Neural correlates of prospective and retrospective memory.

This study examines the event-related brain potential (ERP) correlates of retrieval processes in prospective and retrospective memory (i.e., recognition and cued-recall). In contrast to previous research that has compared performance on tasks measuring prospective and retrospective memory, the stimulus materials and encoding and response demands of the prospective and retrospective components of the tasks were reasonably well matched for the two forms of memory. This resulted in the primary difference between the assessments of prospective and retrospective memory being the requirement for self-initiated retrieval in prospective memory. Analyses of mean amplitude measures revealed modulations of the ERPs typically associated with prospective memory (i.e., N300 and prospective positivity) and retrospective memory (i.e., FN400, parietal positivity and frontal slow waves). Partial least squares analyses revealed one latent variable related to the retrieval of a previously studied item that contrasted retrospective hits and prospective hits from ongoing activity trials and prospective lures; and one latent variable uniquely associated with prospective hits. These findings indicate that similar neural processes support retrieval in prospective and retrospective memory and that the realization of intentions is additionally dependent on processes that are uniquely related to prospective memory.