Posts Tagged ‘Brain’

The Human Brain

The Human Brain

Paul Glees

New York, Cambridge University Press, 1988. 204 pp.

In his most recent book, The Human Brain, Paul Glees, Emeritus Professor of Neuroanatomy and Histology at the University of Gottingen, attempts to expand upon two of his earlier works (Das Menschliche Gehrin [1968] and Experimental Neurology [1961]). As the author states, the book draws upon his “experience and accumulated teaching material,” especially his recent teaching experiences at Cambridge University. Although the book is relatively short, its approach to neurobiology is strikingly comprehensive. Glees places great emphasis on anatomy (human and comparative), embryology, and histology, but there are also numerous small pockets of neurophysiology and neuropathology, with occasional clinical correlations. Much of the first part of the book, in particular, is written for the novice in neurobiology. Its style is simple, with an emphasis on basics. There are many interesting figures and drawings; the first 20 pages of the book contain 30 figures. Despite the often simple style, it is one of the rare books which may be read on several levels, and its figures contain large quantities of valuable information.

The book possesses a number of strengths, the first being its evolutionary approach to neurobiology. This approach is particularly apparent in chapters one and two. Thus, there is a significant amount of comparative anatomy, and the reader gains a sense of the development of the human brain over time. The phylogenetic approach, missing from most books, provides this one with added value. The above-mentioned evolutionary/phylogenetic approach extends to the author’s explanations for the relative development of certain brain structures. These explanations tend to have a teleological flavor, making them somewhat simplistic, though often intriguing. While the author’s evolutionary approach often gives the reader additional information, at times the information is incorrect. Thus, Figures 2.1 and 2.12 contain major paleo-anthropological errors. For example, David Pilbeam’s work in the Siwalik hills has demonstrated that the sivapithecines were probably an early form of orangutan rather than early hominids. Moreover, Paranthropus, a taxonomic term applied to the robust South African australopithecines, is a term that was largely abandoned in the early 1950-s as a result of the work of Le Gros-Clark, S.L. Wasburn, and others. These errors may be attributed, in part, to the author’s references, which are rapidly becoming outdated (e.g., De Beer’s Bildatlas der Evolution [1964], Howells’ Early Man [1966], Day’s Guide to Fossil Man [1967], and Le Gros-Clark’s History of Primates {1958]).

For the most part, the book is comprehensive and well organized, containing 14 chapters on subjects ranging from the peripheral nervous system (”Touch, pain and proprioception”) to the central nervous system (”The cerebral hemispheres,” “The brainstem and cerebellum”). The chapter which deals with neuroglia is particularly interesting; it is here, perhaps more than at any other point in the book, that the author divulges some of his knowledge and tremendous expertise.

Apart from the volume’s scattered grammatical errors, sentences are often convoluted and difficult to understand. It is unclear whether this flaw may be attributed to the author’s style or to the nature of the translation; however, some passages are misleading, a particularly worrisome fault in a book intended for novices. For instance, the following sentence implies that there is no cardiopulmonary circulation: “As already emphasised in the section on brain metabolism, the supply of nourishment originating in the liver reaches the brain via the vascular system.” Furthermore, there are quite a few errors in the book’s figures (e.g., in Figure 7-6, CA, cerebral aqueduct, is labeled AC, anterior commissure; in Figure 7-7, dln, dorsolateral nucleus, is labeled ins, insular cortex).

Despite these relatively minor flaws, this book distinguishes itself because of the organization, wealth of information, and evolutionary and teleological approaches. Most notable, however, is the fact that it may be read on multiple levels. For this reason, I would recommend The Human Brain to a broad audience, either as an introduction to the field of neurobiology or to reacquaint the reader with the basics and to gain a different (that is, teleological) perspective.

Vision and the Brain

Vision and the Brain: Organization of the Central Nervous System

Edited by Bernard Cohen and Ivan Bodis-Wollner

New York, Raven Press, 1990. 364 pp.

While experimenting with retinal ganglion cells of cats in 1966, Enroth-Cugell and Robson made one of the major breakthroughs of the century in vision research. They showed that these cells, capable of firing action potentials, are organized in relation to simple receptive fields on the retina centralis. This work pioneered the ongoing effort to understand how light-induced signals are graded, distributed, and processed from the retina to the thalamus to the cortex (and within the cortex), making visual function possible. Vision and the Brain: Organization of the Central Nervous System, edited by Bernard Cohen and Ivan Bodis-Wollner, attempts to bring the reader up to date on the latest research in this fascinating and dynamic field.

Vision and the Brain is volume 67 in a series published by the Association for Research in Nervous and Mental Disease. The organization has been sponsoring a new volume about once a year since 1920. Vision and the Brain is the product of 37 authors, and contains 161 illustrations. It is drawn from the authors’ original works and compiled from eighteen papers, each complete with a set of references. The volume is supplemented with an extensive index.

Vision and the Brain reads more like a textbook than a collection of many authors’ writings. In general, each chapter provides a clear and concise overview of the topic under consideration that the non-expert can easily understand and appreciate. This overview is followed by descriptions of potential domains of research as well as a summary of the authors’ pioneering work in the field. The book begins with a thorough examination of the functional and pharmacological organization of retinal cells. Here, much attention is given to the horizontal cell and the role of dopamine as a modulator of lateral inhibition — a phenomenon that aids in the visual recognition of edges. Next, the authors discuss the different transmitters mediating systems within the lateral geniculate nucleus, thus summarizing the pre-cortical processing of visual input.

Most of the book is dedicated to describing the complex interpretation of images at the level of the cortex. A summary of the encoding of objects in their shapes, color, movement, and depth is provided in an enjoyable chapter which explains some of the rationale behind optical illusions. This material is followed by a detailed analysis of neural velocity field computation, recognition of facial expression, motion processing, and the coordination of eye movement. An interesting discussion of the use of positron emission tomography to help map visual cortex functioning is also included.

For the neurology student, this book can be an amusing and up-to-date summary of visual processing systems. For the clinician, it also sheds light on the visual disturbances associated with such conditions as Parkinson’s disease, Altzheimer’s disease, and multiple sclerosis. For the vision researcher, it serves as a convenient collection of some of the field’s pioneering work. In any case, it comes with a hefty price tag.

Stress, the Aging Brain, and the Mechanisms of Neuron Death

Stress, the Aging Brain, and the Mechanisms of Neuron Death

Robert M. Sapolsky

Cambridge, M., The MIT Press, 1992.429 pp

Does stress kill brain cells, and if so, how? In Stress, The Aging Brain, and Mechanisms of Neuronal Death, Dr. Robert Sapolsky presents data supporting the disturbing notion that psychological stresses may be associated with chemical processes in the brain that subject neurons to toxic processes. Dr. Sapolsky’s research, which has taken him from the African veldt to the neurobiology laboratory, provides a framework to orient readers to this interesting review.

In a well-crafted presentation, Dr. Sapolsky integrates his highly original research with related topics of great interest to neuroscientists, neurologists and psychiatrists. He takes care to review hot issues, such as the impact of glucocorticoids on brain function, the role of N-methyl-D-aspartate (NMDA) receptors in learning and neurotoxicity, and the function of nitric oxide as a mediator of NMDA receptor function. In a particularly creative step, Dr. Sapolsky bridges the traditional neuropharmacologic focus on neuro-modulation and the study of energy regulation within neurons during neuromodulation. He presents evidence to support the hypothesis that elevated glucocorticoid levels associated with stress deplete neuronal energy, making them less capable of fending off the toxic effects of inotropic excitatory amino acid receptor stimulation and its associated increase in calcium influx.

As the product of four years of work and “everything (he) knows as of January 10, 1992,” this book contains a prodigious amount of information presented in a thoughtful and user-friendly fashion. It is evident that Dr. Sapolsky has considered challenges facing the reader. Each chapter begins with a review of the book to that point and finishes with a summary of concepts presented within the chapter. These efforts make the text more accessible and enhance its utility as a reference source. In a scientific world dominated by least publishable units and multi-authored texts, Dr. Sapolsky succeeds in developing his views on stress and neurotoxicity in depth with an informal and somewhat socratic style. This stylistic approach makes the large body of information presented more engaging to the reader.

Dr. Sapolsky acknowledges the limitations of his book, occasionally, as they appear in the text. He reviews rapidly evolving fields of research. As a result, significant developments have already occurred in some areas of study reviewed in this book. Also, clinical perspectives on the type of stresses that push neurons “to the brink” could be developed further. The notion that routine social stresses might increase neuronal loss during a seizure is less formidable than the hypothesis that these stresses are neurotoxic in the absence of a medical crisis. One might also have appreciated a more thorough discussion of psychological trauma and its aftermath.

Overall, this is a very good book for researchers in many areas of clinical and basic neurosciences. It serves as a good entry point for researchers and clinicians interested in the areas of stress, neuroactive corticosteroids, excitatory amino acids, and neurotoxicity. Researchers well-versed in these areas may benefit from Dr. Sapolsky’s novel evaluations of a broad range of data and the numerous and intriguing hypotheses presented.

The Brain Atlas

The Brain Atlas: A Visual Guide to the Human Central Nervous System

Thomas A. Woolsey, Joseph Hanaway, and Mokhtar H. Gado

Fitzgerald Science, 2002. 249 pp

As a student learning neuroanatomy, one of the biggest challenges is often mastering the blood supply to any given region of the central nervous system. The most user-friendly approach to learning such information can now be found within the second edition of The Brain Atlas by Woolsey et al. from the Washington University School of Medicine. Even as one picks up the manual, the brilliant colors and easy to flip notebook style bring the atlas to life as an appealing teaching guide. For every tissue section through the brain and spinal cord, one can easily follow clearly numbered anatomical regions: from a histological photograph to a colorful representation of the vascular supply and lastly to an in situ view through a MR image. The atlas ends with an emphasis on all of the major Central Nervous System (CNS) pathways by superimposing brightly labeled pathways upon actual histological sections from the brain to the lower spinal cord levels. This “one glance reveals all” approach is not only a major time-saver, but also depicts the pathways more clearly than any other reference I have ever encountered.

The logical, multi-disciplinary progression in The Brain Atlas succeeds beautifully in integrating the anatomical, radiological, vascular, and functional aspects of neuroanatomy just as a student would be expected to know in a clinical setting. Furthermore, the clearly delineated sections make this an easy and fast reference on the wards for any student or resident. One possible improvement for future editions might be the inclusion of actual clinical syndromes as they apply to normal anatomy, vascular supply, and pathways. The Brain Atlas is clearly a valuable asset to any student, teacher, or clinician broaching the wonderful world of neuroscience.