Cognitive task release the eyes

Abstract

In an earlier study, Trottier and Pratts (2005 Vision Research 45 1349 ^ 1354) hypothesized that, during a saccade task toward a peripheral target, the instruction can act as a top-down disinhibition of the superior colliculus and therefore reduce the saccadic latencies. Using another paradigm (a cue preceding the appearance of the target) we replicated their results and showed the same effect with prosaccades and a kind of antisaccades. Saccade latencies were shorter when people were instructed to not simply look at a target (glance) but to identify some of its properties (identification). We compared this effect to the classical gap effect and showed differences that are supposedly mediated by different cerebral mechanisms. Preliminary data with an agnosic patient who does the identification task at a chance level show the same strong effect of the task on saccade latencies. The patient did not make saccades when the target appeared to the left side of the screen during the glance task, whereas he did it for the identification task. The task appears to have a strong effect.