The Study of Spatial Selective Attention Effects by Event-Related Potentials

The effects of visuospatial selective attention on information processing have been investigated by means of high-density event-related brain potentials (ERP) while the subjects were instructed to covertly attend to one side of the visual field with fixation on the center of the screen. Previous studies have demonstrated the attention-related modulation of the P1 (scalp-positive waves from 90-130 ms) and N1 (scalp-negative waves from 160-200 ms) component of ERP recorded from the occipital scalp areas contralateral to the direction of attention. In our study, the additional modulation of the amplitude of P2 component (scalp-positive waves from 220-260 ms) indicates that not only the short-latency early ERP component was affected by spatial attention, but also the late component is modulated, thus it can serve as proof supporting late selection theory.