ERP correlates of item recognition memory: Effects of age and performance

Decline in episodic memory is a common feature of healthy aging. Event-related potential (ERP) studies in young adults have consistently reported several modulations thought to index memory retrieval processes, but relatively limited work has explored the impact of aging on them. Further, work with functional imaging has demonstrated differential neural recruitment in elderly subjects depending on their level of cognitive performance which may reflect compensatory or, alternatively, inefficient processing. In the present study we examined the effect of aging and level of performance on both early (FN400, LPC) and later [late frontal effect (LFE)] ERP indices of recognition memory. We found that the FN400 and LPC were absent or attenuated in the older group relative to young adults, but that the LFE was actually increased, analogous to findings in the functional imaging literature. Additionally, the latter effect was most prominent in the poorer performing older participants. These findings suggest that weak memory retrieval supported by earlier ERP modulations, may lead to an enhanced LFE in the service of additional retrieval attempts

ERP correlates of remember/know decisions: association with the late posterior negativity

Abstract A number of studies have utilized the Remember/Know paradigm to determine event-related potential (ERP) correlates of recollection and familiarity. However, no prior work has been specifically directed at examining the processing involved in making the Remember/Know distinction. The following study employed a two-step recognition memory test in which participants first decided whether they recognized a word from a prior study list (Old/New decision); if they did, they then determined whether it was recognized on the basis of recollection ('Remember' responses) or familiarity ('Know' responses). By time-locking ERPs to the initial Old/New decision, processing related to making the introspective Remember/Know judgment was isolated. This methodology revealed a posterior negativity that was largest for 'Remember' responses. Previous work has described a late posterior negativity which appears to be related to the search for and recapitulation of study details. Such processing may be critical in making Remember/Know determinations.