[...]... last? 1.4 Organization and contents of the book 1.5 Summary References 1.1 Purpose of the handbook Since 1990, the field of neuroprosthetics has grown at a tremendous rate But, what exactly is meant by the term neuroprosthetics, and why are neuroprostheses of such consuming interest? For the purposes of this handbook, a neuroprosthetic is a device or system that does one of the following: ©2003 CRC Press... much of the functionality of the nervous system as possible 1.1.1 Why a handbook on neuroprosthetics? The rapidly expanding interest and research in neuroprosthetics over the last decade paralleled the rapid increase in resources and literature devoted to the larger fields of bioengineering and biomedical engineering A quick search of the Internet finds over 50 academic institutions with departments of. .. Chapter nine, the problem of using neural signals in neuroprosthetic device design is addressed A description of several different neuroprosthetic systems and their development is the subject of Section V Chapter ten details the state of the relatively more mature field of otological implants for hearing rehabilitation, while Chapter eleven details the ongoing development and challenges of visual prostheses... descriptions of ion channel function generally fall within two categories: gating and permeation Gating describes the temporal dependence of the opening and closing of a channel and the probability of finding a channel in an open or closed state as a function of membrane potential or the presence of a drug or neurotransmitter Permeation describes the conductive properties of a channel in terms of its selectivity... resting potential, often with a brief period of “after hyperpolarization” during which the membrane potential is made more negative than the resting value The time course of an action potential varies, with most mammalian neurons firing spikes having a half-width of well under 1 msec Physiologists studying the problem of cellular excitability were aware of the different ionic compositions of the intra- and... References 2.1 Introduction The purpose of this chapter is to provide an understanding of how ion channels produce membrane excitability The neuroprosthetic theories and devices described in this book depend to varying degrees on the excitability of neural membranes and on the function of many different types of voltagegated ion channels The overall problem is that neuroprosthetic devices, such as retinal... very day (see Chapter three).4 Based on a series of experiments on squid axons, Hodgkin and Huxley developed a physiological model of neuron behavior at an unprecedented level of detail In particular, the model illuminated the process of action-potential generation, detailing the roles of membrane potential and ionic currents The work also described unique methods for controlling and recording neural signaling... architectures matured, experiments requiring simultaneous monitoring of multiple signals became feasible This led to new discoveries such as the concerted signaling in the retina that offers clues to the processing of visual images.5 The combination of affordable microprocessors and VLSI led to one of the most important tools at the disposal of modern researchers, the affordable personal computer The first... growth of artificial neuronal networks, explore the impact of implants on cell pathology, and actually view the tiny microelectrodes and similar devices, just for starters Assays such as these provide invaluable information on the behavior of nerves and neurons and their interaction with foreign implants that improve the design of the next generation of devices and systems 1.2.2.2 First successes in neuroprosthetics... host of technologies and extensive research have built upon the earlier developed tools to fuel this explosion in neuroprosthetics The continued miniaturization of all forms of electronics, from cameras to processors to the electrodes themselves, has made it more feasible to communicate with larger numbers of nerves and neurons, therefore providing finer control over motor functions and finer sampling of . 0-8493-1100-4 Library of Congress Card Number 2002031437 Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Printed on acid-free paper Library of Congress Cataloging-in-Publication Data Handbook of neuroprosthetic. contents of the book 1.5 Summary References 1.1 Purpose of the handbook Since 1990, the field of neuroprosthetics has grown at a tremendous rate. But, what exactly is meant by the term neuroprosthetics . environment, without the benefit of a common vocabulary, a common set of methods for approaching problems, or a common set of analytical and experimental tools. Yet, methods and concepts from all of these areas