ERP old/new effects at different retention intervals in recency discrimination tasks.

Recognition memory studies have suggested that event-related brain potentials (ERPs) may tap into several different memory processes. In particular, two ERP components have been hypothesized as related to familiarity (FN400 old/new effect, 300-500 ms, anterior) and recollection processes (parietal old/new effect, 400-800 ms, posterior). The functional significance of the FN400 old/new effect is uncertain because similar old/new differences have been shown to disappear at moderately long retention intervals. The present study investigated the effects of retention interval (34 min, 39 min, or 1 day) on the FN400 and parietal old/new effects in two different recency discrimination tasks. The results suggest that the FN400 old/new effect can be maintained across 1-day retention intervals, so it may index brain processes capable of contributing to long-term memory.