Global effects of feature-based attention in human visual cortex.

The content of visual experience depends on how selective attention is distributed in the visual field. We used functional magnetic resonance imaging (fMRI) in humans to test whether feature-based attention can globally influence visual cortical responses to stimuli outside the attended location. Attention to a stimulus feature (color or direction of motion) increased the response of cortical visual areas to a spatially distant, ignored stimulus that shared the same feature.