Linking Neural Population Activity and Visual Perception

描述（由申请人提供）：感觉神经科学的中心目标是理解感觉皮层区域中的神经代码，通过监测参与感知任务的受试者的神经反应，人们可以在真实的时间内“阅读”神经表征的内容并解释受试者的感知能力。这项研究的首要目标是了解灵长类动物V1神经代码的性质。具体来说，我们将集中在两个重要的知觉任务，模式识别和轮廓分组的神经代码。在目标1中，我们将测试假设，此外， V1表示依赖于视网膜定位图上神经群体反应的大规模空间变化模式，而不是由高度选择性神经元的一小部分的活动来表示刺激。具体来说，我们最近发现了一种新的地形信号在V1，反映了空间表示的刺激的亮度调制（LM）在V1的视网膜地形图。我们还记录了一个类似的视网膜信号，反映了全球模式的刺激的对比度调制（CM）。通过监测猴子执行阈值方向辨别任务时视网膜和柱状尺度的神经反应，我们将检验视网膜LM和CM信号有助于视觉感知的假设。在目标2中，我们将考察灵长类动物V1对知觉分组的贡献--将属于同一物体的不同视觉元素分组在一起的过程。具体来说，我们将测试的假设，涉及配置特定的横向相互作用在V1的机制在这个过程中发挥了关键作用，并启动分组连接在一起的元素对可能属于同一个对象。为了验证这一假设，我们将监测猴子在V1中的神经群体反应，因为它们执行具有挑战性和自然主义的感知分组任务。此外，这些实验将被用来确定的规则，通过这些规则，当地的图像元素联合收割机的反应，以形成一个时空模式的人口活动在灵长类动物V1。总的来说，拟议的实验可能提供重要的和独特的见解，介导皮层感觉处理的神经机制。

DESCRIPTION (provided by applicant): A central goal of sensory neuroscience is to understand the neural code in sensory cortical areas to the point where, by monitoring neural responses in a subject engaged in a perceptual task, one could "read", in real time, the content of the neural representation and account for the subject's perceptual capabilities. The overarching goal of the proposed research is to understand the nature of the neural code in primate V1. Specifically, we will focus on the neural code in two important perceptual tasks, pattern discrimination and contour grouping. In Aim 1 we will test the hypothesis that, in addition to representing stimuli by the activity of a small subset of highly selective neurons, V1 representation relies on the large-scale pattern of spatial variations in neural population responses across the retinotopic map. Specifically, we recently discovered a novel topographic signal in V1, reflecting the spatial representation of the stimulus's luminance modulations (LM) in V1's retinotopic map. We also documented a similar retinotopic signal reflecting the global pattern of the stimulus' contrast modulations (CM). By monitoring neural responses at the retinotopic and columnar scales as monkeys perform a threshold orientation discrimination task, we will test the hypothesis that the retinotopic LM and CM signals contribute to visual perception. In Aim 2 we will examine the contribution of primate V1 to perceptual grouping - the process of grouping together disparate visual elements that belong to the same object. Specifically, we will test the hypothesis that mechanisms involving configuration-specific lateral interactions in V1 play a key role in this process, and initiate the grouping by linking together pairs of elements that are likely to belong to the same object. To test this hypothesis, we will monitor neural population responses in V1 of monkeys as they perform a challenging and naturalistic perceptual grouping task. In addition, these experiments will be used to determine the rules by which responses to local image elements combine to form a spatiotemporal pattern of population activity in primate V1. Overall, the proposed experiments are likely to provide important and unique insights into the neural mechanisms that mediate cortical sensory processing.