Attention and active vision.

Visual perception results from the interaction of incoming sensory signals and top down cognitive and motor signals. Here we focus on the representation of attended locations in parietal cortex and in earlier visual cortical areas. We review evidence that these spatial representations are modulated not only by selective attention but also by the intention to move the eyes. We describe recent experiments in monkey and human that elucidate the mechanisms and circuitry involved in updating, or remapping, the representations of salient stimuli. Two central ideas emerge. First, selective attention and remapping are closely intertwined, and together contribute to the percept of spatial stability. Second, remapping is accomplished not by a single area but by the participation of parietal, frontal and extrastriate cortex as well as subcortical structures. This neural circuitry is distinguished by significant redundancy and plasticity, suggesting that the updating of salient stimuli is fundamental for spatial stability and visuospatial behavior. We conclude that multiple processes and pathways contribute to active vision in the primate brain.