Spatiotemporal representation in ventral visual pathway

腹侧视觉通路的时空表征

• 批准号: 10331833
• 负责人: Anitha Pasupathy
• 金额: $ 44.4万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-02-01 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10331833
• 关键词: Aging; Alzheimer' s Disease; Animals; Appearance; Area; Articular Range of Motion; Behavior; Biological; Characteristics; Complex; Cues; Custom; Data; Dorsal; Environment; Foundations; Impairment; Individual; Investigation; Macaca; Methods; Modeling; Monkeys; Motion; Motion Perception; Neurons; Pathway interactions; Perception; Play; Population; Primates; Process; Psychophysics; Reaction Time; Role; Rotation; Shapes; Signal Transduction; Source; Speed; Stimulus; Stream; Testing; Time; Translating; Translations; V4 neuron; Vision; Visual; Visual Cortex; Visual Fields; Visual Motion; Visual Pathways; Visual system structure; area MT; area V4; awake; base; behavioral study; density; design; experimental study; inferotemporal cortex; insight; neurophysiology; novel; object motion; object shape; receptive field; response; retinal imaging; spatiotemporal; temporal measurement; visual information; visual processing; visual stimulus

In natural vision, objects change appearance over time as they translate, rotate, become occluded or undergo complex transformations, e.g., during biological motion. In these dynamic environments, the visual cortex integrates information over multiple spatial and temporal scales to compute motion trajectories and represent the shape of objects. To understand how form and motion percepts are derived from such dynamic visual input, we will investigate how neuronal responses in area V4—an intermediate stage along the ventral visual pathway—are shaped by the spatiotemporal integration of time-varying visual stimuli. We will test the hypothesis that the spatiotemporal characteristics of V4 neurons are suited for tracking dynamic objects: specifically, V4 motion signals arise from object-tracking over longer spatiotemporal windows than comparable dorsal-stream areas and that V4 signals reflect form transformations at an object level rather than at the level of the local retinal image. We will leverage the percept of long-range apparent motion to probe the role of V4 neurons in motion perception (Aim 1). When a stimulus intermittently skips across the visual field with large spatial and temporal steps, it induces a strong illusory motion percept but neurons in V1 and MT of the dorsal visual stream are strikingly insensitive to the direction of the perceived motion. Psychophysical studies have argued that long-range apparent motion relies not on the dorsal stream but on higher order object tracking processes with large spatiotemporal windows in the ventral visual stream. We will conduct the first neurophysiological investigations in the awake monkey to ascertain the role of V4 in the perception of long- range apparent motion. Next (Aim 2), we will use dynamic stimuli that rotate in the fronto-parallel plane, and translate and rotate in depth, to determine whether V4 neurons encode other common dynamic object transformations (beyond long-range translation), and whether the encoding is based on a sequence of static poses, as in the inferotemporal (IT) cortex, or dynamic transformations. Finally, we will examine the encoding and perception of partially occluded dynamic objects (Aim 3). When an occluded object moves, different parts of the object are revealed over time and integration across time and multiple neuronal receptive fields is required to build an entire object representation. As animals discriminate moving occluded objects, we will study 50-100 neurons with high-density Neuropixels probes. We will use single trial population decoding methods to determine how dynamic stimulus information is integrated across the V4 network to extract object shape and the motion trajectory and how V4 contributes to psychophysical behavior. We anticipate that our results will reveal an important role for V4 in the processing of dynamic stimuli that is complementary to those of MT and IT cortex and will establish the level of internal visual representation operating in V4. Our studies will provide a deeper understanding of the neuronal basis of global motion perception and the tracking of dynamic objects—processes that are impaired in aging populations, especially those with Alzheimer’s disease.

在自然视觉中，物体随着时间的流逝而随着时间的流逝而改变，旋转，被遮挡或经历 复杂的转化，例如在生物运动过程中。在这些动态环境中，视觉皮层 在多个空间和临时尺度上集成了信息，以计算运动轨迹并表示 物体的形状。了解如何从这种动态视觉范围内得出形式和运动知觉 输入，我们将研究如何在v4区域中的神经元反应 - 沿腹侧视觉的中间阶段 途径 - 随时间变化的视觉刺激的时空整合形成。我们将测试 假设V4神经元的时空特征适合跟踪动态对象： V4运动信号是由对对象跟踪在更长的时空窗户上的对象跟踪而不是可比的 背流区域和V4信号反映了对象级别的形式转换，而不是在级别上 局部视网膜图像。我们将利用对远程明显运动的感知来探测V4的作用 运动感知中的神经元（目标1）。当刺激间歇性地跳过视野时 空间和临时步骤，它引起了强烈的虚幻运动感知，但在背侧的V1和MT中神经元 视觉流对感知运动的方向非常不敏感。心理物理研究有 认为远距离明显运动不是依赖背面流，而是基于高阶对象跟踪 在腹侧视觉流中带有大空间临时窗口的过程。我们将进行第一个 清醒猴子中的神经生理研究，以确定V4在长期感知中的作用 范围明显运动。接下来（AIM 2），我们将使用在额 - 平行平面旋转的动态刺激，然后 深入翻译和旋转，以确定V4神经元是否编码其他常见的动态对象 转换（超出远程翻译），以及编码是否基于一系列静态 姿势，如颞下降（IT）皮层或动态转换。最后，我们将检查编码 以及对部分阻塞动态对象的感知（AIM 3）。当咬合的物体移动时，不同的部分 随着时间的流逝而揭示该物体的揭示，并且跨时间和多个神经元接受场是 需要建立整个对象表示。当动物区分移动的封闭物体时，我们将 研究具有高密度神经质子问题的50-100个神经元。我们将使用单个试用人群解码 确定如何在V4网络上集成动态刺激信息以提取对象的方法 形状和运动轨迹以及V4如何促进心理物理行为。我们预计我们的 结果将揭示V4在处理动态刺激的处理中的重要作用 MT和IT皮层的构造，并将建立V4中运行的内部视觉表示的水平。我们的研究将 对全球运动感知的神经元基础有更深入的了解和动态的跟踪 物体 - 衰老人群中受损的过程，尤其是那些患有阿尔茨海默氏病的物体。