VISUAL REPRESENTATIONS DURING SACCADIC EYE-MOVEMENTS

In normal vision, shifts of attention are usually followed by saccadic eye movements, Neurons in extrastriate area V4 are modulated by focal attention when eye movements are withheld, but they also respond in a dvance of visually guided saccadic eye movements. We have examined the visual selectivity of saccade-related responses of area V4 neurons in monkeys making delayed eye movements to receptive field stimuli of va rying orientation. This task did not require the monkey to attend to o rientation per se but merely to foveate the receptive field stimulus. We present evidence that the presaccadic enhancement exhibited by V4 n eurons, quite separate from the response at stimulus onset, is a resur gent visual representation that seems as selective as the response is when the stimulus first appears. The presaccadic enhancement appears t o provide a strengthening of a decaying featural representation immedi ately before an eye movement is directed to visual targets. We suggest that this reactivation provides a mechanism by which a clear percepti on of the saccade goal can be maintained during the execution of the s accade, perhaps for the purpose of establishing continuity across eye movements.