The role of lateral prefrontal cortex in working memory: Evidence from event-related fMRI studies

Working memory refers to the short-term storage of information that is not accessible in the environment, and the set of processes that keep this information accessible for maintenance and manipulation for later use in behavior. In this review, we will present data from a series of event-related fMRI studies of delayed-response tasks that were designed to investigate the role of different regions of the lateral prefrontal cortex (PFC) during different working memory component processes. From this data, we conclude that lateral PFC activity cannot be ascribed to the function of a single, unitary cognitive operation but rather lateral PFC is anatomically organized according to the types of cognitive operations that one performs when attempting to temporarily maintain and manipulate information. Moreover, consistent with the picture that has emerged from the monkey electrophysiological literature, human lateral PFC is involved in several encoding, maintenance and response-related processes that are likely to be critical for guiding and controlling behavior.