The neural mechanisms for visual attention intervene between sensation and action. Neither strictly sensory nor motor, they constitute the neural filters that select certain aspects of visual information for greater attention and influence over action. Visual attention includes mechanisms for arousal, alerting, vigilance, and selective attention for spatial location or visual features. Of these, the ones that most directly affect visual processing are selective attention to a location in space or to a visual feature of an object. These latter mechanisms help route selected visual inputs to visual-processing structures in the brain and also to motor control systems, usually at the expense of nonselected inputs. Behavioral examinations of visual processing, functional-imaging studies in humans, and single-unit studies in the nonhuman primate indicate that selection mechanisms are in play. These experiments aim to understand the influence of attention on the processing of information...