The spatial coding of the inhibition evoked by distractors

Abstract

It is generally agreed that saccade deviations away from a distractor location represent inhibition in the oculomotor system. By systematically manipulating the location of a distractor we tested whether the inhibition of the distractor is coded coarsely or fine-grained. Results showed that the location of a distractor had an effect on the saccade trajectories, suggesting that the amount of inhibition observed depends on the location of the distractor. More specifically, the vertical distance of the distractor from fixation seems to be a determining factor. These findings have important implications for models that account for inhibition in the target selection process and the areas that could underlie inhibitory influences on the superior colliculus (SC), like the frontal eye fields (FEF) and the dorsolateral prefrontal cortex (dlPFC). Finally, the initial direction and the endpoint of a saccade were found to be strongly correlated, which contradicts recent models proposing that the initial saccade direction and saccade endpoint are unrelated.