Erp Correlates of Spatiotemporal Regularity in Vision

Spatiotemporal regularities in stimulus structure have been shown to influence visual target detection and discrimination. Here we investigate whether the influence of spatiotemporal regularity is associated with the modulation of early components (P1/N1) in Event-Related Potentials (ERP). Stimuli consisted of five horizontal bars (predictors) appearing successively towards the fovea followed by a target bar at fixation, and participants performed a key-press on target detection. Results showed that compared to the condition where five predictors were presented in a temporally regular but spatially randomised order, target detection-times were faster and contralateral N1 peak latencies were shorter when the predictors and the target were presented with spatial and temporal regularity. Both measures were most prolonged when only the target was presented. In this latter condition, an additional latency prolongation was observed for the P1 peak compared to the conditions where the target was preceded by the predictors. The latency shifts associated with early ERP components provides additional support for involvement of early visual processing stages in the coding of spatiotemporal regularities in humans.