Attention, Neural Basis of

Abstract

Typically, our environment contains many different objects, but the capacity of our nervous system to fully analyze them is limited. At any given time, only a small amount of the total sensory input is actively taken up for further processing. Several lines of evidence indicate that multiple object representations compete for processing resources in a mutually suppressive fashion. These competitive interactions take place in multiple brain systems, sensory and motor, and can be biased in favor of relevant information as a result of selective attention. Selective mechanisms appear to operate as top-down signals that modulate sensory processing in several ways: enhancement of neural response to an attended stimulus, suppression of ignored-object representations, and shift of baseline activity in the absence of sensory stimulation. Depending on the current task, spatial and nonspatial features can be used to give a competitive advantage and processing resources to objects of relevance. A main source of top-down biasing influence may derive from frontal and parietal structures involved in working memory and motor preparation.