Central nervous system physiology in anaesthetic practice

Abstract

How and where consciousness is generated and maintained remains an unsolved scientific mystery, and this has impeded progress in understanding anaesthesia. In recent years, however, significant progress has been made in understanding the neurobiology of anaesthetic-induced loss of consciousness. This has been made possible by advances in molecular biology techniques, which have helped shed light on the molecular mechanisms of action of the anaesthetic agents. In parallel, the development of neuroimaging techniques, such as functional magnetic resonance imaging and positron emission tomography, has also provided an enormous impetus. These techniques are providing new insights into the neural correlates of consciousness, and new insights into the alterations in neurophysiology associated with impaired consciousness caused by sleep, sedation, and anaesthesia. The information being gained from these studies on the neurobiology of impairments of attention, awareness, and memory will hopefully eventually not only lead to improvements in our understanding of consciousness and anaesthesia, but also to better clinical care. Understanding of memory functions during sedation and anaesthesia may, for example, lead to better strategies for preventing awareness with subsequent explicit recall of intraoperative events. Further, a better understanding of the neurobiology of anaesthetic-induced unconsciousness may inform future development of better anaesthetic agents, with a broader therapeutic index, and fewer unwanted effects.