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Ronald A. Cohen

The Neuropsychology of Attention

Second Edition Ronald A. Cohen, PhD, ABPP, ABCN Professor Departments of , Psychiatry and Aging Director, Center for Cognitive Aging and College of Medicine Gainesville , FL , USA Adjunct Professor Department of Psychiatry and Human Behavior Warren Alpert School of Medicine Brown University Providence , RI , USA

ISBN 978-0-387-72638-0 ISBN 978-0-387-72639-7 (eBook) DOI 10.1007/978-0-387-72639-7 Springer Heidelberg Dordrecht London

Library of Congress Control Number: 2013941376

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Foreword

It has been about 20 years since Dr. Cohen authored the fi rst edition of his book, The Neuropsychology of Attention. In the decade prior to the fi rst edition, major advances had occurred on how the mediates attention and the impact of brain disturbances on attentional functions. This Neuropsychology of Attention did a brilliant job of summarizing and organizing this information. The book was written so clearly and provided so much information that both the novice and expert could understand and learn much from reading it. But this book did even more. When it was written, there was still much that was not understood, and this book excited curiosity and promoted further research. The Malthusian growth model predicts that the world’s population will increase exponentially. I suspect this mathematical growth model also char- acterizes how our knowledge of brain-mediated processes, including atten- tion, has grown. Since the fi rst edition was published two decades ago, the neuropsychology of attention has continued to evolve, and there is now a vast research literature exploring this topic. Thus, the time is ripe for a second edition of The Neuropsychology of Attention. Objects and actions can more easily be de fi ned than mental processes such as attention. Since wrote the Principles of , atten- tion has been defi ned as “…taking possession of the .” We humans are aware that our sensory systems are continuously bombarding our with more information than our brains can simultaneously process in full. Stimuli, however, are not just from external sources. We have the ability to activate stored sensory, perceptual, and conceptual representations. We can see, hear, feel, smell, and taste stimuli that are currently being presented, as well as recall or imagine stimuli that have been previously sensed and even stimuli that have never been sensed. How do we decide what stimuli to fully process and what stimuli not to process and how does our brain implement this triage process? How do we decide to allocate our processing resources on internal vs. external stimuli, and how do we decide as to whether to allocate our resources to a speci fi c sensory modality or a spatial location? How do we decide whether to focus on a specifi c or to take a more global view? How does the brain make decisions regarding how and to what it will selectively allocate atten- tion when engaging in strategic controlled cognitive processes, such as reasoning, , or creative thinking. In regard to attention, our brains have to make four critical attentional deci- sions: When to initiate attention to a stimulus? When to continue to attend?

vii viii Foreword

When to stop attending? And when not to attend? How does our brain mediate these “when” functions? When there is brain dysfunction, one or more of these stages may be impaired and may produce inattention, unawareness, and neglect; impaired vigilance; impaired and extinction; and distractibility. There are many acquired neurological diseases, such as stroke where peo- ple may have dysfunction in one or more of these four processes. However, clinicians and investigators are becoming increasingly aware that these disor- ders of attention are often associated with other diseases, including degenera- tive diseases of the brain, , general medical illnesses, and even with normal aging. Attentional disorders have long been recognized as a critical feature of the attention defi cit hyperactivity disorder; however, atten- tional disorders also can play an important role in other developmental disor- ders. Patients with several psychiatric disorders, including autism, depression, bipolar, anxiety, and schizophrenia, also have impairments of attention. As mentioned in the foreword for the fi rst edition, there are many means by which attention and disorders of attention have been studied. Cognitive and experimental who initially studied normal subjects using behav- ioral paradigms such as priming, cueing, reaction times, dichotic listening, and tachistoscopic presentations are now using functional imaging, especially func- tional magnetic resonance imaging (fMRI), and there has been an explosion of studies using fMRI. For example, I opened PubMed and typed in “attention and fMRI.” There were more than 7,000 papers listed. Electrophysiological studies of healthy people and patients with neurological and psychiatric disorders con- tinue to provide important insights into the neural mechanisms of attention. Findings from humans have been augmented by a large body of research in laboratory animals employing single-cell recordings and other neurophysiolog- ical methods. Neuropsychologists have developed many new tests for assess- ing disorders of attention, and they along with neurologists, psychiatrists and other neuroscientists continue to study the pathophysiology of diseases that attention. This second edition of the Neuropsychology of Attention takes the reader on a wonderful journey, from the late eighteenth century to the twenty-fi rst cen- tury. While the title of this book is Neuropsychology and does discuss testing, this book covers almost all methods of studying attention, including the con- tributions made by the cognitive and experimental psychologists, the physio- logical psychologists, the neuropsychologists, as well as the behavioral neurologists and psychiatrists. When viewing a Navon fi gure, the normal per- son will allocate both local and global attention. Thus, they will be able to see the local stimuli as well as how these local stimuli relate to each other, the global picture. In parallel, the means in which this book has been written not only allows the reader to learn about the important specifi c clinical and research reports of specialized investigators but also allows the reader to see the “big picture” about what we have learned and what we still need to learn.

Kenneth M. Heilman, MD Professor of Neurology and Department of Neurology University of Florida College of Medicine Gainesville, Fl, USA Preface

Attention played a vital role in the historical development of the fi eld of psychology. Early psychologists pondered the nature of attention and attempted to characterize its phenomenology and constituent processes. Attention was considered to be a fundamental and inescapable aspect of human experience by , William James, and other founders of modern psychology. Yet, for much of the early twentieth century, psychologists avoided the construct of attention, and relatively little experimental study of attention took place before the 1960s. Because attention has an intangible quality and cannot be speci fi ed as a unitary process, many behavioral scientists considered the construct of attention to be metaphysical or at the very least theoretically incoherent. Some of their concerns regarding the nature of atten- tional phenomena were clearly justi fi ed. Yet, it was also apparent to most psychologists that explanations of behavior and that failed to account for attention were phenomenologically and conceptually incomplete. In the 1970s, there was a major shift in zeitgeist, as cognition increasingly became an accepted topic of scienti fi c inquiry. This shift corresponded with the onset of the information age and rapid developments in computer science. Cognitive scientists increasingly incorporated concepts arising out of informa- tion-processing theory to explain cognitive phenomena, such as how people selectively attend to particular information in their environment. Humans clearly cannot handle an infi nite amount of simultaneous information. Cognitive processes must exist which serve to reduce the information derived from sensory input to manageable levels, to select particular stimuli and responses from the vast universe of alternatives, while eliminating other less relevant information from immediate consideration, and to direct optimal focus on information that is most salient. While the specifi c mechanisms and functional brain systems underlying these processes were not well understood, it was apparent to early cognitive scientists that accounting for and explaining the occurrence of phenomena normally labeled as attention and was essential to a complete understanding of cognition. The necessity of studying attentional phenomena is particularly evident within neuropsychology. Patients with brain disorders frequently do not per- form at optimal levels, even when task variables are held constant. They may fail to detect an object in the environment, even though it can be demon- strated that they have adequate perceptual capability. Inconsistent perfor- mance is often attributed to attentional factors. Yet, even today, attention is not comprehensively assessed as part of most routine neuropsychological

ix x Preface evaluations, even though disorders of attention are now recognized as being very common. Historically, few systematic clinical approaches existed for assessing attention. Over the past two decades, considerable effort has been directed at developing neuropsychological tests of attention. Furthermore, consideration of underlying attentional mechanisms and impairments arising from disruption of these mechanisms is now much more central to neuropsy- chological inquiry. While many of the concepts, models, theories, and meth- ods for studying attention were beginning to emerge during the late 1980s prior to the fi rst edition of this book, there was a clear lack of coherence in the neuropsychology of attention. This is no longer the case. While debate continues over whether certain processes are best considered as aspects of attention, memory, or other cognitive processes, there is now much greater agreement over what constitutes attention, how it relates to other cognitive processes, and also regarding the underlying brain systems and physiological mechanisms responsible for attending. The necessity of studying attentional phenomena is particularly evident within neuropsychology. Patients with brain disorders frequently do not perform at optimal levels, even when task variables are held constant. They may fail to detect an object in the environ- ment, even though it can be demonstrated that they have adequate percep- tual capability. Inconsistent performance is often attributed to attentional factors. Yet, even today, attention is not comprehensively assessed as part of most routine neuropsychological evaluations, even though disorders of attention are now recognized as being very common. Historically, few systematic clinical approaches existed for assessing attention. Over the past two decades, considerable effort has been directed at developing neuropsy- chological tests of attention. Furthermore, consideration of underlying attentional mechanisms and impairments arising from disruption of these mechanisms is now much more central to neuropsychological inquiry. While many of the concepts, models, theories, and methods for studying attention were beginning to emerge during the late 1980s prior to the fi rst edition of this book, there was a clear lack of coherence in the neuropsy- chology of attention. This is no longer the case. While debate continues over whether certain processes are best considered as aspects of attention, memory, or other cognitive processes, there is now much greater agreement over what constitutes attention, how it relates to other cognitive processes, and also regarding the underlying brain systems and physiological mecha- nisms responsible for attending. These considerations motivated the fi rst edition of this book in the late 1980s. The fi rst edition of the Neuropsychology of Attention was a compre- hensive overview of the fi eld. It included three major parts. The fi rst part presented information about the history of attention within psychology, the cognitive science of attention, behavioral approaches, and psychophysiologi- cal approaches. Part II provided a review of the neuropsychological manifes- tations of disorders affecting attention, with chapters on neurological and psychiatric disorders that affect attention, neuropsychological assessment of attention, and neuropsychological models of attention. Part III was directed at a review of theoretical issues in the analysis of attention, including factors that constrain attentional performance (e.g., memory, spatial and temporal Preface xi

dynamics, processing speed). An examination of computation models of attention was also included. It has been 20 years since the original publication of the Neuropsychology of Attention . The emphasis placed on the study and assessment of attention has increased dramatically since that time. At the time of its publication, attention was a construct that had long been of theoretical interest in the fi eld of psychology and was receiving increased research by cognitive scientists. Yet, attention was typically viewed as a nuisance variable, a factor that needed to be accounted for when assessing brain function but of limited importance in its own right. Neuropsychological interest in attention has steadily increased. Several factors contribute to this. (1) Attention is comprised of processes that govern the moment-by-moment interface of internal cognitive experience with the outside world. (2) It has become apparent that attention is one of the most vulnerable cognitive functions. Attention is affected by a wide range of medical and psychiatric conditions. (3) We are now able to bet- ter operationalize and assess attention in a systematic way. (4) Problems with attention are increasingly being reported by people in the , in part due to the increased complexity and pace of modern living. Attention Defi cit Disorder (ADD) has become one of the most widely diagnosed condi- tions of childhood. (5) Rapid advances in functional brain imaging have enabled the measurement of brain activity associated with cognitive processes. Brain activation occurs in response to the momentary processing demands that exist during the task, which typically involve strong attentional involvement. The brain systems that most commonly activate during functional imaging (e.g., cingulate cortex, ) are areas known to play essential roles in attention. In light of these facts, there has been an explosion of inter- est in the neuropsychology of attention. Over the past two decades, there has been a virtual explosion of clinical, cognitive, and neuroscience research directed at better understanding atten- tion and its underlying processes. The number of published manuscripts addressing the functional neuroanatomic and the neural bases of attention has increased geometrically, and attention is now a major focus of many studies utilizing functional brain imaging methods to study cognition. Review of published articles accessible through PubMed suggests that since 1995, over 20,000 studies have been published examining the neural bases of attention and clinical disorders of attention associated with various neurological and psychiatric disturbances. A large number of these studies include neuropsy- chological investigations of clinical disturbances of attention. Accordingly, the time is ripe for a reconsideration of the neuropsychology of attention at this point in the early twenty- fi rst century. In light of the many advances in the neuroscience of attention, several top- ics warranted greater consideration in this second edition. 1. Functional was in its infancy when the fi rst edition of this book was written. Knowledge of the neural mechanisms underlying attention came primarily from psychophysiological studies employing methods based on EEG, electrophysiological and ablation studies of laboratory animals, and of course the analysis of neuropsychological abnormalities secondary to brain lesions in humans. While these continue to be important methods for the xii Preface

study and clinical assessment of attention, functional neuroimaging has had a profound impact on the neuroscience of attention. Many functional neu- roimaging fi ndings that emerged over the past two decades are reviewed, and an entire chapter has been devoted to the neuroimaging of attention. 2. The construct of working memory and its relationship to attention was not well developed, so this received limited coverage. 3. The literature on attention disturbances associated with speci fi c neurologi- cal disorders was limited at the time; therefore, this information was sum- marized with less detail than would be optimal. At this point, there is considerable knowledge regarding attention disturbances associated with speci fi c neurological and psychiatric conditions that should be integrated. 4. The clinical assessment part is dated. There are now many more tests of attention that should be reviewed. 5. Attention was largely not reviewed from a developmental perspective in the fi rst edition. There is a need for integration of work coming from the study of child psychology, and this fi ts with and informs about the neurop- sychology of attention more broadly. 6. Treatment approaches (pharmacological and behavioral) received only limited coverage in the fi rst edition. Accordingly, there was a need for a new edition of this book to present an updated and integrated review of what is known about attention, the disorders that affect it, and approaches to its clinical assessment and treatment. Such a book will provide perspectives for experimental neuropsychological study of attention and also provide clinicians with insights on how to approach this neuropsychological domain. The second edition of the Neuropsychology of Attention was written with several goals in mind: (1) to provide an update on the large body of experi- mental and clinical fi ndings regarding the neuropsychological bases of atten- tion, (2) to examine the degree to which previous theories and models fi t with current evidence regarding the underlying processes and the functional brain systems known to govern attention, (3) to provide a more focused and thor- ough review of how attention has been approached in the context of the dra- matic developments that have occurred in functional and structural brain imaging, (4) to provide an expanded review of neuropsychological research on the disorders of attention associated with specifi c neurological and psychi- atric conditions, and (5) to update readers on current methods for assessing attentional disturbances. The overall goal of this second edition of the Neuropsychology of Attention is to provide a synthesis of theories, concepts, and experimental fi ndings regarding the processes and brain mechanisms responsible for normal and disordered attention in humans. As in the fi rst edition, Part I introduces and reviews basic concepts that provide the conceptual foundation for neuropsychological consideration of attention. Theoretical and empirical information that provides the founda- tions for the neuropsychology of attention has come from many different disciplines within the fi elds of psychology, cognitive science, neuroscience, and medicine. Historically, there was often relatively little exchange between these different scienti fi c disciplines, which probably accounted for the lack of coherence in the research being conducted on attention and even the Preface xiii

and concepts used to explain attentional phenomena. Accordingly, it was nec- essary to establish the features common among the different approaches to the study of attention, as a starting point for subsequent analysis. Without consistency across constructs used to de fi ne and characterize attention, scienti fi c inquiry into the neuropsychological bases of attention seemed fraught with problems. Over the past two decades, greater coherence has been achieved both with respect to the language used to describe and study atten- tion and also underlying processes and mechanisms. Conceptual frameworks have been developed, tested, and employed. Consequently, neuropsychologi- cal study of attention is now much more feasible than in the past. Yet, for neuropsychologists and students who come to the study of attention at this point in time and who have not witnessed the evolution of the constructs and research that occurred over the last half of the twentieth century, it is also easy to overlook the origins of current thinking regarding neuropsychology of attention. Consideration of past cognition, behavior, and neurophysiological research on attention provides a useful historical perspective and important conceptual foundations necessary for systematic neuropsychological study of attention and the brain disorders that affect attention. Accordingly, we again begin Part I of the second edition of this book with consideration of the roots of current theories of attention in philosophy, cogni- tive psychology, , and psychophysiology and then proceed to con- sider the neuropsychology of attention as it now exists in the twenty- fi rst century. Several broad domains of theoretical and experimental knowledge of relevance to the study of attention are addressed: (1) information-processing models, (2) other cognitive approaches, (3) behavioral theories of attention, and (4) psychophysiological and neurophysiological evidence regarding the nature and mechanisms of attention. There has been little previous integration of attentional concepts developed from these different domains, though this is not altogether surprising if one considers the different scienti fi c and philo- sophical perspectives that each represents. An attempt is made to present the strengths and weaknesses of each of these approaches and to develop a more unifi ed conceptual framework regarding the cognitive, behavioral, and neural mechanisms of attention. Attention directed at response selection and control (executive–attention) is reviewed, as well as both sustained and focused atten- tions. At the end of Part I, a theoretical framework of attention is presented that is applied to subsequent discussions of the neuropsychology of attention. In Part II, neuropsychological disturbances of attention are reviewed with consideration of the functional neuroanatomic systems that are affected by different disorders. This part has been expanded since the fi rst edition, as attention has now been studied extensively with respect to a number of neuro- logical and psychiatric disorders. Attention disturbances observed with these disorders are reviewed in greater detail. Consideration of brain disorders on attention provides an important means of understanding the role played by particular brain systems for attention. Disturbances of sensory selective atten- tion, including those associated with hemineglect syndrome, are considered in Chapter 12. Experimental animal and human studies that have delineated the neural systems underlying selective attention are reviewed. Disorders of response intention and more broadly executive–attention are reviewed next. xiv Preface

This is followed by consideration of the role of frontal cortical systems (Chapter 13 ) and subcortical and limbic in fl uences (Chapter 14 ). Speci fi c neu- rological diseases that affect attention are reviewed in Chapter 15 , including Alzheimer’s disease, subcortical neurodegenerative diseases (e.g., multiple sclerosis, Parkinson’s disease, Huntington’s disease), cerebrovascular disease, traumatic brain injury, seizure disorders, and HIV. Systemic medical illnesses that affect attention are then reviewed in Chapter 16, including the impact of metabolic disturbances and attention dysfunction in the context of delirium. Attentional infl uences on behavioral risk factors for illness are also considered. Next, psychiatric conditions that affect attention are considered (Chapter 17 ), followed by Attention Defi cit Disorder (Chapter 18). A number of books are now devoted to ADD. Chapter 18 contains an overview of this literature, with a speci fi c emphasis placed on the nature of the attentional disturbances that occurs and presumed neural underpinnings. Chapter 19 reviews neurop- sychological assessment of attention, with discussion of both neuropsycho- logical and more traditional psychological methods of evaluating attentional dysfunction. Experimental methods developed from information-processing approaches are also described. This chapter has been expanded to discuss cer- tain tests that were developed since the fi rst edition that have had an impact on the fi eld. Inventories used in the behavioral assessment of ADD are also dis- cussed. Neuropsychological models and frameworks developed to account for attention are reviewed in the fi nal chapter of Part II. Attention occurs as a function of multiple interacting neural systems in response to exogenous stimuli from the environment and endogenous organ- ismic in fl uences. Accordingly, it is important to consider neural, behavioral, and physical constraints on attention, as well as the relationship between attention and related experiences, such as consciousness and awareness. Part III begins with a discussion of the relationship between consciousness, self- awareness, and attention. This is followed by a consideration of neural con- straints on attention (Chapter 22 ) and then of speci fi c factors that in fl uence attention, including processing speed and cognitive resources (Chapter 23 ), memory (Chapter 24), and spatial and temporal dynamics (Chapter 25 ). Chapter 26 addresses neuroimaging methods for the study of attention. Computational neuroscientifi c approaches are considered in Chapter 27 , including neural network and connectionist models of attention. Computational models provide formal operational systems for examining specifi c theories of attention and testing whether conceptualized attentional processes are feasi- ble and fi t with empirical evidence from cognitive and neuropsychological studies of human performance. The fi nal chapter provides a synthesis of cog- nitive, behavioral, and neural mechanisms underlying the attention. Neuropsychological models of attention are reexamined in light of this syn- thesis. The second edition of the Neuropsychology of Attention provides a foundation for understanding the processes and disorders of attention and their underlying neural mechanisms.

Gainesville, FL, USA Ronald A. Cohen Acknowledgements

Several people were instrumental in bringing this book to fruition. I am also deeply indebted to my wife, Kim Sandler, for her emotional support and the many hours she spent editing this book. Brian O’Donnell and Yvonne Sparling collaborated with me on this book’s fi rst edition, coauthoring several chapters. They both made important contributions for which I am very grateful. Many hours were spent engaged in stimulating discussion on the nature of attention, consciousness, and neurophilosophy with my son, Brent Cohen. His background in philosophy and formal logic was very helpful with respect to philosophical perspectives and computational modeling of attention and also for the chapter on consciousness. Similarly, I benefi ted from many hours of discussion with my lifelong friend Edward Hansch. My father, Gary Cohen, produced most of the original artwork for this book. Thanks also to my daughter Lauren Cohen who produced a rendering of the thalamus for this edition of the book. Both my par- ents, Gary and Ann Cohen passed away several years ago. I am forever grateful for the love and support that they gave to me throughout my life. The writing of this book was facilitated by my collaboration with many colleagues, teachers, students, and friends. William Waters served as my pri- mary mentor in graduate school and introduced me to the concepts of sensiti- zation and habituation of the orienting response and its relationship to attention. Chizuko Izawa, Seth Kunen, and James May were also among the professors in cognitive sciences who stimulated my interest in the topic of attention. My experience as an intern and fellow at UCLA and then at the University of Florida was invaluable, enabling me to develop a strong foundation in . I spent many hours with Paul Satz during my time at UCLA. He had joined the faculty several months after the start of my internship. I had the pleasure of getting to know him as he initiated the devel- opment of a new clinical neuropsychological program. Paul contacted and introduced me to , which led to my post-doctoral fellowship at the University of Florida. It was with great sadness that I learned that Paul Satz had passed away last year. He made a signifi cant contribution to the fi eld of neuropsychology and will be missed. While a fellow at the University of Florida, I had the opportunity to work with many leaders in the fi eld of neuropsychology, including Eileen Fennell, Russell Bauer, Dawn Bowers, Leslie Gonzalez-Rothi, and Mieke Verfaillie in neuropsychology and Kenneth Heilman, Edward Valenstein, Robert Watson, and Branch Coslett in . Sadly, Dr. Valenstein also passed away this year.

xv xvi Acknowledgements

I maintained close relations with this group over the years. I am particularly grateful for the mentoring and guidance that Dr. Heilman gave me over the years and for recommending that the Institute on Aging recruit me to direct the new Center for Cognitive Aging and Memory at the University of Florida. The completion of this book took place during my transition from Brown University to this new role. My fi rst academic position was as an assistant professor at the University of Massachusetts Medical School where I worked with Brian O’Donnell, Guila Glosser, Donald Stein, Joan Swearer, Russell Barkley, Robert Kane, Allen Rosenbaum, Daniel Pollen, and David Drachman. Russell Barkley and I spent many hours discussing the neural substrates of ADD, including stud- ies that we were conducting on attention and timing. Marc Fisher has been a close friend and colleague over the past 30 years. He introduced me to the neurology of stroke, and together we initiated early studies of vascular demen- tia, including my serving on the workgroup that formulated the NINDS- AIREN criteria for vascular . Similarly, Richard Kaplan has been a close friend and colleague over the course of my career. We published many papers together, including investigations of the factors infl uencing inattention in neglect syndrome and my studies of the effects of cingulotomy. Prior to coming to the University of Florida this year, I served as a Professor at Brown University for 20 years. I am appreciative of my colleagues there, Paul Malloy, Robert Stern, Brian Ott, Edward Stopa, Suzanne de la Monte, David Abrams, Peter Monti, Michael Carey, Bess Marcus, Rena Wing, Karen Tashima, and Charles Carpenter, to name a few. I was fortunate to have many outstanding students, interns, and fellows for whom I served as a mentor at Brown University, including David Moser, Katarina Lukatela, Melissa Jenkins, Robert Paul, Patricia Boyle, Jeffery Browndyke, Tricia Zawacki-King, Lawrence Sweet, John Gunstad, David Tate, Angela Jefferson, Adam Brickman, Molly Zimmerman, Karin Hoth, Andreana Haley, Jason Hassenstab, and Assawin Gongvatana. I am proud of the fact that all of these individuals have gone on to academic positions throughout the country. I am particularly grateful to Robert Paul who went on to become a faculty member in my group and a close collaborator during a highly productive decade of research together. Similarly, I am grateful to Lawrence Sweet who we fi rst recruited as an intern. He went on to a fellowship and eventually rose to the rank of associate professor at Brown University. He was essential in working with me to develop functional neuroimaging at Brown. I am especially grateful to Assawin Gongvatana. He was my last fellow at Brown and went on to become an assistant professor in my group. We collaborated on many of my neuroimag- ing initiatives and studies of neuro-HIV over the past four years. Besides being a close collaborator and friend, Win was instrumental in generating many of the images included in the book from data collected from our research studies. I am also very thankful to Janice Stern, my editor at Springer, who encour- aged me to write a second edition and who provided essential insights and support. Joseph Quatela worked with me in the production and copy editing of this book. Also, special thanks to Elliott Werner and Tony Puente for their help in making the fi rst edition of this book a reality. Much gratitude to Talia Seider, currently a graduate student in clinical neuropsychology at the University of Florida and a member of my laboratory, who reviewed the copy edited version of the book and helped with the fi nal revisions for many of the chapters. Contents

Part I Foundations of Attention

1 Introduction ...... 3 Introduction ...... 3 Varieties and Manifestations of Attention ...... 5 Focused Attention ...... 5 Selective Attention ...... 5 Divided Attention ...... 5 Sustained Attention ...... 6 Effortful Attention ...... 6 Intention and Directed Attention ...... 6 Constraints on Attention ...... 7 Neural Constraints ...... 7 Processing Speed and Resources ...... 7 Memory and Attention ...... 7 Spatial–Temporal Constraints ...... 8 Consciousness, Awareness, and Self-Directed Attention ...... 8 A Unified Neuropsychological Model of Attention ...... 8 Sensory Selection ...... 8 Executive–Attention: Response Selection and Control ...... 9 Focused Attention/Capacity ...... 9 Sustained Attention ...... 9 Neuropsychological Foundations ...... 10 2 Historical and Philosophical Antecedents ...... 11 References ...... 16 3 of Attention: Foundations ...... 19 Communication, Control, and Information Processing ...... 19 The Communication System ...... 20 Information ...... 20 Channels, Channel Capacity, and Coding ...... 21 Noise and Redundancy ...... 21 ...... 22 Developments and Limitations ...... 22

xvii xviii Contents

Psychology and Information Processing ...... 23 Capacity, Channels, and Filters in the Human Nervous System .... 23 Models of Selective Attention ...... 27 Selective Attention and Channels ...... 27 Automatic and Controlled Processing ...... 38 What Processes Are Automatic? ...... 38 Automatization and Capacity ...... 39 A Structural Model of Automatic and Controlled Processes ...... 42 Capacity, Resource, and Skill ...... 44 Performance Operating Characteristics ...... 46 Critiques of Resource Models ...... 48 Conclusions ...... 50 References ...... 51 4 Cognitive Science of Attention: Current Concepts and Approaches ...... 55 Covert and Overt Orienting of Attention ...... 55 Local and Global Processes ...... 55 Flanker Compatibility ...... 56 Perceptual Load ...... 56 Inhibition of Return ...... 57 Concurrent Task Performance: Divided Attention ...... 57 Stimulus–Response Compatibility ...... 58 Attentional Blink ...... 58 Symbolic Control Processes ...... 59 Attention Across Sensory Modalities ...... 59 Attention-Executive Control System ...... 60 Cognitive Science of Attention: Into the Future ...... 61 References ...... 62 5 Intention, Response Selection, and Executive-Attention ...... 69 Late Selection Models ...... 70 Capacity Constraints and Response Demands ...... 71 Motoric Influences on Attention ...... 74 Motor Activation During Covert Processing ...... 75 Looking and Attending ...... 75 Experimental Evidence of Premotor Attentional Control ...... 79 Visual–Motor Integration During Attending ...... 80 Executive Control of Attention ...... 81 Disorders of Intention ...... 82 Summary ...... 82 References ...... 83 6 Focused and Sustained Attention ...... 89 Attentional Focus ...... 90 Focus During Selective Attention ...... 90 Focused Attention for Response Selection and Control ...... 91 Focus and Divided Attention ...... 92 Contents xix

Focused Attention and Working Memory ...... 93 Processing Speed, Attentional Capacity, and Focus ...... 94 Sustained Attention: Effort, Vigilance, and Fatigue ...... 94 Vigilance and Sustained Attention ...... 95 Psychophysical Determinants of Vigilance and Sustained Attention ...... 97 Effort: An Attentional Constraint ...... 98 Neurobehavioral Characteristics of Fatigue ...... 101 and Circadian Effects on Attention and Fatigue ...... 105 Conclusions ...... 105 References ...... 106 7 Behavioral Perspectives ...... 113 Early Theory ...... 114 Classical Conditioning ...... 115 Expectancy and Anticipation ...... 116 Generalization ...... 117 The Orienting Response ...... 117 Habituation of the OR ...... 118 The OR as an Attentional Index ...... 118 Operant Conditioning ...... 119 Discrimination Learning ...... 120 Observing Responses ...... 121 Blocking ...... 122 Extinction: A Control Mechanism of Attention ...... 122 Neobehavioral Contributions ...... 123 Behavioral Inhibition ...... 123 Conditioned Inhibition ...... 124 Measurement of Behavioral Inhibition ...... 124 Disinhibition ...... 125 Cue Dominance ...... 126 Drive and ...... 128 Summary ...... 129 References ...... 130 8 The Orienting Response: Index of Attention ...... 135 Stimulus Characteristics and the OR ...... 135 Novelty and the OR ...... 136 Information Content ...... 136 Stimulus Uncertainty and Change ...... 137 Stimulus Intensity and Duration ...... 138 Interstimulus Interval ...... 138 Characteristics of the OR ...... 138 Habituation of the OR ...... 140 Conditioning and the OR ...... 141 Intentionality and the OR ...... 142 Neural Mechanisms of the OR and Habituation ...... 142 Dual-Process Theory ...... 144 Alternative Theories of Habituation ...... 145 xx Contents

Evaluation of Habituation Theories ...... 147 Neuropsychological Evidence ...... 149 Summary ...... 152 References ...... 152 9 of Attention ...... 159 , , and Physiological Response ...... 160 Arousal: An Attentional Catalyst ...... 161 Arousal as a State Function ...... 161 Tonic and Phasic Physiological States ...... 162 Tonic Arousal and Performance ...... 162 High and Low Arousal ...... 163 Problems with Generalized Arousal ...... 164 Alternatives to Generalized Arousal ...... 165 Physiological Correlates of Attending ...... 167 Arousal and the OR ...... 167 Autonomic Manifestations of Attention ...... 168 Pupillary Responses and Memory Load ...... 171 Motor Activation During Attention ...... 172 Do Bodily Responses Facilitate Attention? ...... 173 Induced Arousal ...... 174 Induced Physiological State ...... 174 Electroencephalographic Correlates of Attention ...... 175 Sensory Evoked Potentials ...... 176 Attentional Components ...... 177 The Negative Difference Response and Auditory Selective Attention ...... 177 ERPs and Visual Selective Attention ...... 178 The P3 and Attention ...... 180 Probability and Task Relevance ...... 181 Stimulus Evaluation ...... 182 Guessing and Betting ...... 182 Mental Load and Cognitive Resources ...... 182 Late Cognitive EP Components ...... 183 Source Analysis, Topographic Mapping and Meg ...... 183 EEG Coherence, Theta, and Phase Synchrony ...... 184 EEG Findings with Brain Dysfunction ...... 185 Aging ...... 186 Neurodegenerative Diseases ...... 187 Attention Deficit Disorder ...... 188 Psychiatric Disorders ...... 189 Evoked Potentials and Neurocognitive Performance ...... 190 Significance of the N2–P3 Complex in Attention ...... 190 Deep Brain Measurement and Stimulation ...... 191 Summary ...... 192 References ...... 194 Contents xxi

10 Neural Mechanisms of Attention ...... 211 Attention as an Aspect of Conditioning ...... 212 Bioelectrical Indices of Conditioning and Attention ...... 213 Long- and Short-Term Neural Modifications ...... 214 Conditioning in Simple Neural Systems ...... 215 Cellular Modifications During Conditioning ...... 218 Plasticity in the Mammalian Nervous System ...... 219 Sensory Systems ...... 220 Bioelectrical Activity in Humans ...... 221 Sites of Neuronal Plasticity in Humans ...... 222 Inhibitory and Facilitatory Attentional Mechanisms ...... 225 Neural Inhibitory Mechanisms ...... 227 Limbic Influences on ...... 228 Neural Mechanisms of Selective Attention ...... 233 Mechanisms of Visual Selective Attention ...... 234 Attentional Selection and Engagement ...... 237 Shifting Attention ...... 238 Initiation of Saccadic Eye Movement ...... 239 Response Intention and Selection ...... 240 Arousal Effects on Attentional Response...... 242 Mechanisms of Auditory Selective Attention ...... 242 Attention in Other Sensory Modalities ...... 244 Summary ...... 245 References ...... 246 11 Models and Mechanisms of Attention ...... 265 Sensory Selective Attention ...... 266 Cognitive Psychology ...... 267 Behavioral Psychology ...... 268 Psychophysiology ...... 268 Neuroscience ...... 269 Executive–Attention ...... 269 Cognitive Psychology ...... 270 Behavioral Psychology ...... 271 Psychophysiology ...... 272 Neuroscience ...... 272 Focused Attention-Capacity ...... 273 Cognitive Psychology ...... 275 Behavioral Psychology ...... 276 Psychophysiology ...... 276 Neuroscience ...... 277 Sustained Attention ...... 278 Cognitive Psychology ...... 278 Behavioral Psychology ...... 278 Psychophysiology and Neuroscience ...... 279 Conclusion ...... 279 References ...... 280 xxii Contents

Part II Neuropsychology of Attention

12 Disorders of Sensory Selective Attention ...... 283 Hemineglect and Inattention Syndrome ...... 283 Incidence ...... 284 Clinical Presentation ...... 285 Neuropsychological Findings ...... 287 Neglect as an Attentional Disturbance ...... 292 Affective and Memory Influences on Neglect ...... 294 Mechanisms Underlying Neglect Syndrome ...... 295 Which Hypothesis Is Correct? ...... 298 Neglect, the Orienting Response and Arousal ...... 298 Functional of Neglect ...... 299 Contributions ...... 300 Parietal–Temporal Mechanisms of Attention ...... 301 Parietal Contributions to Selective Attention ...... 302 Parietal Response to Shifts of Attention ...... 304 Attentional Search ...... 304 Attentional Influence of Other Parietal Regions ...... 305 Temporal Lobe Contributions to Attention ...... 307 Attention Across the Cerebral Hemispheres ...... 314 Locus of Functional Asymmetries ...... 315 Summary ...... 319 References ...... 320 13 Attention and the Frontal Cortex ...... 335 Functional Neuroanatomic Considerations ...... 336 Afferent and Efferent Connections ...... 338 Clinical Manifestations ...... 339 Ablation Studies ...... 341 Attention, Movement, and Action ...... 342 Eye Movements and Attention ...... 343 Frontal Control Mechanisms of Attention ...... 345 Attention and Executive Control ...... 347 Arousal and Activation ...... 350 Temporal Disturbances Associated with Frontal Lobe Dysfunction ...... 353 The Cingulate Cortex ...... 354 Cingulate Influences on Cognition ...... 354 Cingulate Effects on Habituation ...... 357 Attention–Emotional Integration of the Anterior Cingulate ...... 360 Multiple Anterior Cingulate Subsystems ...... 361 Anterior Cingulate Influences Role in Conflict Monitoring ...... 362 Posterior Cingulate Cortex Revisited ...... 363 References ...... 363 Contents xxiii

14 Subcortical and Limbic Attentional Influences ...... 381 Functional Neuroanatomic Considerations ...... 381 The Reticular System ...... 383 Thalamic Influences ...... 386 Basal Ganglia ...... 389 The Cerebellum ...... 392 Cerebellar Attention Dysfunction ...... 395 Hypothalamic Influences ...... 396 Attentional Effects ...... 400 Affective and Motivation Influences of the and Septal Nuclei ...... 402 Hippocampal Influences on Attention ...... 406 References ...... 409 15 Attention Disturbances Associated with Neurological Disease ...... 429 Localized and Nonlocalized Brain Dysfunction ...... 429 Alzheimer’s Disease ...... 430 Subcortical Diseases ...... 434 Parkinson’s Disease ...... 435 Huntington’s Disease ...... 440 Multiple Sclerosis ...... 444 Traumatic Brain Injury ...... 452 Clinical Presentation and Sequelae ...... 452 Attentional Effects of TBI ...... 454 Other Neurological Conditions ...... 459 Seizure Disorder ...... 459 Brain Neoplasm ...... 463 References ...... 464 16 Medical Disorders and Behavioral Risk Factors ...... 491 Cardiovascular Disease ...... 491 HIV-Associated Neurocognitive Dysfunction ...... 495 Clinical and Disease Factors Affecting Brain Function ...... 497 Metabolic Disturbances ...... 502 Chemotherapy and Iatrogenic Treatment Effects...... 504 References ...... 506 17 Psychiatric Disturbances of Attention ...... 525 Affective Disorders ...... 525 Neurobiological Mechanisms ...... 527 Early Neuropsychological Findings ...... 530 Attention Disturbances of Major Affective Disorders ...... 533 Schizophrenia ...... 536 Etiology ...... 537 Neuropathology and Pathophysiology ...... 538 Disturbed Attention as a Hallmark of Schizophrenia ...... 538 Anxiety and Stress ...... 548 Attentional Influences in Behavioral Medicine ...... 552 References ...... 553 xxiv Contents

18 Developmental Disorders of Attention ...... 583 Normal Development of Attention Development ...... 583 Attention Deficit and Hyperactivity Disorders ...... 586 Neural Bases of ADHD ...... 597 Structural Brain Abnormalities ...... 602 Functional Neuroimaging ...... 603 Summary and Integration ...... 604 References ...... 607 19 Clinical Considerations: Assessment and Treatment...... 637 Clinical Assessment and Behavioral Observation ...... 638 Psychometric Approaches ...... 642 Neurocognitive Tests of Attention ...... 646 Selective Attention ...... 646 Sustained Attention ...... 650 Attentional Capacity and Focus ...... 651 Experimental Methods ...... 661 Psychophysical and Signal-Detection Methods ...... 662 Chronometric Methods ...... 665 Physiological and Neuroimaging Methods ...... 666 Experimental Attention Paradigms ...... 666 Vigilance Tasks ...... 670 Scanning and Search Tasks ...... 671 Divided Attention ...... 671 Steps in Decision Making for the Assessment of Attention ...... 673 Summary ...... 674 References ...... 675 20 Neuropsychological Models of Attention ...... 687 Models Based on Hemi-Neglect Syndrome ...... 687 Heilman, Watson, and Valenstein ...... 687 Marcel Mesulam ...... 691 Michael Posner ...... 693 Attention and Arousal ...... 694 Pribram and McGuinness ...... 695 Models of Executive: Attention ...... 696 ...... 696 Timothy Shallice ...... 698 ...... 698 Neuropsychological Taxonomy of Attention: Allan Mirsky ...... 699 Integrated Neuropsychological Framework of Attention ...... 700 Sensory Selection ...... 700 Executive–Attention ...... 704 Attentional Focus and Capacity ...... 706 Sustained Attention ...... 710 Framework Validation and Clinical Manifestations...... 711 References ...... 716 Contents xxv

Part III Toward an Integrated Attentional Framework

21 Consciousness and Self-Directed Attention ...... 721 Self-Awareness ...... 723 Models of Consciousness and Awareness ...... 724 Neuropsychology of Attention and Consciousness ...... 726 Disturbances of Consciousness and Self-Awareness ...... 727 Summary ...... 729 References ...... 731 22 Neural Constraints on Attention ...... 735 Brain Structure and Cytoarchitecture ...... 736 Redundancy and Stereotopy ...... 738 Dynamics of Neural Activation, Spread, and Recruitment ...... 739 Rate of Neural Transmission ...... 740 Cognitive and Behavioral Timing ...... 742 Memory Constraints ...... 743 Neural Plasticity ...... 744 Modality-Specific Constraints ...... 744 Feedback and Feedforward Arrangements ...... 745 Summary ...... 747 References ...... 748 23 Processing Speed and Attentional Resources ...... 751 Attentional Capacity and ...... 751 Capacity, Resources, and Cognitive Reserve ...... 752 Processing Speed and Cognitive Capacity ...... 753 Processing Speed Constraints of Attention ...... 755 Processing Speed and Brain Dysfunction ...... 756 Summary ...... 757 References ...... 758 24 Mutual Constraint of Memory and Attention ...... 763 Systemic Memory Constraints on Attention ...... 763 On the Nature of STM ...... 764 Very-Short-Term Memory ...... 765 Specific Memory Constraints on Attention ...... 765 Decay Rates ...... 765 Limited-Capacity Short-Term Storage ...... 766 Short-Term Storage and Attention ...... 766 Working Memory and Focused Attention ...... 767 Long-Term Storage: Capacity and Durability ...... 768 Semantic and Contextual Constraints ...... 769 Stimulus Salience and Attention ...... 770 Salience, Semantics, and Attention ...... 770 Semantic Memory Organization ...... 771 Determinants of Attention to Semantic Associative Memory ..... 772 Summary ...... 774 References ...... 775 xxvi Contents

25 Spatial and Temporal Dynamics of Attention ...... 779 Spatial Constraints on Attention ...... 780 Phenomenological Considerations ...... 780 Visuomotor Contributions ...... 780 Spatial Distribution of Selective Attention ...... 781 Neural Determinants of Spatial Behavior ...... 786 Spatial Functions of the Parietal Cortex ...... 786 Eye-Movement Control ...... 788 Behavioral Response in a Spatial Environment ...... 790 Spatial Dynamic of Visual Attention ...... 792 Spatial Constraints on Attentional Automaticity...... 793 Temporal Dynamics of Attention ...... 795 Psychological Time ...... 796 Temporal and Nontemporal Sequencing Mechanisms...... 797 Clocks, Pacemakers, and Quantal Durations ...... 799 Neural Clocks for Behavioral Regulation ...... 800 Short-Duration Timing ...... 802 Short-Duration Neural Clocks ...... 802 Time and Duration Estimation ...... 804 Duration Discrimination Without a Clock ...... 806 Behavioral Timing ...... 808 Timing for Conditioning and Associative Learning ...... 809 Mutual Constraints of Timing and Attention ...... 812 Attention Influences Timing ...... 812 Temporal Influences on Attention ...... 814 Summary ...... 815 References ...... 817 26 Neuroimaging of Attention ...... 829 Functional Neuroimaging of Attention ...... 830 Early Findings ...... 832 Selective Attention ...... 833 Visual Selection ...... 833 Focused Attention and Capacity ...... 837 Executive-Attention ...... 845 Executive-Attention Activation ...... 845 Functional Neuroimaging of Executive Dysfunction ...... 846 Dissociating Executive Component Processes ...... 847 Sustained Attention ...... 849 FMRI Deactivation: The Default Network ...... 850 Neural Recruitment and Compensation ...... 853 Multimodal Neuroimaging of Attention ...... 855 Summary ...... 858 References ...... 859 27 Computational Approaches to Attention ...... 891 Philosophical Issues ...... 892 A Historical Perspective ...... 893 Hypothetico-Deductive Theory...... 893 Contents xxvii

Statistical Learning Theory ...... 897 Psychological Implications ...... 899 Information Theory ...... 900 Connectionist Models of Neural Networks ...... 906 Self-Organizing Systems...... 908 Parallel-Distributed-Processing Framework ...... 909 Activation State: Influence and Determinants ...... 911 Adaptive Resonance Theory ...... 917 Simulation of Visual Attention ...... 919 Current Trends in the Computational Modeling of Attention ...... 921 References ...... 925 28 Neuropsychology of Attention: Synthesis ...... 931 Neural Constraints and Operating Principles ...... 937 Neuropsychological Framework Revisited ...... 939 Structural Constraints on Attention ...... 944 Dynamics of Attention: Information Flow ...... 944 Model of Sensory Selective Attention ...... 947 Model of Executive Attention ...... 949 Focused Attention ...... 951 Neural Mechanisms ...... 951 Frontiers ...... 963 References ...... 963

Index ...... 965