Differentiating neural responses to emotional pictures: evidence from temporal-spatial PCA.

Consistent with the notion that emotional stimuli receive preferential attention and perceptual processing, many event-related potential (ERP) components appear sensitive to emotional stimuli. In an effort to differentiate components that are sensitive to emotional versus neutral stimuli, the current study utilized temporospatial principal components analysis to analyze ERPs from a large sample (N=82) while pleasant, neutral, and unpleasant images were passively viewed. Several factors sensitive to emotional stimuli were identified-corresponding to the N1, early posterior negativity (EPN), and P3; multiple factors resembling the late positive potential (LPP) emerged. Results indicate that the N1 represents the earliest component modulated by emotional stimuli; the EPN and the LPP represent unique components; the scalp-recorded LPP appears to include a P3-like positivity as well as additional positivities at occipital and central recording sites.