Psychophysiology, 34(4):414-426, 1997.
Event-related potential (ERP) asymmetries to emotional stimuli in a visual half-field paradigm
Jürgen Kaysera,b, Craig Tenkeb, Helge Nordbyc, Dag Hammerborgc, Kenneth Hugdahlc, Gisela Erdmanna
a Institute of Psychology, Technical University of Berlin, Germany
b Department of Biopsychology, New York State Psychiatric Institute, New York, NY, USA
c Department of Biological and Medical Psychology, University of Bergen, Norway
Received 9 April 1996; accepted 13 November 1996; published 1 July 1997; published online 30 January 2007
Abstract
To investigate the hypothesis of a right hemispheric superiority in negative emotional processing, event-related potentials (ERPs) were recorded from 17 sites (Fz, Cz, Pz, F3/4, F7/8, C3/4, T7/8, P3/4, P7/8, 01/2) in a visual half-field paradigm. While maintaining fixation. right-handed women viewed pictures of patients with dermatological diseases before (negative) and after (neutral) cosmetic surgery. A principal components analysis with Varimax rotation performed on ERPs revealed factors identified as N1, N2, early P3, late P3, and slow wave. Repeated measures analyses of variance performed on factor scores revealed a significant effect of emotional content for ail factors except for N1. However, asymmetries in emotional processing were restricted to N2 and early P3, with maximal effects over the right parietal region. N2-P3 amplitude was augmented for negative and reduced for neutral stimuli over right hemisphere regions. Visual field presentation interacted with these asymmetries in enhancing amplitudes contralaterally for early but ipsilaterally for late ERP components. Overall, findings for N2 and P3 support theories of an asymmetry in emotional processing.
Keywords: Event-related potentials (ERPs); Laterality; Emotion; Visual half-field paradigm; N2-P3 amplitude; Principal components analysis (PCA)