Event-related potential correlates of proactive interference in schizophrenic patients and controls

Performance and event-related potentials (ERPs) were examined in a proactiv e interference (PI) task with 15 male schizophrenic patients and 15 matched healthy controls. Within a paired-associate task, 30 pairs of semantically unrelated words (A-B) were presented twice, followed by cued recall, in wh ich the paired-associate B had to be named upon cue A. Subsequently, 50% of the A-words were paired with new words (A-C) and presented in random order together with 15 novel pairings (D-E). Slower responses and poorer recall of C- than of E-words in the final recall indicated PI in both groups. Duri ng acquisition, the paired-associates (C/E) evoked larger P3 and positive s low wave in controls than in patients. During recall, cues (A/D) evoked a s low wave with predominating anterior negativity in controls and posterior p ositivity in patients. The group-specific ERP pattern suggests deviant enco ding and retrieval processes in schizophrenic individuals.