Time-course of perceptual processing of "hole" and "no-hole" figures: an ERP study.

Closure or the presence of a "hole" is an emergent perceptual feature that can be extracted by the visual system early on. This feature has been shown to have perceptual advantages over openness or "no-hole". in this study, we investigated when and how the human brain differentiates between "hole" and "no-hole" figures. Event-related potentials (ERPs) were recorded during a passive observation paradigm. Two pairs of simple figures (Experiment 1) and two sets of Greek letters (Experiment 2) were used as stimuli. The ERPs of "hole" and "no-hole" figures differed ∼90 ms after stimulus onset: "hole" figures elicited smaller P1 and N1 amplitudes than "no-hole" figures. These suggest that both P1 and N1 components are sensitive to the difference between "hole" and "no-hole" figures; perception of "hole" and "no-hole" figures might be differentiated early during visual processing.