Cortical circuit mechanisms of visual shape processing

项目摘要 人类和其他灵长类动物依赖于使用视觉形状信息来识别物体并与之互动。 世界这个项目的目标是获得灵长类动物大脑皮层如何处理的机械见解 视觉形状信息。皮质区V4是这些机制研究的理想场所，因为许多V4 神经元对视觉形状进行调整，显示出对物体沿着的凸起或凹陷部分的偏好。 边界轮廓这种对视觉形状的调整被认为是行为相关对象的基础 虽然我们知道它的原理，但我们对其机械实现知之甚少。小奇，我们不知道 通路和细胞类型负责在V4神经元中产生这种调谐。在这个项目中，我们将开始 通过在猴子中采用病毒载体介导的细胞类型特异性光遗传学来填补这些知识空白。在 目标1，我们将问：V4中的视觉形状处理如何依赖于来自 早期皮层V1和V2区？与这一目标相关的实验将检验前馈 来自V2区的兴奋是支配V4神经元的形状调谐的主导因素。在目标2中，我们将 问：V4的视觉形状加工如何依赖于该区域内的局部抑制信号？的 与这一目标相关的实验将检验抑制性神经元对形状进行调整的假设， 局部抑制使兴奋性神经元的调谐变得尖锐。实现这些目标将首先提供关键的 深入了解前馈激励和局部抑制在视觉形状处理中的作用。更深 了解灵长类动物的这些皮层回路机制有可能改变 我们治疗形式视觉障碍，如视觉失认症。神经回路的光遗传学研究进展 对猴子的解剖也将有助于研究其他复杂的大脑功能，这些功能是特定于 灵长类：推进基础科学和人类医学的必要条件。

PROJECT SUMMARY Humans and other primates rely on using visual shape information to identify and interact with objects in the world. The goal of this project is to gain mechanistic insights into how the primate cerebral cortex processes visual shape information. Cortical area V4 is an ideal locus for these mechanistic studies because many V4 neurons are tuned for visual shape, showing preferences for convex or concave segments along an object's bounding contour. This tuning for visual shape is presumed to be a foundation for behaviorally relevant object representations, but we know little about its mechanistic implementation. Chiefly, we do not know which cortical pathways and cell types are responsible for generating this tuning in V4 neurons. In this project, we will begin to fill these knowledge gaps by employing viral vector-mediated, cell type-specific optogenetics in monkeys. In Aim 1, we will ask: How does visual shape processing in V4 depend on feedforward excitatory signals from earlier cortical areas V1 and V2? The experiments related to this aim will test the hypothesis that feedforward excitation from area V2 is the dominant factor in dictating the shape tuning of V4 neurons. In Aim 2, we will ask: How does visual shape processing in V4 depend on local inhibitory signals within this area? The experiments related to this aim will test the hypothesis that inhibitory neurons are tuned for shape, and that local inhibition sharpens the tuning of excitatory neurons. Accomplishing these aims will provide critical first insights into the role of feedforward excitation and local inhibition in visual shape processing. A deeper understanding of these cortical circuit mechanisms in primates has the potential to transform the way in which we treat disorders of form vision such as visual agnosia. Advancing optogenetic techniques for neural circuit dissection in monkeys will also facilitate the investigation of other complex brain functions that are specific to primates: an imperative for advancing basic science and human medicine.