Figure 2.

Saccadic suppression in an MT neuron. A–D, Response of a single neuron to a stimulus flashed at time 0; each black vertical tick corresponds to a single spike. The diagrams on the right show the screen (black rectangle), the position of the stimulus (yellow bar) on the screen, and the position of the eye (red dot for fixation, red arrow for saccades). A, Response to stimuli flashed long before a saccade. The stimulus is flashed in the receptive field. B, Response to stimuli flashed long after the 20° rightward saccade. These flashes appear in the future field, i.e., the position of the receptive field after the saccade. C, Response to stimuli flashed in the receptive field (RF), in the perisaccadic time window. The time of the saccade is indicated by the red triangles. For this representation, trials were sorted such that the time from stimulus flash to saccade onset was largest for the topmost trial and most negative (i.e., the flash came after the saccade had started) for the bottom-most trial. D, Response to stimuli flashed in the perisaccadic window in the future field (FF). E, Spike density calculated from A–D. The red (blue) curve represents the average response to pre (post)-saccadic stimuli. Green (black) curves represent the response to perisaccadic stimuli flashed in the receptive field as shown in C (future field; D). Solid curves are average responses for flashes presented before the eye started to move [the difference between flash time and saccade onset was in the interval (−75 ms, 0 ms)]. Dashed curves represent the average for flashes presented once the eye has started to move (0 ms, 75 ms). This neuron responded less to perisaccadic than to presaccadic or postsaccadic stimuli; the mechanisms involved in this are a mixture of active and passive processes (for details, see Results).