYZk^hZ VbdidgVcYhZchdgn ]dbjcXjajh hZZee#&%VcY&%&# &.,%Ä-% 7gV^chXVcc^c\ ^hYZkZadeZY/ E:I!HE:8I! BG>!VcYB:< VaaZbZg\Z Yjg^c\i]^h YZXVYZ# &.,( I^bdi]n7a^hh VcYIZg_ZAdbd YZhXg^WZ adc\"iZgb ediZci^Vi^dc hZZe#&*+# & & Gd\ZgLdaXdii HeZggn^hVlVgYZY i]ZCdWZaEg^oZ[dg ]^hldg`dci]Z Y^[[ZgZci[jcXi^dch d[i]ZildWgV^c ]Zb^he]ZgZhhZZ ee#&&VcY& # & ( 7Zc_Vb^cA^WZi lg^iZhdci]Z i^b^c\d[ XdchX^djhkda^i^dc hZZe#&&# &.%% '%%% &-+'Ä,) 7gdXVVcYLZgc^X`Z hZZe#&%Y^hXdkZgi]Z ildbV^caVc\jV\Z VgZVhd[i]ZWgV^c# &-*% ;gVco?dhZe]<Vaa [djcYhe]gZcdad\n hZZe#&%!l]^X] Viig^WjiZhY^[[ZgZci eZghdcVa^inigV^ih idheZX^ÒXVgZVh d[i]Z]ZVY# C:GK:8:AAH >CGD9:CI =>EED86BEJH H><BJC9;G:J9 :<6HBDC>O :A:8IGD:C8:E=6AD<G6E=N C:GK:8:AAH :6GANB6<C:I>8>B6<>C< 8DGI>86AB6E & HVci^V\dGVbcn8V_VaegdedhZh i]VicZgkZXZaahVgZ^cYZeZcYZci ZaZbZcihVcYi]ZWVh^Xjc^ihd[ i]ZWgV^c^cI]ZCZjgdc9dXig^cZ# =Zl^chi]ZCdWZaEg^oZ^c&.%+# &.*( 7gZcYVB^acZg YZhXg^WZh eVi^Zci=B hZZe#&*,! l]dhj[[Zgh bZbdgn adhhV[iZg ]^eedXVbeVa hjg\Zgn# &.&. >g^h]cZjgdad\^hi <dgYdc Bdg\Vc=dabZh adXVa^oZhk^h^dc idi]Zhig^ViZ XdgiZmi]Z eg^bVgnk^hjVa XdgiZm# &-*. 8]VgaZh 9Vgl^c ejWa^h]Zh Dci]Z Dg^\^cd[ HeZX^Zh# &-,) 8VgaLZgc^X`Z ejWa^h]Zhdc Ve]Vh^VaVc\jV\Z Y^hdgYZghV[iZg WgV^cYVbV\Z# &.&) 7g^i^h]e]nh^dad\^hi =Zcgn=VaaZii9VaZ ^hdaViZhVXZinaX]da^cZ! i]ZÒghid[i]ZcZjgd" igVchb^iiZghhZZe#,(id WZY^hXdkZgZY#=Zl^ch i]ZCdWZaEg^oZ^c&.(+# & ' B^ggdgcZjgdch VgZY^hXdkZgZY Wn<^VXdbd G^oodaVii^ ^cEVgbVhZZ ee#&&VcY&'%Ä'&# '%%. :meadgVi^dcXdci^cjZh! l^i]gZhZVgX]iZVbh Xdci^cjdjhanbV`^c\ hiZehidlVgY\gZViZg jcYZghiVcY^c\# HX^Zci^hihlZgZjcVWaZidÒcYdjibjX]VWdjii]Zldg`^c\h d[i]ZWgV^cjci^agZaVi^kZangZXZcian#I]ZdcanlVni]Zn lZgZVWaZidbViX][jcXi^dchhjX]Vhh^\]i!Zbdi^dc!dg heZZX]idi]ZadXVi^dch^ci]ZWgV^c^cl]^X]i]ZnVgZ XdcigdaaZYlVhidÒcYVeZghdc^cl]dbV[VXjainlVh Y^hijgWZYYjZid^c_jgn!VcYi]ZclV^ijci^ai]ZnlZgZYZVY ^cdgYZgidadd`Vii]ZadXVi^dcVcYZmiZcid[i]ZWgV^c YVbV\Z#Di]Zgl^hZ!hX^Zci^hihXdjaYdcan\jZhhVil]VilVh ]VeeZc^c\idi]ZWgV^cWndWhZgk^c\eZdeaZÉhWZ]Vk^dg# IdYVn!bdYZgc^bV\^c\iZX]c^fjZhhjX]Vh[jcXi^dcVaBG> VcY::<hZZe#&'VaadlcZjgdhX^Zci^hihidhZZi]ZZaZXig^XVa VXi^k^in^ci]ZWgV^cVhVeZghdcXVgg^ZhdjikVg^djhiVh`hdg i]dj\]iegdXZhhZh#I]^hVaadlhi]Zbida^c`ineZhd[VXi^dch! Zbdi^dch!VcYhddc!idheZX^ÒXineZhd[VXi^k^in^ci]Z WgV^c#I]Z[gZZYdbiddWhZgkZi]ZWgV^ci]Vi^bV\^c\ iZX]c^fjZh]VkZV[[dgYZY]VhVaadlZY[dgVcZmeadh^dcd[ `cdlaZY\Zl^i]^ccZjgdhX^ZcXZ!VcY]VhYZZeZcZYdjg jcYZghiVcY^c\d[i]ZWgV^cVcY]dl^ildg`h# I=:69K:CID;>B6<>C<I:8=C>FJ:H B6<C:I>8G:HDC6C8:>B6<>C< 7gV^chXVchXVcgZkZVaYVbV\ZYi^hhjZÄ i]ZgZYVgZV^ci]ZBG>hXVcVWdkZ ^cY^XViZhYVbV\ZXVjhZYWnVhigd`Z# :A:8IGD9:H CZjgVaVXi^k^inXVc WZbZVhjgZYWn ViiVX]^c\ZaZXigdYZh idi]ZhXVae#I]ZhZ e^X`jeZaZXig^XVa VXi^k^in^ci]ZWgV^c VcYigVch[dgb^i^cid VY^\^iVagZXdgY# :aZXigdYZ ÆXVeÇ &-,( >iVa^VchX^Zci^hi 8Vb^aad<da\^ ejWa^h]Zhi]Zh^akZg c^igViZbZi]dY! bV`^c\^iedhh^WaZid hZZcZgkZh^ci]Z^g Zci^gZin#=Zl^chi]Z CdWZaEg^oZ^c&.%+# (c) 2011 Dorling Kindersley. All Rights Reserved. [...]... areas of the brain The first detailed maps of human brain function were made by Canadian brain surgeon Wilder Penfield He worked with patients undergoing surgery to control epilepsy While the brain was exposed, and the patient conscious, Penfield probed the cortex with an electrode and noted the responses of the patient as he touched each part Penfield’s work was the first to reveal the role of the temporal... its brain In another, he put a device in the brain of a chimp that was bullying its mate He put the control in the cage where the victim chimp used it to “turn off” the bully’s bad behavior (c) 2011 Dorling Kindersley All Rights Reserved The first lobotomies were performed in the 1890s, but they only took off in the 1930s when the Portuguese neurosurgeon Egas Moniz found that cutting the nerves from the. .. the nineteenth century, much was learned about the structure of the brain by removing it from the body after death Knowledge of the workings of the living human brain could only be gained by studying people with damaged brains, for example Phineas Gage (see p.139), but the precise location of this damage could not be known while the patient was still alive Everything changed with the invention of brain. .. the end of the twentieth century In the following pages, we shall undertake a journey through the brain of a healthy, 55-year-old man revealed by magnetic resonance imaging (MRI) In these images, we can see the many components of the brain We are starting to understand the function of some of these, but we are only at the very beginning of this journey of understanding The captions that accompany the. .. indicate the most likely function of various brain regions But these regions often have many functions, and these functions depend upon interactions with other brain regions Most structures in the brain are paired, with identical counterparts in the left and right hemispheres, so structures identified in one hemisphere are mirrored in the opposite one The scans themselves have been colored, so that the cerebrum... to produce multiple “slices” of the body It allows you to see normally obscured body tissues, such as the inside of the brain, from any angle or level, with the delicate inner structures thrown into clear relief Artificial coloring of the areas further distinguishes one part from another CT scans are purely structural: they show the form of the organ but not how it works They are very good at showing... the neural activity in the monkey’s brain that sparked up in response to the sight was identical to the activity that occurred when the monkey made the action itself Mirror neurons are thought by some to be the basis of theory of mind, mimicry, and empathy 11 (c) 2011 Dorling Kindersley All Rights Reserved The structure of the brain is well known, but until recently the way it created thoughts, emotions,... for the rest of his life The tragic accident demonstrated the crucial role of the hippocampus in recall Neurobiologist Roger Sperry conducted the split -brain experiments (see p.198) on people whose brain hemispheres were surgically separated in the course of treatment for epilepsy They showed that, under certain conditions, each hemisphere could hold different thoughts and intentions This raised the. .. a person’s brain making a decision, we see that apparently rational decisions are driven by the emotional brain Imaging the brains of master chess players shows why expertise depends on practice Watching the brain of a person seeing a frightened face shows that emotion is contagious 12 The brain looks very different according to how it is viewed Computed tomography (CT) imaging combines the use of... computerized image The brain is scanned at a rapid rate (typically once every 2–3 seconds) to produce “slices” similar to those in CT scans Increases in neural activity cause changes in the blood flow, which alter the amount of oxygen in the area, producing a change in the magnetic signal Functional MRI (fMRI) involves showing differing levels of electrical activity in the brain, overlaid on the anatomical . antenna by which the spirit might commune with the body. It is only now that the full wonder of the brain is being realized. The most basic function of the brain is to keep the rest of the body. of the cerebral landscape by observing the subjects of such experiments while they were alive— then matching their deficits to the damaged areas of their brains. It was slow work because the. Reserved. 15 6?DJGC:NI=GDJ<=I=:7G6>C I=:7G6>C>HI=:BDHI8DBEA:MDG<6C>CI=:7D9N6C9>HEGD767ANI=:BDHI8DBEA:MHNHI:B @CDLCID=JB6C@>C9#DJG7G6>C8DCI6>CH7>AA>DCHD;C:JGDCHI=6I6G:8DCHI6CIANH:C9>C< H><C6AHID:68=DI=:G!6C9>I>HI=>HH><C6A>C<I=6I8G:6I:HDJGB>C9H#L>I=I=:=:AED; BD9:GCH86CC>C<I:8=CDAD<N!L:CDL@CDL67DJI7G6>CHIGJ8IJG:>C<G:6I9:I6>A# 6?DJGC:NI=GDJ<=I=:7G6>C In the nineteenth century, much was learned about the structure of the brain by removing it from the body after death. Knowledge of the workings of the living human brain could only