Programming of endogenous and exogenous saccades: Evidence for a competitive integration model.

Abstract

Participants were required to make a saccade to a uniquely colored target while ignoring the presentation of an onset distractor. The results provide evidence for a competitive integration model of saccade programming that assumes endogenous and exogenous saccades are programmed in a common saccade map. The model incorporates a lateral interaction structure in which saccade-related activation at a specific location spreads to neighboring locations but inhibits distant locations. In addition, there is top-down, location-specific inhibition of locations to which the saccade should not go. The time course of exogenous and endogenous activation in the saccade map can explain a variety of eye movement data, including endpoints, latencies, and trajectories of saccades and the well-known global effect.

Exploring the function of selective attention and hypervigilance for threat in anxiety

“…An individual will execute endogenous saccades towards stimuli that are required for and relevant to the ongoing task, whereas stimuli that capture attention irrespective of the observer's goals and expectations will elicit exogenous saccades (Godijn & Theeuwes, 2002). In a situation where a target and distractor appear simultaneously, for example, goal-directed processes are required to voluntarily inhibit an exogenous saccade to the distractor, thereby increasing the time taken to initiate an endogenous saccade to the target (Godijn & Theeuwes, 2002).…”

Distractor effects on saccade trajectories: a comparison of prosaccades, antisaccades, and memory-guided saccades

“…Whereas saccadic trajectories in most studies, including the studies referred to above, deviate away from a distractor, it has been demonstrated that saccades may also deviate toward a location. For instance, saccadic deviation toward a distractor has been shown in visual search experiments in humans (Godijn and Theeuwes 2002;McPeek et al 2000;Walker et al 2006) and monkeys (McPeek et al 2003;McPeek and Keller 2001;Port and Wurtz 2003).…”

“…Deviations in saccade trajectories are considered to arise from competition between diVerent neural populations during saccade programming, in the same manner that saccade target selection emerges from competitive interactions between populations of neurons coding possible target locations on a common motor map (e.g., Godijn and Theeuwes 2002;Kopecz 1995;Trappenberg et al 2001). While there are multiple parallel routes and areas involved in saccade generation (Schall 1995;Sparks and Hartwich-Young 1989;Wurtz et al 2000), the superior colliculus has often been suggested as the site of this common motor map (e.g., Godijn and Theeuwes 2002;Kopecz 1995;Trappenberg et al 2001).…”

“…While there are multiple parallel routes and areas involved in saccade generation (Schall 1995;Sparks and Hartwich-Young 1989;Wurtz et al 2000), the superior colliculus has often been suggested as the site of this common motor map (e.g., Godijn and Theeuwes 2002;Kopecz 1995;Trappenberg et al 2001). The superior colliculus is topographically organized, in that the locations of neural activity within this structure correspond to speciWc regions in visual space in an orderly arrangement (e.g., Robinson 1972;Schiller and Stryker 1972;Wurtz and Goldberg 1972).…”

“…If so, resolution of unwanted competition between multiple active locations is an important pre-requisite of accurate saccade programming. For example, activity generated by an irrelevant distractor requires inhibition at its location to preserve saccade accuracy (e.g., Godijn and Theeuwes 2002;McSorley et al 2004;Sheliga et al 1994;Tipper et al 2001). As a result, the weighted average of neural populations coding diVerent locations may incorporate both facilitation at the target location and inhibition at the distractor location.…”