Wollenberg Luca, Deubel Heiner, Szinte Martin
Allgemeine und Experimentelle Psychologie, Ludwig-Maximilians-Universität München; Graduate School of Systemic Neurosciences, Ludwig-Maximilians-Universität München;
Allgemeine und Experimentelle Psychologie, Ludwig-Maximilians-Universität München.
J Vis Exp. 2019 Mar 18(145). doi: 10.3791/59162.
This experimental protocol was designed to investigate whether visual attention is obligatorily deployed at the endpoint of saccades. To this end, we recorded the eye position of human participants engaged in a saccade task via eye tracking and assessed visual orientation discrimination performance at various locations during saccade preparation. Importantly, instead of using a single saccade target paradigm for which the saccade endpoint typically coincides roughly with the target, this protocol comprised the presentation of two nearby saccade targets, leading to a distinct spatial dissociation between target locations and saccade endpoint on a substantial number of trials. The paradigm allowed us to compare presaccadic visual discrimination performance at the endpoint of accurate saccades (landing at one of the saccade targets) and of averaging saccades (landing at an intermediate location in between the two targets). We observed a selective enhancement of visual sensitivity at the endpoint of accurate saccades but not at the endpoint of averaging saccades. Rather, before the execution of averaging saccades, visual sensitivity was equally enhanced at both targets, suggesting that saccade averaging follows from unresolved attentional selection among the saccade targets. These results argue against a mandatory coupling between visual attention and saccade programming based on a direct measure of presaccadic visual sensitivity rather than saccadic reaction times, which have been used in other protocols to draw similar conclusions. While our protocol provides a useful framework to investigate the relationship between visual attention and saccadic eye movements at the behavioral level, it can also be combined with electrophysiological measures to extend insights at the neuronal level.
本实验方案旨在研究视觉注意力是否在扫视的终点被强制性地部署。为此，我们通过眼动追踪记录了参与扫视任务的人类参与者的眼睛位置，并在扫视准备期间评估了不同位置的视觉方向辨别性能。重要的是，该方案不是使用单一扫视目标范式（其扫视终点通常大致与目标重合），而是包括呈现两个相邻的扫视目标，这导致在大量试验中目标位置和扫视终点之间存在明显的空间分离。该范式使我们能够比较准确扫视（落在其中一个扫视目标上）终点和平均扫视（落在两个目标之间的中间位置）终点的扫视前视觉辨别性能。我们观察到准确扫视终点处视觉敏感性有选择性增强，而平均扫视终点处则没有。相反，在执行平均扫视之前，两个目标处的视觉敏感性均有同等增强，这表明平均扫视是由于扫视目标之间未解决的注意力选择所致。这些结果与基于扫视前视觉敏感性的直接测量而非扫视反应时间（在其他方案中用于得出类似结论）的视觉注意力与扫视编程之间的强制性耦合观点相悖。虽然我们的方案为在行为层面研究视觉注意力与眼球扫视运动之间的关系提供了一个有用的框架，但它也可以与电生理测量相结合，以扩展在神经元层面的见解。
