Introducing Neuropsychology

2nd Edition

John Stirling, Rebecca Elliott

• Publisher: Psychology Press
• Year: 2010
• ISBN:
  9781136897085
• Edition: 2
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

Introducing Neuropsychology, Second Edition investigates the functions of the brain and explores the relationships between brain systems and human behaviour. The material is presented in a jargon-free, easy to understand manner and aims to guide students new to the field through current areas of research.

Following a brief history of the discipline and a description of methods in neuropsychology, the remaining chapters review traditional and recent research findings. Both cognitive and clinical aspects of neuropsychology are addressed to illustrate the advances scientists are making (on many fronts) in their quest to understand brain - behaviour relationships in both normal and disturbed functioning. The rapid developments in neuropsychology and cognitive neuroscience resulting from traditional research methods as well as new brain-imaging techniques are presented in a clear and straightforward way. Each chapter has been fully revised and updated and new brain-imaging data are incorporated throughout, especially in the later chapters on Emotion and Motivation, and Executive Functions. As in the first edition, key topics are dealt with in separate focus boxes, and "interim comment" sections allow the reader a chance to "take stock" at regular intervals.

The book assumes no particular expertise on the reader's part in either psychology or brain physiology. Thus, it will be of great interest not only to those studying neuropsychology and cognitive neuroscience, but also to medical and nursing students, and indeed anyone who is interested in learning about recent progress in understanding brain–behaviour relationships.

CHAPTER 1
The foundations of neuropsychology

CONTENTS

Introduction 3

Neuropsychology as a distinct discipline 3

The (re)emergence of neuropsychology 12

Chapter summary 19

INTRODUCTION

We take the view that a proper understanding of the current status of neuropsychology cannot be formed without at least a rudimentary appreciation of its origins. Thus, in this chapter we offer a brief history of the beginnings of scientific research into the brain, and we introduce some of the theories (and debates) that have surfaced as our understanding of the relationship between structure and functions has developed. We describe some discoveries that led to the development of the so-called “brain hypothesis”, a concept that is central to neuropsychology (if not to psychology as a whole). We then introduce the “localisation of function” debate, which has rumbled on from its origins in the work of the 19th-century neuroanatomists, and continues to influence the distinct approaches and methodologies of clinical and cognitive neuropsychologists that we describe towards the end of the chapter. Fodor’s concept of modularity (of mind: he is a philosopher rather than a researcher) is introduced and re-assessed in light of recent findings. Its current status is considered, by way of illustration, in relation to the neuroanatomy and connectivity of a little-known region of cortex called the precuneus (Cavanna & Trimble, 2006).

NEUROPSYCHOLOGY AS A DISTINCT DISCIPLINE

Neuropsychology is a bridging discipline that draws on material from neurology, cognitive psychology, and even psychiatry. However, its principal aim is to try to understand the operation of psychological processes in relation to brain structures and systems. It is the oldest branch of scientific psychology and it retains a degree of distinctiveness that distinguishes it from other related areas. It has, for example, historically relied on small N or even single-case study designs, a tradition that continues to this day. Like cognitive neuroscience (see preface to this edition) it embraces the concept of converging operations (in which research findings from different sources and even different levels of inquiry are “used” to inform a particular debate). But unlike cognitive neuroscience, we should expect some fairly direct reference to human behaviour, and also unlike cognitive neuroscience, the brain itself may seem quite marginalised from the debate. Brain structures barely merit mention in Ellis and Young’s classic text Human cognitive neuropsychology (1996), for example. (See also Coltheart, 2001, whose ideas are summarised later in this chapter.)

The term “neuropsychology” was used as a subtitle in Donald Hebb’s influential book The organisation of behaviour: A neuropsychological theory, published in 1949, although the term itself was not defined. With the demise of behaviourism (terms in bold type in the text indicate that the term is included in the Glossary section at the end of the book) and renewed interest in cognitive processes in the 1950s and 1960s, the term appeared with increasing frequency, although its definition remained vague and it was used in different senses by different people. Although, as you will see, researchers had been interested in the effects of brain damage and disease on behaviour for many years, it was arguably some time after behaviourism’s fall from grace that neuropsychology came to develop a distinct identity within psychology, and its parameters were further clarified by the publication of the first edition of Kolb and Whishaw’s Fundamentals of human neuropsychology and Lezak’s Neuropsychological assessment in 1980 and 1983 respectively.

It would be misleading for us to suggest that, following its protracted birth, neuropsychology has emerged as an entirely unified discipline. In reality there remain different emphases among practitioners and researchers, which broadly divide into two domains: those of clinical and cognitive neuropsychology. At the risk of oversimplifying the distinction, the former tends to focus on the effects of brain damage/disease on psychological processes such as memory, language, and attention, and often has a clinical remit for assessment and even treatment. Conversely, the latter tries to understand impairments to psychological processes in terms of disruptions to the information-processing elements involved. In other words, the clinical approach goes from the damaged brain to psychological dysfunction and its remediation, whereas the cognitive approach goes from psychological dysfunction to hypothetical models about the individual stages of information processing that could explain such dysfunctions, which may (or may not) then be “mapped” onto various brain regions. This division has led to quite heated debates among neuropsychologists about, for instance, the merits/short-comings of single-case versus group research designs, and the extent to which cases of localised brain damage can ever definitively be used as evidence in support of functional localisation. (We take up each of these points in the following chapters. However, see the special issue of the journal Cognitive Neuropsychology, 2004, vol 21, for a flavour of the arguments.)

Incidentally, a glimpse at the chapter titles in this book might suggest to the reader that we too have chosen to take a cognitive approach to neuropsychology. However, this is not the case, and it is our hope that you will see that both approaches have much to offer in our quest to understand the relationship(s) between psychological processes and brain functioning. Besides, the ever-increasing use of in-vivo imaging techniques has inevitably blurred this distinction, chiefly because they provide the researcher with the opportunity to observe brain activity in healthy individuals as they undertake some sort of cognitive or other psychological challenge, arguably permitting a more direct (i.e., less inferential) link between structure and function.

KEY TERMS

Behaviourism: The school of psychology founded by Thorndike and popularised by Skinner, which places emphasis on the acquisition of behaviour through learning and reinforcement.

Clinical neuropsychology: A branch of clinical psychology that specialises in the assessment of patients with focal brain injury or neurocognitive deficits.

Cognitive neuropsychology: A branch of neuropsychology that studies how brain structure and function relate to specific psychological processes.

In-vivo imaging techniques: A range of imaging techniques that explore structure and/or function in living subjects.

THE ORIGINS OF THE BRAIN HYPOTHESIS

We know from historical records from the Middle East (e.g., the Edwin Smith Surgical Papyrus, found in Luxor, Egypt, in 1862) that the importance of the brain as a “behaviour control centre” (henceforth referred to as the brain hypothesis) was first considered at least 5000 years ago, although the predominant view then, and for many centuries thereafter, was that the heart was the organ of thinking and other mental processes. The ancient Greeks debated the relative merits of heart and brain, and Aristotle, noting that the brain was relatively cool in comparison with the heart, came down in support of the heart as the seat of mental processes, arguing that the brain’s principal role was to cool blood. Hippocrates and Plato, on the other hand, both had some understanding of brain structure, and attributed various aspects of behaviour to it: Hippocrates, for example, warned against probing a wound in the brain in case it might lead to paralysis in the opposite side of the body.

In first-century (ad) Rome, the physician Galen spent some time working as a surgeon to gladiators and became all too well aware of the effects that brain damage could have on behaviour. The “heart hypothesis” was fundamentally undermined by Galen’s descriptions of his clinical observations: he showed that sensory nerves project to the brain rather than the heart, and he also knew that physical distortion of the brain could affect movement whereas similar manipulation of the heart could not.

For reasons that are never entirely clear, the knowledge and understanding of these early writers was lost or forgotten for the next 1500 years or so of European history. Those with any interest in the brain concentrated on attempts to find the location of the soul. Their search focused on easily identifiable brain structures including the pineal gland and the corpus callosum, structures that today are known to be involved in the control of bodily rhythms and communication between the two sides of the brain respectively.

LOCALISATION OF FUNCTION

The renewed interest in rationalism and science that accompanied the Renaissance in Europe in the 15th and 16th centuries prompted scientists of the day to revisit the brain and to try to establish the functions of particular brain structures. Because a lot of brain tissue appears relatively undifferentiated to the naked eye, these researchers also concentrated their efforts on the same easily identified structures as the earlier “soul-searchers”. They explored, for example, the functions of the fluid cavities of the brain (the ventricles), the pineal and pituitary glands, and corpus callosum. However, their ideas about the functions of these structures were usually well wide of the mark: Descartes (1664), for example, mistakenly argued that the pineal gland was the point of convergence of bodily sensory inputs giving rise to a non-physical sense of awareness—thus encapsulating the key idea of the mind–body problem, although it should, perhaps, have been more aptly described as the mind–brain (or even the brain–mind) problem! To reiterate, the pineal gland is today regarded as an entirely soul-less endocrine gland involved in the control of bodily rhythms.

Nevertheless, implicit in this early work was the core idea of localisation of function—that different regions of the brain are involved in specific and separate aspects of (psychological) functioning. This idea later intrigued both Gall, the

KEY TERMS

Paralysis: Loss of movement in a body region (such as a limb).

Sensory nerves: Nerves carrying action potentials from sensory receptors towards the CNS (e.g., the optic nerve).

Descartes: French philosopher famous for his ideas about the separate identities of mind and body.

Mind–body problem: Explaining what relationship, if any, exists between mental processes and bodily states.

Localisation of function: The concept that different parts of the brain carry out different functions and, conversely, that not all parts of the brain do the same thing.

Austrian physician, and his student Spurzheim, whose work represents the starting point of what we might call the modern era of brain–behaviour research. It should be noted at the outset that Gall and Spurzheim, like modern-day neuropsychologists, were more interested in localisation of function within the cerebral cortex (the outer surface of the brain), with its characteristic bumps (gyri) and folds (sulci), than in the subcortical structures mentioned earlier. Gall (1785– 1828) readily accepted that the brain rather than the heart was the control centre for mental function and, with Spurzheim, made several important discoveries about the anatomy of the brain, its connections with the spinal cord, and its ability to control muscles that have stood the test of time. For example, Gall was the first person to distinguish between grey and white matter (neuron cell bodies and their bundled axons respectively) in the brain, and also described the first case of aphasia (impaired language production) associated with frontal damage resulting from a fencing injury.

THE RISE AND FALL OF PHRENOLO...