correlate of explicit memory-retrieval processes (conscious recollection), an earlier mid-frontal old/new effect that peaks around 400 ms is regarded as an index of implicit knowledge that a stimulus event has been previously experienced (item familiarity), suggesting different neural generators of two distinct retrieval processes postulated in dual-process models of recognition memory (e.g., Rugg and Curran, 2007; Yonelinas, 2001). Whereas the early mid-frontal old/new effect appears to primarily originate from lateral regions of the prefrontal cortex, the lateral posterior parietal cortex seems to be the main contributor to the late parietal old/new effect (e.g., Yonelinas et al., 2005; Wagner et al., 2005). However, both old/new effects receive contributions from frontal and parietal regions (Iidaka et al., 2006) and MTL structures (Rugg et al., 1991; Guillem et al., 1995; Wegesin and Nelson, 2000) indicative of a more complex recognition memory network. While these positive-going old/new effects overlap either a positive (parietal P3 or P600) or a negative component (mid-frontal FN400, N400, N2) in visual recognition memory tasks, with both ERP topography and polarity affected by the choice of EEG recording reference (cf. Kayser et al., 2003), the different scalp distributions of N2, P3 and the overlying old/new effects strongly suggest that separable
