Abstract
We investigated whether saccade target selection and the allocation of spatial attention are represented within the same or separate attentional maps. In two experiments a spatial location was cued either endogenously or exogenously. Participants either attended at the cued location ("Attention-only condition"), made a saccade to instructed location ("Saccade-only condition"), or attended at the cued location and made a saccade to instructed location ("Dual-location condition"). We measured the allocation of attention (to the cued and the saccade target location) using an orientation discrimination task. Competition between cued location and saccade target location should arise if attentional resources for the two are shared, and no competition should occur if resources are independent. The results from the endogenous cue task indeed revealed a competition between cued and saccade target location, as evidenced by impaired orientation discrimination performance in the dual-location condition. Additionally, we observed that saccade trajectories curved away from the cued location, suggesting a competition between saccade target and cued location within the oculomotor system. In contrast, in the exogenous cue task, there was no impairment of attentional allocation to both, cued and saccade target locations, suggesting the independent, parallel allocation of attentional resources to both locations. Furthermore, curvature of saccade trajectory was smaller, indicating only minor competition between saccade target and cued location within the oculomotor system. Our findings challenge the idea that a unitary priority map is used to guide saccades and attention. We suggest that while endogenous attention and saccade target selection seem to be represented within the same attentional map, the priority map that is related to exogenous attention is separate and its interactions with the saccadic system are limited. Combined, our findings suggest that multiple attentional maps can represent attentional targets, each of them having different access to the saccadic system.
Meeting abstract presented at VSS 2013