The impact of visual experience on the development of the motion pathway in the ferret

对复杂运动模式的感知受到损害，这需要整合多个运动元素 在一系列发育障碍中。在大脑中，复杂运动信号的处理是由一个 包括初级视觉皮质(V1)和高级运动区的专用视觉通路。很少有 了解决定其发展的机制，就像大多数更高级别的视觉一样 功能。在这里，我们将测试一个可能在其发展中发挥主要作用的因素，视觉体验。我们会 研究运动路径何时需要视觉体验，以及哪种视觉 经验是必需的。我们将在雪貂身上进行这些实验，雪貂已经成为一种主要动物 视觉发育模型，因为它在出生时就相对不成熟。雪貂的运动路径包括 V1区和PSS区，一个较高阶视觉区。我们将调查视觉体验对此的影响 途径在2组实验中。在第一组实验中，我们将调查在哪个时间段内 运动通路的正常发展需要经验。为此，我们也将饲养动物 正常情况下，或在特定时间段内保留视觉体验。然后我们将调查视觉缺失是如何 经验通过测量V1和PSS中的方向选择性和信号来影响通路的功能 V1和PSS中的运动集成。这些实验将使用PSS中的细胞外记录来执行， 双光子成像结合V1逆行示踪剂选择性研究PSS- 投射V1神经元。我们还将在成年动物身上进行行为实验，以调查 这对运动知觉有持久的影响。我们预计将发现两个关键时期，在这两个时期内，愿景 需要，一个发展方向选择性的初始阶段，一个运动整合的后期。 这将证明视觉体验对正在发展的视觉系统具有持续的影响。在一个 第二组实验，我们将测试运动路径需要什么样的视觉体验 通过测试不同类型的视觉体验对未成熟运动路径的影响来发展。 更准确地说，我们将确定包含多个运动元素的复杂运动刺激是否简单 只包含一个移动元素的移动刺激或静态刺激可以增强未成熟方向的选择性 和运动集成。我们期望发现，只有简单的运动，而不是静态的刺激，才能增强方向 选择性。我们也希望找到复杂的运动，但其他刺激都不能增强运动 整合。这些发现将证明不同的视觉功能需要不同种类的视觉 为他们的发展提供经验。总而言之，我们的实验将是对如何 视觉体验影响着一条重要的高等视觉通路的发展。他们会做出贡献 对塑造高级视觉皮质发育机制的重要见解，并可能有助于识别 在一系列发育障碍中观察到的运动处理缺陷的原因。

The perception of complex motion patterns, which requires integration of multiple moving elements, is impaired in a range of developmental disorders. In the brain, processing of complex motion signals is handled by a dedicated visual pathway that includes primary visual cortex (V1) and a higher order motion area. Very little is known about the mechanisms that determine its development, as is the case for most higher level visual functions. Here, we will test one factor likely to play a major role in its development, visual experience. We will investigate when visual experience is required for the motion pathway to develop, and what kind of visual experience is required. We will perform these experiments in the ferret, which has become a major animal model for visual development because of its relative immaturity at birth. The ferret’s motion pathway includes V1 and area PSS, a higher order visual area. We will investigate the influence of visual experience on this pathway in 2 sets of experiments. In the first set of experiments, we will investigate during which time visual experience is required for the motion pathway to develop normally. To this end, we will raise animals either normally, or withhold visual experience for certain time periods. We will then investigate how lack of visual experience impacts the pathway’s function by measuring direction selectivity in V1 and PSS, and signatures of motion integration in V1 and PSS. These experiments will be performed using extracellular recordings in PSS, and two-photon imaging combined with retrograde tracers in V1 to selectively study the responses of PSS- projecting V1 neurons. We will also perform behavioral experiments in adult animals to investigate whether there are lasting consequences on motion perception. We expect to find 2 critical periods during which vision is required, an initial period for the development of direction selectivity, and a later period for motion integration. This would demonstrate that visual experience has a sustained impact on the developing visual system. In a second set of experiments, we will test which kinds of visual experience are required for motion pathway development by testing the impact of different kinds of visual experience on the immature motion pathway. More precisely, we will determine whether complex motion stimuli containing multiple moving elements, simple moving stimuli containing only one moving element, or static stimuli can enhance immature direction selectivity and motion integration. We expect to find that only simple motion, but not static stimuli, can enhance direction selectivity. We also expect to find that complex motion, but none of the other stimuli can enhance motion integration. These findings would demonstrate that different visual functions require different kinds of visual experience for their development. In summary, our experiments would be a systematic investigation of how visual experience impacts the development of an important higher vision pathway. They would contribute important insights into the mechanisms shaping the development of higher visual cortex, and may help identify reasons for the deficits in motion processing observed in a range of developmental disorders.