Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan; Cognitive Intelligence and Precision Healthcare Center, National Central University, Taoyuan City, Taiwan.
Institute of Cognitive Neuroscience, National Central University, Taoyuan City, Taiwan; Faculty of Electronics Engineering, Posts and Telecommunications Institute of Technology, Ho Chi Minh City, Viet Nam.
Neuroscience. 2021 Nov 10;476:90-101. doi: 10.1016/j.neuroscience.2021.09.014. Epub 2021 Sep 24.
Saccades are rapid eye movements that are used to move the high acuity fovea in a serial manner in the exploration of the visual scene. Stimulus contrast is known to modulate saccade latency and metrics possibly via changing visual activity in the superior colliculus (SC), a midbrain structure causally involved in saccade generation. However, the quality of visual signals should also be modulated by the amount of lights projected onto the retina, which is gated by the size of the pupil. Although absolute pupil size should modulate visual signals and in turn affect saccade responses, research examining this relationship is very limited. Besides, pupil size is associated with motor preparation. However, the role of pupil dilation in saccade metrics remains unexplored. Through varying peripheral background luminance level and target visual contrast in the saccade task, we investigated the role of absolute pupil size and baseline-corrected pupil dilation in saccade latency and metrics. Higher target detection accuracy was obtained with lower background luminance level, and larger absolute pupil diameter correlated with smaller saccade amplitude and higher saccade peak velocities. More interestingly, the comparable modulation between pupil dilation and stimulus contrast was obtained, showing larger pupil dilation (or higher contrast stimuli) correlating with faster saccade latencies, larger amplitude, higher peak velocities, and smaller endpoint deviation. Together, our results demonstrated the influence of absolute pupil size induced by global luminance level and baseline-corrected pupil dilation associated with motor preparation on saccade latency and metrics, implicating the role of the SC in this behavior.
扫视是一种快速的眼球运动，用于以串行方式移动高清晰度的中央凹，从而对视觉场景进行探索。已知刺激对比度可以通过改变中脑结构上丘中的视觉活动来调节扫视潜伏期和度量，而上丘是与扫视生成因果相关的结构。然而，视觉信号的质量也应该通过投射到视网膜上的光量来调节，而这是由瞳孔的大小来控制的。尽管绝对瞳孔大小应该调节视觉信号，并反过来影响扫视反应，但研究这种关系的研究非常有限。此外，瞳孔大小与运动准备有关。然而，瞳孔扩张在扫视度量中的作用仍未得到探索。通过在扫视任务中改变周围背景亮度水平和目标视觉对比度，我们研究了绝对瞳孔大小和基线校正的瞳孔扩张在扫视潜伏期和度量中的作用。在背景亮度水平较低的情况下，目标检测的准确率更高，而较大的绝对瞳孔直径与较小的扫视幅度和较高的扫视峰值速度相关。更有趣的是，我们获得了瞳孔扩张和刺激对比度之间可比较的调制关系，表明更大的瞳孔扩张（或更高对比度的刺激）与更快的扫视潜伏期、更大的幅度、更高的峰值速度以及更小的终点偏差相关。总的来说，我们的结果表明，由整体亮度水平引起的绝对瞳孔大小以及与运动准备相关的基线校正瞳孔扩张对扫视潜伏期和度量有影响，这暗示了上丘在这种行为中的作用。
