The study of patients with memory deficits is the most significant cause to explore the structure and organization of memory system.
Memory refers to the acquisition, storage and retrieval of information. The brain achieves these three aspects of memory by associating neural representations with one another. In this way, organisms learn the causal relationships of the world by exposure to events, continually adjusting and augmenting their internal representations when learned associations do not match reality. Virtually all views of learning share this common thread, from simple conditioning paradigms to cognitive theories.1
A common mechanism does not imply a single, monolithic memory system. Such a view was dispelled long ago by observations of spared and impaired learning abilities in patients with hippocampal damage.2 Modern theories of learning typically divide memory into multiple psychological systems supported by different neural sub-states. From a psychological perspective, different systems learn different kinds of information, performing their functions for different lengths of time. From a biological perspective, memory systems are interconnected neural structures suited to particular information processing demand, either storing information or participating in its storage in other structures. Similarities between these perspectives are presumed to reflect the same phenomena at different levels of analysis, where observations from one perspective serve to validate those of the other.3
Virtually all experimental paradigms for the study of memory reveal specialized components serving different functions. Even basic, associative conditioning involves multiple memory systems, as the cerebellum, hippocampus and amygdala are known to contribute differentially to classically conditioned responses. A multiple memory s