ERP correlates of recognition memory: effects of retention interval and false alarms

Within the framework of the dual process model of recognition memory, prior work with event-related potentials (ERPs) has suggested that an early component, the FN400, is a correlate of familiarity while a later component, the Late Positive Complex (LPC), is a correlate of recollection. However, other work has questioned the validity of these correlations, suggesting that the FN400 effect is too short-lived to reflect an explicit memory phenomenon and that the LPC may be influenced by decision-related factors. Using a Remember/Know paradigm we addressed these issues by (1) examining the effect of study-test delay on correctly recognized items associated with familiarity ('Know' responses) and recollection ('Remember' responses) and by (2) examining FN400 and LPC modulation associated with false alarms. Supporting the relationship of the FN400 with familiarity, attenuation of this component was present for 'Know' responses relative to correct rejections after both the short (39 min) and long (24 h) delay conditions. Attenuation of the FN400 also occurred for false alarms (responses largely driven by familiarity) relative to correct rejections. Although an increased LPC amplitude was found associated with 'Remember' responses at both delays, a decreased LPC amplitude was observed with false alarms relative to correct rejections. This latter result is discussed with regard to the possibility of an overlapping posterior negativity.