How we recall (or don't): the hippocampal memory machine and anesthetic amnesia

The hippocampal formation occupies a central position for the processing of sensory input into learned, remembered, and consciously retrievable information. The mechanisms by which anesthetic drugs interfere with these processes are now emerging. We review the current understanding of the role of the hippocampal formation in the generation of memory traces and how anesthetics might interfere with its function.

Intraoperative amnesia is a desired endpoint of general anesthesia from the perspective of both the patient and the practitioner. "Intraoperative awareness with recall" can result when learning and memory do occur. In addition, anesthetics are capable of inducing a state of "conscious amnesia" that can provide insight into the workings of the brain and might be useful clinically.

Anesthesiologists routinely induce the most fascinating pharmacologic effects in existence, the reversible interference of anesthetics with higher cognitive functions. Understanding how the drugs in our custody exert their effects should be our contribution to mankind's universal knowledge base.