The energy-based and feature tracking motion systems and their interactions

不可否认，运动感知对于许多日常活动都是至关重要的，比如在拥挤的环境中行走、练习运动、过马路和开车。然而，运动感知是复杂的。现在已经确定，视觉系统依赖于两种根本不同的策略来处理运动，但这两种运动系统的相对贡献仍然难以捉摸。目前的研究计划将研究运动感知的潜在过程，以阐明这两个运动系统是如何相互作用的。这项研究的中心方法在于开发新的心理物理范式(即无创功能测试)来调查影响运动对比敏感度的潜在因素。事实上，运动感知依赖于许多处理水平，从光感受器对光的吸收到大脑皮层的神经处理，而这条路径上的许多因素可以影响感知运动的能力。这些新的心理物理范式将有助于准确描述运动过程，也可以用于定位运动知觉下降的根本原因。我们感知运动的能力随着年龄的增长而变化。这些心理物理工具将被用来阐明哪个加工阶段是与年龄相关的运动知觉下降的原因。目前的研究计划将建立在我们最近开发的强大的噪声范例的基础上，能够评估视觉系统的各种属性的影响。这一范式是为低水平运动系统开发的。然而，运动感知也依赖于特征跟踪运动系统，这是一个需要注意资源的高级运动系统。第一个研究轴将采用我们的噪声范式来表征运动处理，以特征跟踪运动系统来评估影响运动感知的潜在因素。通过评估年轻人和老年人(轴2)，我们将能够确定哪些潜在因素导致与年龄相关的特征跟踪能力下降。第三个研究轴将调查这两个运动系统作为偏心率(即周边视觉)、运动速度和亮度的函数的相对贡献。最后一个研究轴将使用第三个轴的结果来研究健康老龄化对两个运动系统的相对贡献的影响。总而言之，这项研究计划将提供关于视觉系统如何处理运动的基础知识，并将量化老化对两个运动系统的处理及其相互作用的影响。

Motion perception is undeniably crucial for many daily activities such as walking in a crowded environment, practicing a sport, crossing a street and driving. However, motion perception is complex. It is now well established that the visual system relies on two fundamentally different strategies to process motion, but the relative contribution of these two motion systems is still elusive. The current research program will investigate the underlying processes of motion perception to elucidate how the two motion systems interact. The central approach of this research program consists in developing novel psychophysical paradigms (i.e., non-invasive functional tests) to investigate the underlying factors affecting motion contrast sensitivity. Indeed, motion perception depends on many processing levels from the absorption of light by photoreceptors to neural processing in the cortex, and many factors along this path can affect the ability to perceive motion. These new psychophysical paradigms will be useful to precisely characterize the motion processes, and can also be useful to localize the underlying cause of a motion perception decline. Our ability to perceive motion changes with age. These psychophysical tools will be used to elucidate which processing stage is responsible for an age-related decline in motion perception. The current research program will build on our recent development of a powerful noise paradigm enabling to evaluate the impact of various properties of the visual system. This paradigm was developed for the low-level motion system. However, motion perception also relies on the feature tracking motion system, which is a high-level motion system that requires attentional resources. The first research axis will adapt our noise paradigm to characterize motion processing to the feature tracking motion system to evaluate the underlying factors affecting motion perception. By evaluating young and older adults (axis 2), we will be able to identify which underlying factors are responsible for age-related decline in feature tracking. The third research axis will investigate the relative contribution of the two motion systems as a function of eccentricity (i.e., peripheral vision), motion speed and luminance intensity. The last research axis will use the outcome of the third axis ton investigate the impact of healthy aging on the relative contributions of the two motion systems. In sum, this research program will provide fundamental knowledge about how the visual system processes motion and will quantify the effect of aging on the processing by the two motion systems and their interactions.