Studies of comprehension, memory and recall during sedation. (360G-Wellcome-083660_Z_07_Z)

The principal research objective is to elucidate how anaesthetic drugs interfere with cognitive functions (such as attentiveness, memory and processing of auditory stimuli) during sedation. We will use functional MRI and continuous EEG monitoring to identify these effects in volunteers sedated with propofol, nitrous oxide or sevoflurane. We will aim to ascertain the role of the inferior frontal cortex in the resolution of semantic ambiguities during the sedated state. Painful stimuli during seda tion and anaesthesia are associated with arousal activity in the brain; we will attempt to identify the influence of such stimuli on the inferior frontal cortex. These data will help establish whether anaesthetic agents interfere with cognitive function during sedation by interfering with the brain's ability to maintain attentiveness, by interfering with individual perceptive processes, or by interfering with the ability of the brain to pass information between different regions and then bind th e whole into a unified conscious experience. This could potentially lead to an improved understanding of anaesthesia, and consciousness, and may inform the development of practical, EEG based methods of detecting awareness during anaesthesia. These studies will also provide important insights into the hierarchy of cortical language processing.