Preface to the fourth edition The motivation for writing this book came out of my experiences of teaching cognitive neuroscience.When asked by students which book they should buy, I felt that none of the existing books would satisfactorily meet their needs. Other books in the market were variously too encyclopedic,too advanced or not up to date,or gave short shrift to explaining the methods of the field.My brief for writing this textbook was to provide a text that presents key ideas and findings but is not too long.that is up to date and that considers both method and theory.I hope that it will be useful to both lecturers and students. In writing a book on cognitive neuroscience I had to make a decision as to how much would be“cognitive'”and how much would be“neuroscience. In my opinion,the theoretical underpinnings of cognitive neuroscience lie within the cognitive psychology tradition.Some of the most elegant studies using methods such as fMRI and TMS have been motivated by previous research in cognitive psychology and neuropsychology.The ultimate aim of cognitive neuroscience is to provide a brain-based account of cognition.and so the methods of cognitive neuroscience must necessarily speak to some aspect of brain function.However.I believe that cognitive neuroscience has much to learn from cognitive psychology in terms of which theoretically interesting questions to ask. In Chapter 1.I discuss the current status of cognitive neuroscience as I see it.Some of the topics raised in this chapter are directly aimed at other researchers in the field who are skeptical about the merits of the newer methodologies.i suspect that students who are new to the field will approach the topic with oper mindedness rather than skepticism,but I hope that they will ne ertheless be able to gain something from this debate. Chapter 2 is intended primarily as a reference source that can be referred back to.It is deliberately pitched at a need-to-know level. Chapters3to 5 des ibe in detail the methods of c The aim ognitive neuroscience i h nd.in d if the which the field is t ents fully understand them opin ed.I also hope that these hapters will he
Preface to the fourth edition The motivation for writing this book came out of my experiences of teaching cognitive neuroscience. When asked by students which book they should buy, I felt that none of the existing books would satisfactorily meet their needs. Other books in the market were variously too encyclopedic, too advanced or not up to date, or gave short shrift to explaining the methods of the field. My brief for writing this textbook was to provide a text that presents key ideas and findings but is not too long, that is up to date and that considers both method and theory. I hope that it will be useful to both lecturers and students. In writing a book on cognitive neuroscience I had to make a decision as to how much would be “cognitive” and how much would be “neuroscience.” In my opinion, the theoretical underpinnings of cognitive neuroscience lie within the cognitive psychology tradition. Some of the most elegant studies using methods such as fMRI and TMS have been motivated by previous research in cognitive psychology and neuropsychology. The ultimate aim of cognitive neuroscience is to provide a brain-based account of cognition, and so the methods of cognitive neuroscience must necessarily speak to some aspect of brain function. However, I believe that cognitive neuroscience has much to learn from cognitive psychology in terms of which theoretically interesting questions to ask. In Chapter 1, I discuss the current status of cognitive neuroscience as I see it. Some of the topics raised in this chapter are directly aimed at other researchers in the field who are skeptical about the merits of the newer methodologies. I suspect that students who are new to the field will approach the topic with open-mindedness rather than skepticism, but I hope that they will nevertheless be able to gain something from this debate. Chapter 2 is intended primarily as a reference source that can be referred back to. It is deliberately pitched at a need-to-know level. Chapters 3 to 5 describe in detail the methods of cognitive neuroscience. The aim of an undergraduate course in cognitive neuroscience is presumably to enable students to critically evaluate the field and, in my opinion, this can only be achieved if the students fully understand the limitations of the methods on which the field is based. I also hope that these chapters will be
xi PREFACE TO THE FOURTH EDITION of use to researchers who are starting out in the field.This fourth edition has been updated to include the latest research tools (such as tES.transcranial electrical stimulation)and the latest research methodology(such as multi- voxel pattern analysis.MVPA.in fMRI research). Chapters 6 to 16 outline the main theories and findings in the field.I hope that they convey something of the excitement and ontimism that cu exists.This fourth edition r sents a substantial update.The order of the on (as it deals with general issues relating to brain structure and function).These chapters were also extensively updated to take into account the pid changes in this field.notably the links with genetic methods and cor anectomics Vision and consecutive ch apters (Chap s 7 and 8).which link well to The cha on at entio d added for the first time ula (Chapte magnetoencepl Ch nal hear-1 (Chapter4, visual imagery (C parieta oDbioiogiceal orimotor transformatic on (Chapte and production (Chapte dyslexia (Chapter 13)and the neuroscience of racia ses(Chapter 16). In add o.hve crayof coiv (www.testableorg/ward)with test Rezlescu.Within the textbook,we provide more guidance to web resources via new feature the text,as well as via our dedicated webpage (www.routledge.com/cw/ward). Jamie Ward jamiew@sussex.ac.uk Brighton,UK,March 2019
xii PREFACE TO THE FOURTH EDITION of use to researchers who are starting out in the field. This fourth edition has been updated to include the latest research tools (such as tES, transcranial electrical stimulation) and the latest research methodology (such as multivoxel pattern analysis, MVPA, in fMRI research). Chapters 6 to 16 outline the main theories and findings in the field. I hope that they convey something of the excitement and optimism that currently exists. This fourth edition represents a substantial update. The order of the chapters has been changed to bring development much earlier on (as it deals with general issues relating to brain structure and function). These chapters were also extensively updated to take into account the rapid changes in this field, notably the links with genetic methods and connectomics. Vision and hearing are now consecutive chapters (Chapters 7 and 8), which link well to the following chapters on attention and action. The following topics have either been added for the first time or extensively updated: network versus modular approaches (Chapter 1), magnetoencephalography (MEG) (Chapter 3), functional near-infrared spectroscopy (fNIRS) (Chapter 4), visual imagery (Chapter 7), parietal lobe mechanisms of sensorimotor transformation (Chapter 10), recent neurobiological models of speech perception and production (Chapter 12), developmental dyslexia (Chapter 13) and the neuroscience of racial biases (Chapter 16). In addition, we have created a demonstration library of cognitive tests (www.testable.org/ward) with thanks to Constantin Rezlescu. Within the textbook, we provide more guidance to web resources via new feature boxes in the text, as well as via our dedicated webpage (www.routledge.com/cw/ward). Jamie Ward jamiew@sussex.ac.uk Brighton, UK, March 2019
CHAPTER 1 Introducing cognitive neuroscience CONTENTS Cognitive neuroscience in historical perspective 2 Does cognitive psychology need the brain? 10 Does neuroscience need cognitive psychology? 12 From modules to networks 13 Summary and key points of the chapter 16 Example essay questions 16 Recommended further reading 17 Between 1928 and 1947.Wilder Penfield and colleagues carried out a series of remarkable experiments on over 400 living human brains(Penfield Rasmussen,1950).The patients in question were undergoing brain surgery for epilepsy.To identify and spare regions of the brain involved in movement and sensation,Penfield electrically stimulated regions of the cortex while the patient was still conscious.The procedure was not painful (the surface of the brain does not contain pain receptors),but the patients did report some fascinating experiences.When stimulating the occipital lobe one patient reported,"a star came down toward my nose."Upon stimulating a region near the central sulcus,another patient commented,"those fingers and my thumb gave a jump."After temporal lobe stimulation,another patient claimed,"I heard the music again;it is like the radio."She was later able to recall the tune she heard and was absolutely convinced that there must have been a radio in the operating theatre.Of course,the patients had no idea when the electrical stimulation was being applied-they couldn't physically feel it or see it.As far as they were concerned,an electrical stimulation applied to the brain felt pretty much like a mental/cognitive event. This book tells the emerging story of how mental processes such as thoughts,memories and perceptions are organized and implemented by the
Between 1928 and 1947, Wilder Penfield and colleagues carried out a series of remarkable experiments on over 400 living human brains (Penfield & Rasmussen, 1950). The patients in question were undergoing brain surgery for epilepsy. To identify and spare regions of the brain involved in movement and sensation, Penfield electrically stimulated regions of the cortex while the patient was still conscious. The procedure was not painful (the surface of the brain does not contain pain receptors), but the patients did report some fascinating experiences. When stimulating the occipital lobe one patient reported, “a star came down toward my nose.” Upon stimulating a region near the central sulcus, another patient commented, “those fingers and my thumb gave a jump.” After temporal lobe stimulation, another patient claimed, “I heard the music again; it is like the radio.” She was later able to recall the tune she heard and was absolutely convinced that there must have been a radio in the operating theatre. Of course, the patients had no idea when the electrical stimulation was being applied—they couldn’t physically feel it or see it. As far as they were concerned, an electrical stimulation applied to the brain felt pretty much like a mental/cognitive event. This book tells the emerging story of how mental processes such as thoughts, memories and perceptions are organized and implemented by the CONTENTS Cognitive neuroscience in historical perspective 2 Does cognitive psychology need the brain? 10 Does neuroscience need cognitive psychology? 12 From modules to networks 13 Summary and key points of the chapter 16 Example essay questions 16 Recommended further reading 17 CHAPTER 1 Introducing cognitive neuroscience
2 THE STUDENTS GUIDE TO COGNITIVE NEUROSCIENCE FIGURE1.1:A timeline for ofmethods 1800 Phrenologists put forward their localizationist manifesto from 1820 phrenology to present day. 1840 First nerve cell described (purkinje,1837) 1860 -Broca(181)publishes localization 1880 1900 EEG 1920 AoSaStrl9ggeuenableshgecarecordiag 1940 1960 CT(Hounsfield,1973)and MRI (Lauterbur,1973)imaging developed 1980 -in vivo blood flow measured in humans,enabling PET(Reivich et al,1979 First study of TMS reported (Barker et al 1985) 2000 BOLD re 2010 ions of the brair brain.It is also concerned with how it is possible to study the mind and brain. and how we know what we know.The term cognition collectively refers to e月a a variety of higher mental processes such as thinking.perceiving,imagining. ONLINE RESOURCES speaking,acting and planning.Cognitive neuroscience is a bridging To discover more discipline between cognitive science and cognitive psychology.on the one abgutwncerPenield hand.and biology and neuroscience.on the other.It has emerged as a distinct enterprise only ently and has been driven by methodological advances that rwatch the enable the study of the human brain safely in the laboratory (see Figure 1.1). videos found on the It is perhaps not too surprising that earlier methods,such as direct electrical www.rutedge.com/ stimulation of the brain.failed to enter into the mainstream of research. cw/ward). This chapter begins by placing a number of philosophical and scientific aches to the ind and bra in a historical n ctive The than nd stud ents with lar ine KEY TERMS s might to ad tr ore dee 8.2015 vides basic iew of the methods A variety of higher A parison of the mental processes such ethods is ers3to 5.Finally,the chapter att as think th of th ing.perceiving. e cognitive ne acting and planning COGNITIVE NEUROSCIENCE IN HISTORICAL PERSPECTIVE brain-based mechanisms Philosophical approaches to mind and brain 5心sopheras心心o，遥beeninter地how the brais brain)can give rise to our as b e can he the r
2 THE STUDENT’S GUIDE TO COGNITIVE NEUROSCIENCE brain. It is also concerned with how it is possible to study the mind and brain, and how we know what we know. The term cognition collectively refers to a variety of higher mental processes such as thinking, perceiving, imagining, speaking, acting and planning. Cognitive neuroscience is a bridging discipline between cognitive science and cognitive psychology, on the one hand, and biology and neuroscience, on the other. It has emerged as a distinct enterprise only recently and has been driven by methodological advances that enable the study of the human brain safely in the laboratory (see Figure 1.1). It is perhaps not too surprising that earlier methods, such as direct electrical stimulation of the brain, failed to enter into the mainstream of research. This chapter begins by placing a number of philosophical and scientific approaches to the mind and brain in a historical perspective. The coverage is selective rather than exhaustive, and students with a particular interest in these issues might want to read more deeply elsewhere (Wickens, 2015). The chapter then provides a basic overview of the current methods used in cognitive neuroscience. A more detailed analysis and comparison of the different methods is provided in Chapters 3 to 5. Finally, the chapter attempts to address some of the criticisms of the cognitive neuroscience approach that have been articulated and outlines how it can move forward. COGNITIVE NEUROSCIENCE IN HISTORICAL PERSPECTIVE Philosophical approaches to mind and brain Philosophers, as well as scientists, have long been interested in how the brain can create our mental world. How is it that a physical substance can give rise to our sensations, thoughts and emotions? This has been termed the mind–body problem, although it should more properly be called the mind– brain problem, because it is now agreed that the brain is the key part of FIGURE 1.1: A timeline for the development of methods and findings relevant to cognitive neuroscience, from phrenology to present day. KEY TERMS Cognition A variety of higher mental processes such as thinking, perceiving, imagining, speaking, acting and planning. Cognitive neuroscience Aims to explain cognitive processes in terms of brain-based mechanisms. Mind–body problem The problem of how a physical substance (the brain) can give rise to our sensations, thoughts and emotions (our mind). ONLINE RESOURCES To discover more about Wilder Penfield and his pioneering research, watch the videos found on the companion website (www.routledge.com/ cw/ward). Phrenologists put forward their localizationist manifesto First nerve cell described (purkinje, 1837) Broca (1861) publishes paper on language localization Applying electrical currents to dog cortex causes movement (Fritsch & Hitzig, 1870) EEG developed as a research tool (Berger, 1929) Action potential discovered, enables single-cell recording (Hodgkin & Huxley, 1939) Cognitive psychology emerges (influential publications by Broadbent, Chomsky, Miller and others) CT (Hounsfield, 1973) and MRI (Lauterbur, 1973) imaging developed in vivo blood flow measured in humans, enabling PET (Reivich et al., 1979) First study of TMS reported (Barker et al., 1985) Attempt to map all major connections of the brain (Human Connectome Project) BOLD response reported enabling fMRI development (Ogawa et al., 1990) 1800 1820 1840 1860 1880 1900 1920 1940 1960 1980 2000 2010
INTRODUCING COGNITIVE NEUROSCIENCE 3 mind and brain a made KEY TERMS up of diffe even though they Dualism 6 m he mos mous proponent Descartes(1596 Descartes believed The belief that mind hat the min vas non-phys nd immortal whereas the body was physical and mortal.He suggested ha they interact in the pineal gland,which lies at the center of the brain and is now considered part of the endocrine system.According to Descartes stimulation of the sense organs would cause vibrations in the body/brain that Dual-aspect theory and would be picked up in the pineal gland,and this would create a non-physical brain are two s of sense of awareness.There is little hope for cognitive neuroscience if dualism is description of the same true because the methods of physical and biological sciences cannot tap into thing. the non-physical domain (if such a thing were to exist). Even in Descartes'time,there were critics of his position.One can The helief that mind- identify a number of broad approaches to the mind-body problem that still based concepts will have a contemporary resonance.Spinoza(1632-1677)argued that mind and brain were two different levels of explanation for the same thing.but not two different kinds of thing.This has been termed dual-aspect theory and it remains popular with some current researchers in the field(Velmans,2000). An analogy can be drawn to wave-particle duality in physics,in which the same entity(e.g.,an electron)can be described both as a wave and as a particle. An alternative approach to the mind-body problem that is endorsed by many contemporary thinkers is reductionism(Churchland,1995;Crick, 1994).This position states that,although cognitive mind-based concepts (e.g. emotions,memories,attention)are currently useful for scientific exploration. they will eventually be replaced by purely biological constructs (e.g.. patterns of neuronal firings neurotransmitter release) As such,psychology will eventually reduce to biology as we learn more and more about the brain. Advocates of this approach note that there are many historical precedents in which scientific constructs are abandoned when a better explanation is found. In the seventeenth century scientists believed that flammable materials contained a substance called phlogiston.which was released when burned. This is similar to classical notions that fire was a basic element along with water. air and earth eventually this construc of how chemicals with replaced by T of b ning bec with ting eaction that mind-ba arict status as phlogiston n future theory of Those aspe ct th ory over ducti poin tha would s an emo otion eve were its the usef ess of cognitive,min 1.h be fully replaced Scientific approaches to mind and brain Our understanding of the brain emerged historically late,largely in the th C)note e to bod was gre intellectu such as humans
Introducing cognitive neuroscience 3 the body for cognition. One position is that the mind and brain are made up of different kinds of substance, even though they may interact. This is known as dualism, and the most famous proponent of this idea was René Descartes (1596–1650). Descartes believed that the mind was non-physical and immortal whereas the body was physical and mortal. He suggested that they interact in the pineal gland, which lies at the center of the brain and is now considered part of the endocrine system. According to Descartes, stimulation of the sense organs would cause vibrations in the body/brain that would be picked up in the pineal gland, and this would create a non-physical sense of awareness. There is little hope for cognitive neuroscience if dualism is true because the methods of physical and biological sciences cannot tap into the non-physical domain (if such a thing were to exist). Even in Descartes’ time, there were critics of his position. One can identify a number of broad approaches to the mind–body problem that still have a contemporary resonance. Spinoza (1632–1677) argued that mind and brain were two different levels of explanation for the same thing, but not two different kinds of thing. This has been termed dual-aspect theory and it remains popular with some current researchers in the field (Velmans, 2000). An analogy can be drawn to wave–particle duality in physics, in which the same entity (e.g., an electron) can be described both as a wave and as a particle. An alternative approach to the mind–body problem that is endorsed by many contemporary thinkers is reductionism (Churchland, 1995; Crick, 1994). This position states that, although cognitive, mind-based concepts (e.g., emotions, memories, attention) are currently useful for scientific exploration, they will eventually be replaced by purely biological constructs (e.g., patterns of neuronal firings, neurotransmitter release). As such, psychology will eventually reduce to biology as we learn more and more about the brain. Advocates of this approach note that there are many historical precedents in which scientific constructs are abandoned when a better explanation is found. In the seventeenth century, scientists believed that flammable materials contained a substance, called phlogiston, which was released when burned. This is similar to classical notions that fire was a basic element along with water, air and earth. Eventually, this construct was replaced by an understanding of how chemicals combine with oxygen. The process of burning became just one example (along with rusting) of this particular chemical reaction. Reductionists believe that mind-based concepts, and conscious experiences in particular, will have the same status as phlogiston in a future theory of the brain. Those who favor dual-aspect theory over reductionism point out that an emotion would still feel like an emotion even if we were to fully understand its neural basis and, as such, the usefulness of cognitive, mind-based concepts will never be fully replaced. Scientific approaches to mind and brain Our understanding of the brain emerged historically late, largely in the nineteenth century, although some important insights were gained during classical times. Aristotle (384–322 bc) noted that the ratio of brain size to body size was greatest in more intellectually advanced species, such as humans. Unfortunately, he made the error of claiming that cognition was a product of KEY TERMS Dualism The belief that mind and brain are made up of different kinds of substance. Dual-aspect theory The belief that mind and brain are two levels of description of the same thing. Reductionism The belief that mindbased concepts will eventually be replaced by neuroscientific concepts