Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study

Abstract

Event Abstract Back to Event Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study Amity E. Green1*, Paul B. Fitzgerald1, Patricia T. Michie2, Pradeep J. Nathan3, 4 and Rodney J. Croft5, 6 1 Monash Alfred Psychiatry Research Centre, Monash University and the Alfred Hospital, Australia 2 University of Newcastle, School of Psychology, Australia 3 School of Psychology and Psychiatry, Monash University, Australia 4 Brain Mapping Unit, Department of Psychiatry, University of Cambridge, United Kingdom 5 Illawarra Health & Medical Research Institute, University of Wollongong, Australia 6 School of Psychology, University of Wollongong, Australia Aims: Individuals with schizophrenia demonstrate pronounced deficits in cognitive processing with particular impairments in episodic memory. This may reflect a difficulty in the ability to encode new information. The subsequent memory paradigm has been used in the study of memory formation to segregate neural processes responsible for successful encoding. In healthy controls subsequently remembered items are associated with a more positive ERP waveform than those later forgotten. The aim of the study was to investigate neural correlates of encoding in schizophrenia using a subsequent memory paradigm. Method: EEG was recorded in 20 patients and 19 healthy controls during the semantic encoding of single words. ERPs were sorted according to whether words were subsequently recognised. Group differences were determined in late positivity (LPP; area under the curve 450-750ms), as well as for N1, P2 and N400 ERP peak amplitudes, as a function of subsequent recognition. Results: Patients tended to perform poorer than controls on the recognition test (slower [p=0.069] and less accurate [p=0.006]). Mean amplitude of the encoding-related LPP was greater for recognised than not-recognised words (p=0.035, eta-squared=0.12), with patients showing reduced mean amplitude compared to controls regardless of whether the word was recognised (p=0.018, eta-squared=0.15). Further, compared to controls, patients showed significantly reduced P2 (p=0.032, eta-squared=0.11) and frontal N400 peak amplitudes (p=0.012, eta-squared=0.15) during encoding. Conclusions: The results suggest that reduced activation of encoding processes contributes to poorer recognition memory performance in schizophrenia, however the relative importance of early attentional (P2) and later sematic processing (N400 and LPP) alternations cannot be determined from the present study. Acknowledgements This research was funded by the National Health & Medical Research Council of Australia, Project Grant #502910 Keywords: Schizophrenia, episodic memory, encoding, event-related potential (ERP), susbsequent memory paradigm Conference: ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology, Wollongong, Australia, 20 Nov - 22 Nov, 2013. Presentation Type: Poster Presentation Topic: Memory Citation: Green AE, Fitzgerald PB, Michie PT, Nathan PJ and Croft RJ (2013). Neural Correlates of Successful Encoding in Schizophrenia: An Event-Related Potential Study. Conference Abstract: ASP2013 - 23rd Annual meeting of the Australasian Society for Psychophysiology. doi: 10.3389/conf.fnhum.2013.213.00023 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Oct 2013; Published Online: 05 Nov 2013. * Correspondence: Ms. Amity E Green, Monash Alfred Psychiatry Research Centre, Monash University and the Alfred Hospital, Melbourne, Australia, amity.green@monash.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Google Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Google Scholar Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft PubMed Amity E Green Paul B Fitzgerald Patricia T Michie Pradeep J Nathan Rodney J Croft Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.