Neural Mechanisms Of Anesthesia

Leading investigators critically evaluate the latest information on how anesthetics work at the molecular, cellular, organ, and whole animal level. These distinguished experts review anesthetic effects on memory, consciousness, and movement and spell out in detail both the anatomic structures and physiological processes that are their likely targets, as well as the cellular and molecular mechanisms by which they operate. Comprehensive and authoritative, Neural Mechanisms of Anesthesia draws together and critically reviews all the recent research on anesthetic mechanisms, highlighting the precise routes along which these substances operate, and how this deeper understanding will lead to the design of effective drugs free ofundesirable side effects.

Sleep and anesthesia resemble in many ways at a first glance. The most prominent common feature of course is the loss of consciousness, i.e. the loss of awareness of external stimuli. However a closer look at the loss of consciousness reveals already a difference between sleep and anesthesia: anesthesia is induced by an anesthetic drug whereas we may fall asleep without external cause. Other questions may arise about the difference of the two effects: do we dream during surgery under anesthesia, do we feel pain during sleep? Essentially, we may ask: what is common and what are the differences between sleep and anesthesia? To answer these questions, we may take a look at the neural origin of both effects and the involved physiological pathways. In which way do they resemble? Moreover, we ask what are the detailed features of normal sleep and general anesthesia as applied during surgery and which features exist in both phenomena? If yes in which way? To receive answers to these questions, it is necessary to consider several experimental techniques that reveal underlying neural mechanisms of sleep and anesthesia. Moreover, theoretical models of neural activity may model both phenomena and comes up with predictions or even theories on the underlying mechanisms. Such models may attack several different description levels, from the microscopic level of single neurons to the macroscopic level of neural populations. Such models may give deeper insight into the phenomena if their assumptions are based on experimental findings and their predictions can be compared to experimental results. This comparison step is essential for valuable theoretical models. The book is motivated by two successful workshops on anesthesia and sleep organized during the Computational Neuroscience Conferences in Toronto in 2007 and in Berlin 2009. It aims to cover all the previous aspects with a focus on the link to experimental findings. It elucidates important issues in theoretical models that at the same time reflect some current major research interests. Moreover it considers some diverse issues which are very important to get an overview of the fields. For instance, the book discusses not only neural activity in the brain but also the effects of general anesthesia on the cardio-vascular system and the spinal cord in the context of analgesia. In addition, it considers different experimental techniques on various spatial scales, such as fMRI and EEG-experiments on the macroscopic scale and single neuron and LFP-measurements on the microscopic scale. In total all book chapters reveal aspects of the neural correlates of sleep and anesthesia motivated by experimental data. This focus on the neural mechanism in the light of experimental data is the common feature of the topics and the chapters. In addition, the book aims to clarify the shared physiological mechanisms of both phenomena, but also reveal their physiological differences.

General anesthesia is a standard medical procedure in today's hospital practice. Although in most cases the administration of anesthetics does not affect severely the patients health, side effects of anesthesia are well-known, such as nausea or cognitive impairment. Moreover 1-2 out of 1000 patients under surgery report a partial wake up from anesthesia during the operation. The reason for such a partial lack of control of depth of anesthesia is that medical procedures are highly optimized based on experience but the neural dynamics during general anesthesia is far from being understood. One reason for this lack of understanding is both the complex neural interactions of neurons on different spatial and temporal scales and the poorly understood action of anesthetics on neural populations. For instance, anesthetic agents act on synaptic receptors on a microscopic scale essentially evoking a macroscopic change of population activity, such as Local Field Potentials, EEG/MEG or resulting change of cerebral blood flow. This population effect then triggers the loss of consciousness in patients. This Research Topic aims to address recent theoretical and experimental advances in the field. The theoretical and experimental studies represent a good overview over the current state of research in the field and provides a deeper insight into the underlying neural mechanisms. Each article in the issue focusses on a specific current research topic in general anesthesia research and several articles introduce to the topic in a pedagogical way. The issue covers various types of anaesthesia and the most important topics in the field, such as (but not limited to) recent advances in theoretical models and states of consciousness reflected in experimental data, the connectivity changes observed during anesthesia or effects of specific drugs on brain activity. The introduction style of the papers facilitates the reader to understand the background of the research aspect and even allows readers not familiar with general anesthesia research to enter the research domain. Hence the Research Topic aims to provide on one hand an overview of the current state of the art and on the other hand a good starting point for new researchers in the field.

Anesthetics produce a reversible state of unconsciousness accompanied by ante- grade amnesia. This remarkable phenomenon brings great relief to surgical patients and wonder to clinicians and scientists. To date, we do not fully understand the mechanisms by which anesthetics ablate conscious sensation and memory. We are, however, making progress. This book presents original results as well as overviews of the current state of knowledge of the problem. It is authored by investigators who know the ?eld well; their research at a number of levels has contributed substantially to our c- rent understanding of anesthetic modulation of memory and consciousness. Most of the contributors were presenters at two workshops organized by Dr. Pearce and Dr. Hudetz at the 40th Annual Winter Conference on Brain Research, held at Snowmass Village, Colorado, from January 27 through February 2, 2007. One workshop focused on anesthetic modulation of consciousness and another on an- thetic modulation of memory. Seven of the chapters are based on material presented at these symposia – appropriately updated with new relevant ?ndings. This infor- tion is supplemented by chapters on anesthesia and sleep, computational analysis of the state of anesthesia, and the clinical phenomenon of “anesthesia awareness,” a topic that has recently received much public attention. With these three additional contributions, the book thus includes 10 chapters.

B. Raymond Fink Sheldon Roth and Keith Miller have asked me to record that the Third Conference on Molecular and Cellular Mechanisms of Anesthesia was held in Calgary last May "in my honor. " Such was my dear friends' gracious way of continuing a series that began at the University of Washington, where I hosted two, four, or five previous ones, 1,3-6 depending 2 on how far back one wishes to count. At that, Seattle took up where Paris left off in 1951. These occasions create their own unforgettable memories. This book captures the fine, invigorating ambience of the University of Calgary and the exciting explorations and com panionship of a gathering in a frontier territory of neuroscience. So, floreant symposia. They have progressively refined the quarry, from pathway to synapse to lipoprotein membrane to receptor and single channel, in heuristic convergences of neuronal physiology, biochemistry, and pharmacology. Nevertheless, the anesthesiologist in me senses a certain disquiet, a certain claustrophobia provoked by the narrow confines of micropipettes. How much more tubular must tunnel vision become before the desired broad view emerges? At present, the advances in molecular neurobiology seem continually to increase the apparent complexity of the total problem and the conceptual distance between the reductionists in the laboratories and the holists in the operating rooms. Happily, what is also growing is the excitement in trying to bridge the gap. Perhaps it would be timely to regard general anesthesia not as a state but as a syndrome.

The perioperative care of individuals with neurologic compromise is critically important, yet it is only one dimension of the rich relationship between anaesthesiology and the neurosciences. The mechanism of everyday therapeutic interventions such as anaesthesia and analgesia is exciting neuroscience in its own right. At the new frontier of outcomes studies lies the question of how the perioperative period might impact the brain. For example, questions related to anaesthetic neurotoxicity, delirium, and cognitive dysfunction pose critical challenges for the field. The Oxford Textbook in Neuroscience and Anaesthesiology addresses the exciting field of neuroanaesthesiology in a new and stimulating way. In twenty eight chapters, the neuroscientific basis of anaesthesiology, the full spectrum of clinical neuroanaesthesia, and the care of neurologic patients undergoing non-neurologic surgery are explored in one comprehensive textbook for the first time. The first section considers the neural mechanisms of general anaesthetics, cerebral physiology, the neurobiology of pain, and more. The second section explores the care of patients with neurologic disease in the operating room or intensive care unit. These clinical chapters systematically treat the perioperative considerations of both brain and spine surgery, and provide introductions to neurocritical care and pediatric neuroanaesthesia. The final section outlines the care of neurologic patients undergoing non-neurologic surgery. It examines key connections of neurology and anaesthesiology, examining how conditions such as dementia, stroke, or epilepsy interface with the perioperative period. Each chapter has been carefully crafted to be concise yet highly informative, reflecting the cutting edge of neuroscience and neuroanaesthesiology. This international textbook gathers the best available expertise of authors and leaders worldwide. Includes access to online-only content, including more than 20 cases and more than 90 questions that can be used in presentations and teaching sessions. By activating your unique access code, you can access and use the material.

Although the perioperative care of patients by anesthesiologists draws on diverse clinical skills, the principles of anesthesiology and pain management are rooted in the neurosciences. The Neuroscientific Foundations of Anesthesiology thoroughly examines the anesthetic modulation of the central, peripheral, and autonomic nervous systems and will help redefine anesthesiology as a fundamentally neuroscientific field. The book is organized by sections, with each focusing on a different part of the nervous system. State-of-the-art chapters written by thought-leaders in anesthesiology and neuroscience provide a novel and invaluable resource.