Focal inactivation of the monkey superior colliculus causes a location-specific deficit in sustained spatial attention. A) Monkeys were cued by a red circle to attend to the direction of a pulse of coherently moving dots and to report the direction of motion (red arrow) with an eye movement in the corresponding direction. They were trained to ignore both the orthogonally directed, coherent motion in the diagonally opposite quadrant (foil stimulus; yellow arrow) and the random motion in the neighboring quadrants. Blue: the region of the visual field affected by the inactivation. B) Eye saccade responses before SC inactivation. C) Eye saccade responses to the same stimulus configuration after SC inactivation. D) Comparison of responses before versus after SC inactivation when the cued stimulus was located within the inactivated portion of the visual field. E) Comparison of responses before versus after SC inactivation when the cued stimulus was located outside of the inactivated portion of the visual field. Modified from Lovejoy and Krauzlis, 2010.