Fig. 1.

Visual stimulation and behavioral paradigms. Monkeys were trained to fixate and follow a small red spot on a computer display while a bar of light probed V1 neuron responses. Each frame in the figure depicts the image shown on the screen, the fixation spot, and the position of the receptive field (RF) on the screen (yellow circle; not displayed in the actual experiment). Each panel represents the 2 main epochs within a trial: before (left) and after (right) the stimulus onset or a saccade. A: Flash-on-Gray condition: monkey fixates a red spot in the center of the display (left), and a bar of light is then flashed in the RF (right). B: Saccade-on-Gray: monkey fixates a spot at a peripheral location while the bar is already present (left); the peripheral fixation spot disappears and a new one appears at screen center (right); the monkey makes a saccade to the screen center (small red arrow), bringing the RF onto the bar of light (large red arrow). C: Flash-on-Picture: a natural scene [taken from the van Hateren database (van Hateren and van der Schaaf 1998)] fills the screen, except for a circular buffer patch that encircles the RF; the animal fixates centrally; the stimulus bar is flashed on the buffer. D: Saccade-on-Picture: a natural scene fills the screen except for a circular buffer patch that will encircle the RF after the saccade; the bar is present in the buffer; the animal fixates peripherally (left); the peripheral fixation spot disappears and a new one appears at screen center (right); the monkey makes a saccade to screen center (small red arrow), bringing the RF onto the bar of light (large red arrow). The sizes of the buffer and the bar have been exaggerated for illustration purposes. In practice, the size of the bar was comparable to a small tree branch in the figure. The buffer radius was ∼1.3 times the length of the bar. E: Saccade-on-Picture-NoBar: control condition to test the response produced by the saccade itself; similar to D, but a bar of light was never presented in the buffer. F: Simulated-Saccade: monkey fixates the center of the display during the entire trial; the scene, buffer, and bar move, duplicating the retinal translation that occurs during a real saccade. All figures in this report use the color code established in the panel titles of this figure.