Corrigan Benjamin W, Gulli Roberto A, Doucet Guillaume, Martinez-Trujillo Julio C
Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada.
Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada.
J Vis. 2017 Oct 1;17(12):15. doi: 10.1167/17.12.15.
Virtual environments (VE) allow testing complex behaviors in naturalistic settings by combining highly controlled visual stimuli with spatial navigation and other cognitive tasks. They also allow for the recording of eye movements using high-precision eye tracking techniques, which is important in electrophysiological studies examining the response properties of neurons in visual areas of nonhuman primates. However, during virtual navigation, the pattern of retinal stimulation can be highly dynamic which may influence eye movements. Here we examine whether and how eye movement patterns change as a function of dynamic visual stimulation during virtual navigation tasks, relative to standard oculomotor tasks. We trained two rhesus macaques to use a joystick to navigate in a VE to complete two tasks. To contrast VE behavior with classic measurements, the monkeys also performed a simple Cued Saccade task. We used a robust algorithm for rapid classification of saccades, fixations, and smooth pursuits. We then analyzed the kinematics of saccades during all tasks, and specifically during different phases of the VE tasks. We found that fixation to smooth pursuit ratios were smaller in VE tasks (4:5) compared to the Cued Saccade task (7:1), reflecting a more intensive use of smooth pursuit to foveate targets in VE than in a standard visually guided saccade task or during spontaneous fixations. Saccades made to rewarded targets (exploitation) tended to have increased peak velocities compared to saccades made to unrewarded objects (exploration). VE exploitation saccades were 6% slower than saccades to discrete targets in the Cued Saccade task. Virtual environments represent a technological advance in experimental design for nonhuman primates. Here we provide a framework to study the ways that eye movements change between and within static and dynamic displays.
虚拟环境（VE）通过将高度可控的视觉刺激与空间导航及其他认知任务相结合，允许在自然主义环境中测试复杂行为。它们还允许使用高精度眼动追踪技术记录眼动，这在检查非人灵长类动物视觉区域神经元反应特性的电生理研究中很重要。然而，在虚拟导航期间，视网膜刺激模式可能高度动态，这可能会影响眼动。在这里，我们研究相对于标准动眼神经任务，在虚拟导航任务期间眼动模式是否以及如何随动态视觉刺激而变化。我们训练了两只恒河猴使用操纵杆在虚拟环境中导航以完成两项任务。为了将虚拟环境行为与经典测量进行对比，猴子们还执行了一个简单的线索性扫视任务。我们使用了一种强大的算法来快速分类扫视、注视和平稳跟踪。然后我们分析了所有任务期间，特别是虚拟环境任务不同阶段的扫视运动学。我们发现，与线索性扫视任务（7:1）相比，虚拟环境任务中的注视与平稳跟踪比率更小（4:5），这反映出在虚拟环境中比在标准视觉引导扫视任务或自发注视期间，更密集地使用平稳跟踪来使目标成像于中央凹。与针对未奖励物体的扫视（探索）相比，针对奖励目标的扫视（利用）往往具有更高的峰值速度。虚拟环境中的利用性扫视比线索性扫视任务中针对离散目标的扫视慢6%。虚拟环境代表了非人灵长类动物实验设计中的一项技术进步。在这里，我们提供了一个框架来研究眼动在静态和动态显示之间以及内部如何变化。
