The Spatial Allocation of Visual Attention as Indexed by Event-Related Brain Potentials

Abstract

The spatial distribution of visual attention was studied using event-related brain potentials (ERPs) to index stimulus processing as the locus of attention was shifted across the visual fields. Stimuli were flashed in random order to one of three locations: one in each of the lateral visual fields and one on the vertical meridian. Selective visual-spatial attention was manifested in the ERPs as an amplitude modulation of the sensory-evoked components over frontal, central, parietal, and occipital scalp areas. Attended stimuli also elicited broader negative components that appeared to be endogenous and could be dissociated from the amplitude enhancement of the earlier sensory-evoked components. A gradient of attention was evident in the progressive decline in amplitude of the sensory-evoked components of the ERPs to the lateral stimuli as attention was focused at increasing distances from the stimulus location. These results are discussed in terms of “spotlight” and “gradient” models of the spatial allocation of visual attention.