Fast Oscillations In Cortical Circuits

In Fast Oscillations in Cortical Circuits, the authors use a combination of electrophysiological and computer modeling techniques to analyze how large networks of neurons can produce both epileptic seizures and functionally relevant synchronized oscillations.

This book reviews a number of clinical neuropsychiatric conditions in which brain oscillations play an essential role. It discusses how the intrinsic properties of neurons, and the interactions between neurons - mediated by both chemical synapses and by gap junctions - can lead to oscillations in populations of cells.

This book first reviews the case that brain oscillations not only are important for cognition, as long suspected, but also play a part in the expression of signs and symptoms of neuropsychiatric disorders. The cellular mechanisms of many of the clinically relevant oscillations have been studied by the authors and their colleagues, using in vitro slice methods as well as detailed computer simulations. A surprising insight is that gap junctions between principal neurons play an absolutely critical role in so many types of oscillation in neuronal populations; oscillations are not just the result of properties of individual neurons and their synaptic connections. Furthermore, the way in which gap junctions produce oscillations in the cortex is novel, involving as it does global properties of networks, rather than just the time constants of membrane currents. This insight has implications for therapeutics as well as for our understanding of normal brain functions.

Neurophysiologists are often accused by colleagues in the physical sci ences of designing experiments without any underlying hypothesis. This impression is attributable to the ease of getting lost in the ever-increasing sea of professional publications which do not state explicitly the ultimate goal of the research. On the other hand, many of the explicit models for brain function in the past were so far removed from experimental reality that they had very little impact on further research. It seems that one needs much intimate experience with the real nerv-. ous system before a reasonable model can be suggested. It would have been impossible for Copernicus to suggest his model of the solar system without the detailed observations and tabulations of star and planet motion accu mulated by the preceeding generations. This need for intimate experience with the nervous system before daring to put forward some hypothesis about its mechanism of action is especially apparent when theorizing about cerebral cortex function. There is widespread agreement that processing of information in the cor tex is associated with complex spatio-temporal patterns of activity. Yet the vast majority of experimental work is based on single neuron recordings or on recordings made with gross electrodes to which tens of thousands of neurons contribute in an unknown fashion. Although these experiments have taught us a great deal about the organization and function of the cor tex, they have not enabled us to examine the spatio-temporal organization of neuronal activity in any detail.

Research on brain oscillations and event-related electroencephalography (EEG) and event-related (de-) synchronization (ERD/ERS) in particular became a rapidly growing field in the last decades. A large number of laboratories worldwide are using ERD/ERS to study cognitive and motor brain function and the importance of this tool in neurocognitive research is widely recognized. This book is a summary of the most current research, methods, and applications of the study of event-related dynamics of brain oscillations. Facing the rapid progress in this field, it brings together, on the one side, fundamental questions of the underlying events, which still remain to be clarified and, on the other side, some of the most significant novel findings, which point to the key topics for future research. In particular, the chapters of this volume cover the neurophysiological fundamentals and models (Section I), new methodological approaches (Section II), current ERD research related to cognitive (Section III) and sensorimotor brain function (Section IV), invasive approaches and clinical applications (Section V), and novel developments of EEG-based brain-computer interfaces and neurofeedback (Section IV).

Epilepsy research has entered an exciting phase as advances in molecular analysis have supplemented in vitro and in vivo electrophysiologic and phenotypic characterization. Recent Advances in Epilepsy Research sets forth a series of chapter reviews by researchers involved in these advances. This volume is a composite profile of some exciting recent investigations in select areas of enquiry. Key features: neurogenetics of seizure disorders, new developments in cellular and molecular neurobiology of seizure disorders, the role of growth factors in seizures, new advances in the roles of metabotropic glutamate receptors and GABA receptors and transporters, gap junctions, neuroimmunology of epilepsy, malformations of cortical development, neurogenesis, new animal models of epilepsy and the use of brain stimulation to treat epilepsy. This book should be of interest to a wide variety of audiences, including graduate students in neurobiology and related disciplines, neuroscientists, medical students, neurologists, neurosurgeons, and industry including pharmaceutical companies and medical device companies. There are many ideas in this book that will lead ingenious innovators in academia and industry to develop new and better therapies.

This book presents thoroughly revised tutorial papers based on lectures given by leading researchers at the 8th International Summer School on Neural Networks in Erice, Italy, in October/November 2003. The eight tutorial papers presented provide competent coverage of the field of cortical dynamics, consolidating recent theoretical and experimental results on the processing, transmission, and imprinting of information in the brain as well as on important functions of the cortical area, such as cortical rhythms, cortical neural plasticity, and their structural basis and functional significance. The book is divided in two topical sections on fundamentals of cortical dynamics and mathematical models of cortical dynamics.