Dr. Mesulam and colleagues offer an extensively revised edition of their seminal behavioral neurology textbook, Principles of Behavioral Neurology (F.A. Davis, 1985). The first edition is an exceptionally clear summary of the fundamental concepts and syndromes in behavioral neurology, and it is widely regarded as essential reading for practitioners, researchers, and educators in behavioral neurology and neuropsychiatry. It has remained extremely instructive and useful despite the many advances in basic and clinical neurosciences since its publication in 1985. In particular, the connectionist approach to structural and functional neuroanatomy, and the understanding of neurobehavioral disorders that this approach facilitates, is truly a principle of behavioral neurology that endures as discoveries in the basic and clinical neurosciences continue.
In the 15 years since the publication of the first edition, scientific progress in the neurosciences has been both remarkable and relentless. In the preface to the present work, Dr. Mesulam explains that the advances in functional neuroimaging in particular, and the insights into brain—behavior relationships that such advances afforded, prompted the revision of this textbook.
Functional neuroimaging of neurologically impaired patients substantively improved investigations of the neurobiological bases of disordered cognition, emotion, and behavior and permitted similar investigations of normal functions in neurologically intact subjects. Dr. Mesulam also suggests that the development of flexible, widely available, high-quality functional neuroimaging strengthened the alliance between behavioral neurologists, neuropsychologists, neuropsychiatrists, and cognitive neuroscientists, making the work of each more similar to that of the others. Now and in the future, he suggests, the behavioral neurologist will be a cognitive neuroscientist, and vice versa. To reflect this suggestion, the title of the second edition is Principles of Behavioral and Cognitive Neurology.
In general, the present work revises, refines, and extends the information contained in the first edition. An exception to this approach is the deletion of chapters on electrophysiology, basic functional neuroimaging, and quantitative approaches to computed tomography. Information regarding the first two of these topics is included elsewhere in the text where relevant. A general familiarity with such methods (e.g., EEG, evoked potentials, fMRI, SPECT, PET) is assumed, and hence specific chapters reviewing these methods are not presented. The topic of quantitative CT imaging, now obsolete in light of quantitative magnetic resonance imaging, is understandably omitted.
This book is likely to be challenging for students, residents, and fellows, given the familiarity with neuroanatomy, neurophysiology, neuroimaging, and neurobehavioral patients it assumes in readers, the scope and depth of the material covered in its 10 chapters, and the complexity inherent in this material. Trainees may benefit substantially from this book as part of a supervised curriculum by educators familiar with its contents and with the application of the principles presented to the care of patients.
In chapter 1, "Behavioral Neurology: Large-scale Networks, Association Cortex, Frontal Syndromes, the Limbic System, and Hemispheric Specializations," Dr. Mesulam significantly expands the scope and depth of the introduction. The chapter emphasizes synaptic "levels"— connections within a processing stream, the connections between processing streams to form networks, and the interactions between multiple networks that establish one or another cognitive capacity. Also expanded is the discussion of processing channels and state/modulatory systems, hemispheric specialization, and large-scale networks and their cortical epicenters. Particular emphasis is given to discussion of the networks subserving face and object recognition, motor function, language, and emotion-memory. To that end, the description of the limbic system is significantly elaborated in the present edition, substantially improving the value of this chapter. Illustrations are used extensively, and an update of Dr. Mesulam's excellent rendering of the overlap between Brodmann areas and functional neuroanatomy is provided. This chapter is substantial enough to stand alone as a monograph, but in context it provides a framework that is consistently followed in subsequent chapters.
Chapter 2, "Neuropsychological Assessment of Mental State" (S. Weintraub), offers a detailed discussion of the neuropsychological methods used to assess the cognitive and behavioral domains discussed the first chapter. Information on bedside assessment of cognition, emotion, and behavior is now embedded in the relevant sections within this chapter, in contrast to the first edition in which this information was presented in a separate section. Specific neuropsychological tests and procedures are presented in a table outlining the relationship between these tests and the primary domains they are designed to assess. As presented here, this chapter may be of particular value to neuropsychologists engaged in such assessments.
Chapter 3, "Attentional Networks, Confusional State, and Neglect Syndromes" (M.-M. Mesulam), is a much-expanded version of the comparable chapter in the first edition. The discussion of the theory and neurobiology of attention and related disorders is masterful. The chapter elegantly moves from descriptions of clinical syndromes of impaired attention to discussion of the selective distributed networks underlying attentional processes. A central concept in this chapter is that of the attentional matrix and its three principal functional/modulatory compartments: modality- and domain-specific, bottom-up (ascending reticular activating system), and top-down (prefrontal, parietal, and limbic). The large-scale networks that "permit mental representation of experience to transcend surface appearance and become sensitive to behavioral relevance" are described in detail. Additional emphasis on right hemisphere dominance for spatial attention is discussed, and a large-scale distributed network with cortical epicenters in the posterior parietal cortex, frontal eye fields, and cingulate gyrus is outlined. The interaction between these networks in the service of developing intrapersonal and extrapersonal awareness is briefly discussed.
Chapter 4, "Memory and Amnesias" (H.J. Markowitsch), is a substantial rewrite and improvement of the chapter bearing the same name in the first edition. Of particular note is the detailed and entirely helpful discussion of the nosology of memory and its constituent functions (also presented in tabular form). The inclusion of functional neuroimaging data, as well as several elegant line drawings of the neuroanatomic substrates of memory, further improves on the previous version. As with other chapters in this text, a network approach to memory functions is offered, and data suggesting hemispheric specialization for various aspects of memory are presented.
Chapter 5, "Aphasia and the Neural Basis of Language" (A. R. Damasio and H. Damasio), is substantially different in both content and style from its counterpart in the first edition. Based on recent functional neuroimaging research in this area (including the authors' own), a revised neuroanatomy of language and language dysfunction is presented. The authors challenge the frequently presented but overly simplistic framework in which Wernicke's and Broca's areas and arcuate fasciculus connecting them are the key elements in the language network. Their discussion is supported by several functional neuroimaging figures to illustrate the presence of several overlapping networks associated with language for certain specific kinds of objects or actions. In the service of this detailed discussion, several other topics included in the counterpart chapter of the first edition (alexia, agraphia, anomia, apraxia, acalculia, and Gerstmann's syndrome) are now discussed separately and more briefly elsewhere in this edition.
Chapter 6, "Affective Prosody and the Aprosodias" (E.D. Ross), offers a succinct description of these topics. In contrast to the first edition, the present chapter offers a more concise discussion of prosody and kinesics, their neurobiology, and their disturbances. The affective and gestural components of the aprosodias are presented in tabular form, and the "language areas" (right hemisphere homologues of the language areas described in Chapter 5) subserving prosody are illustrated clearly. The author also offers a cautionary note regarding the need to consider aprosodias in patients presenting with discrepancies between mood and demeanor; this point may be the most important clinical lesson in this chapter for practicing clinicians.
Chapter 7, "Disorders of Complex Visual Processing" (A. R. Damasio, D. Tranel, M. Rizzo), is an updated and substantially expanded version of the chapter presented in the first edition of this work. Discussion of the neural networks subserving complex visual processing is offered, including those subserving face recognition, perception of facial emotion, social knowledge, implicit recognition of familiar faces despite prosopagnosia, cortical blindness, Anton's syndrome, pure alexia, disorders of color perception and naming, Bálint's syndrome, constructional ability, and dressing ability.
Chapters 8, 9, and 10 describe a number of clinical problems in behavioral neurology, including temporolimbic epilepsy, primary psychiatric disorders, and aging and dementia, respectively. The content of these chapters, and particularly the final chapter on aging and dementia by Dr. Mesulam, appears to be designed to describe the neurobiology of these common and challenging clinical problems and simultaneously to illustrate the application of principles of cognitive and behavioral neurology presented in the preceding chapters. Among these, the final chapter (also by M.-M. Mesulam) illustrates superlatively the utility that the connectionist framework affords for better understanding dementia of the Alzheimer's type, the various frontotemporal dementias, diffuse Lewy body disease, mild cognitive impairment, and the cognitive consequences of normal aging.
In summary, Principles of Behavioral and Cognitive Neurology is an exceptional contribution to the clinical neuroscience literature. Much like its predecessor, this edition should be regarded as essential reading for behavioral neurologists, neuropsychiatrists, and neuropsychologists. All of the chapters in this edition are of the highest quality, as would be expected from the world-renowned experts that contributed to this work. The chapters by Dr. Mesulam are masterworks of scientific writing, integrating what is presently known about the neural networks subserving cognition with the highest level of modern theorizing in this area. These chapters eloquently describe and synthesize the spectacular advances in basic and clinical neuroscience in the 15 years since publication of the first edition of this work. Dr. Mesulam notes in the preface that the ongoing development of anatomical, electrophysiological, imaging-based, and computational methods to explore the connectivity of the human brain will almost undoubtedly advance significantly our understanding of the human brain over the next decade. I hope that at end of another decade (or sooner), Dr. Mesulam will again recruit his panel of experts to provide another edition of this seminal work.
Dr. Arciniegas is Director of the Neuropsychiatry Service and Assistant Professor of Psychiatry and Neurology, University of Colorado Health Sciences Center, and Research Associate Physician, Denver Veterans Affairs Medical Center, Denver, CO.