ABSTRACT
Visually guided saccades reorient our gaze to objects in the visual field. Only one saccade is executed at a time, even when there are several potential targets present simultaneously in the visual field. Upon target fixation, saccades can be released or not released at will. Moreover, the timing of visually guided saccades depends on the behavioral context in which they are released. As first described by Fischer and colleagues,1‚2 the probability of occurrence of saccades called express due to their extremely short (80 to 120 ms) reaction time (SRT), dramatically increases when a time gap lasting for a few hundred milliseconds (gap period) separates the time when the stimulus being fixated is turned off and a new stimulus, the saccade target, is turned on. Therefore, it is reasonable to think that the neural processes that determine when and where to make saccades engage components of brain circuits responsible for decision making (for review see Reference 3).
