Topographic Mapping of Brain Electrical Activity presents the state of topographic mapping. It discusses its contributions to brain research. It addresses its research and clinical applications. It also explains completely the brain electrical activity mapping as a tool used in the diagnosis and treatment of neurological dysfunction Some of the topics covered in the book are the color imaging of scalp somatosensory evoked potential fields; visual evoked potential topography; spatial analysis of EEG and evoked potential data; intra-individual changes in EEG during mental performance; and changes in transversal coherence. The event-related desynchronization mapping of visualization of cortical activation patterns is fully covered. The spatiotemporal mapping display is discussed in detail. The text describes in depth the physical aspects of EEG data as a basis for topographic mapping. The human scalp field injection experiments are presented completely. A chapter is devoted to the classification strategies for topographic mapping data. Another section focuses on the topological factors. The book can provide useful information to radiologists, neurologists, students, and researchers.

Imaging procedures have been used for many years and are becoming increasingly important in a number of medical disciplines. This is due to recent technological advances, primarily computerization. The meth ods employed in CNS diagnostics are collectively referred to as "neu roimaging" and include procedures for investigating both cerebral morphology and cerebral function, such as computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomogra phy (PET), and single-photon emission computed tomography (SPECT). Topographic mapping of electroencephalograms (EEG) and evoked potentials represents one of the functional procedures and per mits topographic imaging of EEG, evoked potentials, and magnetic fields. The latter application includes not only magnetic fields evoked by stimuli relating to different sensory modalities, but also endogenous and motor fields resulting from spontaneous brain magnetic activity, as recorded by magnetoencephalograms (MEG), the magnetic comple ment of the EEG. The advantage of recording electric and magnetic fields over other neuroimaging procedures is that these techniques are completely noninvasive and have extremely short analysis times (in the millisecond range). The aim of this book is to clarify the current state of this emerging technology, to assess its potential for substantive contributions to brain research, to delineate areas for further research and, over all, to envis age clinical applications in disciplines such as psychiatry, neurology, and neuropsychology.

Electroencephalography is truly an interdisciplinary endeavor, involving concepts and techniques from a variety of different disciplines. Included are basic physics, neuro physiology, electrophysiology, electrochemistry, electronics, and electrical engineer ing, as well as neurology. Given this interesting and diverse mixture of areas, the train ing of an EEG technician, a neurology resident, or an EEG researcher in the basics of clinical electroencephalography presents an uncommon challenge. In the realm of technology, it is relatively easy to obtain a technically adequate EEG simply by learning to follow a protocol and by correctly setting the various switches on the EEG machine at the right time. But experience has shown that the ability to obtain high-quality EEGs on a routine, day-to-day basis from a wide variety of patients requires understanding and knowledge beyond what is learned by rote. Likewise, knowledge above and beyond what is gained by simple participation in an EEG reading is necessary to correctly and comprehensively interpret the record. Such knowledge comes from an understanding of the basic principles upon which the practice of clinical EEG is founded - principles that derive from the various disciplines cited.

It had been difficult to find appropriate teaching material for students and newcomers to this field of brain electromagnetic topography. In part, this is due to the many disciplines involved, requiring some knowledge of the physical sciences, mathematics, neurophysiology and anatomy. It is my hope that this book will be found suitable for introducing interested workers to this exciting field. Advanced topics will not be covered, as there are many excellent texts available. Peter K.H. Wong vii ACKNOWLEDGEMENT My co-authors, Hal Weinberg and Roberto Bencivenga, for their support; Richard Hamer, for all his early advice; Ernst Rodin and Gene Ramsay, for their encouragement; Wendy Cummings for her assistance; Technologists from the Department of Diagnostic Neurophysiology for collecting such excellent data; Bio-Logic Systems Corp. for permission to use some data as illustration; and all my friends and colleagues. My wife Elke, for putting up with me throughout this presumptuous endeavour. The manuscript was delivered in camera-ready form to the Publisher. Illustrations were created using Harvard Graphics and CorelDraw software. ix CONTENTS Part 1: Fundamentals. 1 1.1 Introduction . . . 1 1.2 Data Aquisition. . 3 Map Construction. 8 Interpolation . . . 12 1.3 Spatial Sampling . . 16 1.4 Reference and Reference-Dependence 20 1.5 Map Display Methods ..... . 27 Scaling and Floating Voltage Scales. 37 Summary Maps .......... . 37 1.6 Identification of Topographic Features 41 1.7 Spike Mapping .. . 51 1.8 Post-Processing 61 Analog Front-end. 62 Digital Filtering . 63 Reference Manipulation .. 65 Statistical Mapping .

The leading reference on electroencephalography since 1982, Niedermeyer's Electroencephalography is now in its thoroughly updated Sixth Edition. An international group of experts provides comprehensive coverage of the neurophysiologic and technical aspects of EEG, evoked potentials, and magnetoencephalography, as well as the clinical applications of these studies in neonates, infants, children, adults, and older adults. This edition's new lead editor, Donald Schomer, MD, has updated the technical information and added a major new chapter on artifacts. Other highlights include complete coverage of EEG in the intensive care unit and new chapters on integrating other recording devices with EEG; transcranial electrical and magnetic stimulation; EEG/TMS in evaluation of cognitive and mood disorders; and sleep in premature infants, children and adolescents, and the elderly. A companion website includes fully searchable text and image bank.

From its discovery in 1929 by Hans Berger until the late 1960s, when sensory visual and auditory evoked potentials were dis covered and became popular, the EEG was the most important method of neurophysiological examination. W-ith the advent of computer technology in the 1980s, it became possible to plot the potential fields of the EEG onto models of the scalp. This plot ting of information as neuroimages followed the structural and functional techniques of Cf, MRI, PET and SPECf. The success of this method, which began in the early 1980s, has led to the brain mapping of EEGs and EPs being increasingly used for di agnosistic purposes in neurology, psychiatry and psychopharma cology. The pioneers of this method believed in it and were commit ted to its success. However, many traditionalists felt that it gave no new information and so regarded the method with scepticism. Some found both the coloured maps and the mapping technique misleading, which led to unnecessary conflict between mappers and their chromophobic oponents. Emotions have run so high that some professional bodies have justifiably adopted guidelines and warned of the misuse of the method.

Although cerebral dominance, the specialization of each side of the brain for different functions, was discovered in the 1860s, almost nothing was known for many years about its biological foundations, the study of which has undergone what can only be described as a revolution in the past decade and a half. Norman Geschwind and Albert Galaburda, two of the leaders of this new field, have assembled a distinguished group of investigators, each a pioneer in some aspect of the biology of dominance. The authors document human brain asymmetry at gross and microscopic levels in both adults and fetuses, its visualization in life by radiological methods, and its manifestation in brain waves. The evolutionary history of brain asymmetry over more than 300,000 years is shown in fossil skulls of humans and apes. In a dramatic reversal of older beliefs, asymmetry of anatomy, function, and chemistry has been demonstrated in many nonhuman species, and experiments have shown the role of hormones and other prenatal influences in the production of asymmetry. The surprising associations of non-right-handedness with twinning and immune disorders are discussed, as well as the asymmetrical malformation of the cortex in childhood dyslexia. This volume, combining scholarly authority and the excitement of the birth of a new discipline, will be welcomed by those to whom the implications of dominance are becoming evident--neuroscientists, neurologists, linguists, psychologists, experts in learning disorders, speech pathologists--and by specialists in nearly every branch of biology, medicine, and psychology.

Cognitive electrophysiology is a very well established field utilizing new technologies such as bioelectric events-related potentials (ERP) and magnetic (ERF) recordings to pursue the investigation of mind and brain. Current research focuses on reviewing ERP/ERF findings in the areas of attention, language, memory, visual and auditory perceptual processing, emotions, development, and neuropsychological clinical damages. The goal of such research is basically to provide correlations between the structures of the brain and their complex cognitive functions.This book reviews the latest findings in the areas of attention, language, memory, visual and auditory perception, and brain damage research based primarily on research conducted using ERP recordings. Beyond just compiling the knowledge gained from ongoing research, the authors also identify outstanding problems in the field and predict future developments. - Provides an original post-cognitive theoretical approach to the investigation of the human mind and brain - Presents integrated view of the emotional and cognitive features as well as of developmental features of neurocognitive systems - Well-illustrated with elegant and original artwork that clarifies complex theoretical and methodological points throughout the text

Evoked potentials are potentials that are derived from the peripheral or central nervous system. They are time locked with an external stimulus and can be influenced by subjective intentions. Evoked potentials have become increasingly popular for clinical diagnosis over the last few years. Evoked potentials from the visual system are used by ophthalmologists in order to localize the abnormalities in the visual pathway. The otologists are mainly involved in brainstem auditory evoked potentials, while the pediatricians, neonatologists, neurologists and clinical neurophysiologists make use of multimodal stimulation. The psychiatrists and psychologists, generally, examine the slow potentials such as P300 and CNV. Anesthesiologists use short latency somatosensory and visual evoked potentials in order to monitor the effectiveness of the anesthesia. Pharmaco evoked potentials are very promising measures for the quan tification of the effectiveness of drug action on the cerebral cortex. Urologists are more and more involved in pudendal somatosensory evoked potentials and in the intensive care unit evoked potentials are used in order to monitor the functional state of the central nervous system of the patient. This overwhelming number of examinations and exam ina tors clearly demonstrates the need for guidelines and standardization of the methods used. The evoked potential metholody is restricted by the relative poor signal to noise ratio. In many diseases this signal to noise ratio decrease rapidly during the progression of the illness. Optimal technical equipment and methodology are therefore essential.