Temporal neural dynamics of the competition between extrinsic and intrinsic grouping principles in vision: an ERP study.

Abstract

Previous research has explored the brain correlates of perceptual grouping but, to our knowledge, no preceding study has investigated the neural dynamics of the competition between intrinsic and extrinsic grouping principles in vision. The present event-related potentials (ERPs) study aimed at characterizing the temporal neural dynamics of the direct competition between extrinsic (i.e., common region) and intrinsic (i.e., shape similarity) grouping cues. In separated blocks, participants selectively attended and responded to perceptual clusters based on one of the two grouping cues pitted against each other in a competing condition, which was compared to a uniform, non-grouped condition. Behavioural results indicated larger interference effect of common region over shape similarity cues when both grouping principles competed against each other, supporting a processing dominance of common region. Applying a temporo-spatial principal component analysis (PCA), our ERP data showed four main neural correlates related to perceptual grouping and competition between grouping cues: (1) an enhanced central-posterior N195 associated with perceptual dominance of common region cues during the visual analysis of perceptual grouping; (2) an enhanced posterior P245 presumably reflecting higher confidence in perceptual decisions linked to common region grouping; (3) a posterior P400 possibly indexing the differential allocation of attentional resources related to higher processing efficiency of common region cues; and (4) a P550 that seems to be related to top-down suppression activity for the termination of the current trial.