The late parietal old/new source effects were preceded by prominent mid-frontal old/new effects across tasks and groups, which are likely the CSD equivalent of the mid-frontal ERP recognition memory effects (FN400) repeatedly observed in healthy adults (e.g., Curran, 1999; Curran and Cleary, 2003). Although the overall sink activity on which these early mid-frontal old/new effects were superimposed was greater in controls than patients, there were no significant group differences related to item repetition, which is consistent with our prior findings (Kayser et al., 2009) but in contrast to those reported by Guillem et al. (2001). If the mid-frontal old/new effect is indeed an electrophysiological correlate of item familiarity (e.g., Mecklinger, 2000; Rugg and Curran, 2007), our results suggest preserved implicit knowledge of previous word and face presentations in schizophrenia. However, this generalization should be viewed with caution, given the empirical and interpretational inconsistencies of ERP old/new effects for faces (cf. Curran and Hancock, 2007; Donaldson and Curran, 2007; MacKenzie and Donaldson, 2007, 2009).
