Feature-based attention influences motion processing gain in macaque visual cortex

Changes in neural responses based on spatial attention have been demonstrat ed in many areas of visual cortex(1-4), indicating that the neural correlat e of attention is an enhanced response to stimuli at an attended location a nd reduced responses to stimuli elsewhere. Here we demonstrate non-spatial, feature-based attentional modulation of visual motion processing, and show that attention increases the gain of direction-selective neurons in visual cortical area MT without narrowing the direction-tuning curves. These find ings place important constraints on the neural mechanisms of attention and we propose to unify the effects of spatial location, direction of motion an d other features of the attended stimuli in a 'feature similarity gain mode l' of attention.