COGNITIVE NEUROSCIENCE AND NEUROPSYCHOLOGYThe P600 reflects cost of new information in discourse memoryBurkhardt, PetraAuthor Information University of Marburg, Marburg, Germany Correspondence to Dr Petra Burkhardt, University of Marburg, Department of Germanic Linguistics, Wilhelm-Röpke-Strasse 6a, D-35032 Marburg, Germany Tel: +49 6421 2824645; fax: +49 6421 2824558; e-mail: [email protected] Received 31 July 2007; accepted 30 August 2007 NeuroReport: November 19, 2007 - Volume 18 - Issue 17 - p 1851-1854 doi: 10.1097/WNR.0b013e3282f1a999 Buy Metrics Abstract Discourse processing depends on long-term semantic memory and discourse memory (i.e. the organization and maintenance of a mental model). Using event-related potentials, the information-processing functions of the activities manifested by a centroparietal negativity (N400) and a posterior positivity (P600) were investigated during the processing of inferences. On the basis of findings from semantic priming, it was predicted that the standard N400 signature would modulate differences in the degree of inferential processing (semantic memory). Instead of N400 modulations, however, the two conditions that depended on a more demanding drawing of inferences elicited a P600, indicating that updating the mental model encumbers discourse memory capacity. The results highlight the functional significance of this positivity for discourse updating, and support the view that the P600 reflects distinct language processes. © 2007 Lippincott Williams & Wilkins, Inc.