Memory: a guide for anaesthetists.

Episodic memory is the most 'human' of all memory systems, is integrally related to the hippocampus, and not only permits memories of the past in rich detail, but also allows projection of thoughts into the future. However, episodic memory is very sensitive to anaesthetic drugs and cannot be formed during adequate general anaesthesia. Ablation of episodic memory during consciousness is due to forgetting of memories, rather than inhibition of memory formation. There is a fine balance between being conscious with recollection and conscious with no recollection. A more detailed understanding of episodic memory in relation to other memory systems, as well as the relationship of the hippocampus to episodic memory function is provided. A synthesis of diverse knowledge is undertaken to identify potential mechanisms of amnesic drug effect, which will, of course, require further research to delineate.