A spatiotemporal principal component analysis of recognition memory ERPs to emotional and neutral faces

Johansson, M., and Mecklinger, A.
Experimental Neuropsychology Unit, Department of Psychology, Saarland University, Germany
E-mail: m.johansson@mx.uni-saarland.de

Previous behavioral and event-related potential (ERP) research have suggested that emotion may exert an influence on memory accuracy as well as on the subjective state of awareness accompanying recognition. The present study used a spatiotemporal principal component analysis (PCA) approach to investigate old/new memory effects for positive, negative, and neutral faces and emotion-specific modulations in the ERPs. The factors extracted in an initial spatial PCA were subjected to a second temporal PCA to obtain spatiotemporal factor combinations. The results reveal midfrontally distributed factors coding for old-new differences for all emotion types within a 300-600 ms time window and additional posteriorly distributed factors for negative faces. Specifically, the old/new effect for negative faces were associated with an early occipital (~400 ms) and a somewhat later parietal (~600 ms) spatiotemporal factor. Emotion-specific modulations were observed predominately over midfrontal regions in a time window similar to the frontal old/new effects. The present results are in accord with view that negative valence may act to facilitate the formation and/or retrieval of bound memory representations making negative stimuli recollected to a greater extent than positive and neutral stimuli. Supported by the German Research Society (grant FOR448).