Repetition and ERPs during emotional scene processing: A selective review.

A set of studies are reviewed that investigate the effects of repetition during scene perception on event-related potentials, elucidating perceptual, memory and emotional processes. Repetition suppression was consistently found for the amplitude of early frontal N2 and posterior P2 components, which was greatly enhanced for massed, compared to distributed, repetition. Both repetition suppression and enhancement of the amplitude of a centro-parietal positive potential (LPP) were found in specific contexts. Suppression was reliably found following a massive number of repetitions of few items, whereas enhancement is found when repetitions are spaced; enhancement was apparent both during simple free viewing as well as on an explicit recognition test. Regardless of repetition, an enhanced LPP was always found for emotional, compared to neutral, scenes. Taken together, the data suggest that different effects of massed and distributed repetitions on specific ERP components index perceptual priming, habituation, and spontaneous episodic retrieval.