Parallel pathways in visual cortex: functional connectivity of output pathways fr

描述（由申请人提供）：理解皮层神经回路的组织原理对于理解其计算功能是必要的。这一原理为新领域的“连接组学”提供了信息，该领域致力于生成不同尺度的大脑或其子部分的线路图。在灵长类动物的视觉皮层中，V1和V2区将从视网膜接收到的信息分配到几乎所有的高级区域，将这些信息分别分类到空间视觉和物体视觉的背侧和腹侧处理流中。本应用程序的目的是揭示V1和V2的解剖和功能连接规则 输出通路，以便了解这些区域如何将视网膜信号细化和重组为视觉处理流，以及这些通路如何有助于创建更高区域神经元的复杂感受野（RF）特性。从V1到V2的平行途径投射到不同的细胞色素氧化酶条纹（厚，薄和苍白）。在上一次赠款期间， 在V1和V2之间发现了4条分离的通路。我们还发现了V1通路的专门功能组织，这些组织与厚条纹和淡条纹相关，可能是V2 RF对有角度和弯曲轮廓的反应的基础。本建议以这些调查结果为基础。目的1的目标是通过确定单个V1输出细胞在V1和V2方向图上的轴突和树突布局，了解单个V1细胞如何有助于产生V2 RF。我们将首次在介观尺度上提供V1细胞投射到特定V2条纹的全面解剖学描述，包括V1内和V2内 确定的细胞类型的轴突分支，以及它们在V1和V2内的功能组织。这些信息将提供对前馈与V2内机制在V2 RF生成中的作用以及V1内和V1至V2回路对轮廓处理的贡献的见解。然后，我们将调查是否解剖和功能隔离的4个途径是维持或失去下游的V2。Aim2的目标是确定两个V2浅色条纹类型的面积投影，我们最近已经证明这是不同的隔间。这项研究将确定每个苍白条纹的贡献，背侧和腹侧处理流。V2和V4包含视觉刺激方向和颜色的分离表示。Aim3的目标是确定V2和V4之间的连接是否发生在相似特征表示的区域之间，或者V4中是否发生跨流收敛。本研究还将提供前馈与区域内机制在V4 RF和特征图生成中的作用的见解。这项研究具有重要意义，因为它将揭示V1和V2输出的解剖和功能布线原理 这些通路将作为其功能的假设驱动和解剖学约束研究的基础。这项研究具有创新性，因为它将功能成像与单轴突的高分辨率标记相结合，使用新的单轴突标记和重建方法。

DESCRIPTION (provided by applicant): Understanding organizing principles for neural circuits in the cortex is necessary to understand their computational function. This principle has informed the new field of "connectomics", devoted to generating wiring diagrams of the brain, or subsections of it, at different scales. In the primate visual cortex, areas V1 and V2 distribute information they receive from the retina to virtually all higher areas, sorting this information ino dorsal and ventral processing streams for spatial and object vision, respectively. The objective of this application is to uncover the rules of anatomical and functional connectivity for V1 and V2 output pathways, in order to understand how these areas may refine and re-organize retinal signals into visual processing streams, and how these pathways contribute to creating the complex receptive field (RF) properties of neurons in higher areas. Parallel pathways from V1 to V2 project to distinct cytochrome-oxidase stripes (thick, thin and pale). During the previous grant period, we discovered 4 segregated pathways between V1 & V2. We also discovered specialized functional organizations of V1 pathways related to thick and pale stripes that may underlie the responses of V2 RFs to angled and curved contours. This proposal builds upon these findings. The goal of Aim 1 is to understand how single V1 cells contribute to generating V2 RFs, by determining the axonal and dendritic layout of single V1 output cells over the V1 and V2 orientation maps. We will provide the fist comprehensive anatomical description at mesoscopic scale of V1 cells projecting to specific V2 stripes, including the intra-V1 and intra-V2 axonal arborizations of identified cell types, and their functional organization within both V1 & V2. This information will provide insights into the roles of feedforward vs. intra-V2 mechanisms in the generation of V2 RFs, and on the contribution of intra-V1 and V1-to-V2 circuits to the processing of contours. We will then investigate whether anatomical and functional segregation of the 4 pathways is maintained or lost downstream of V2. The goal of Aim2 is to determine the areal projections of the two V2 pale stripe types, which we have recently demonstrated to be distinct compartments. This study will determine each pale stripe contribution to the dorsal and ventral processing streams. V2 and V4 contain segregated representations for visual stimulus orientation and color. The goal of Aim3 is to determine whether connections between V2 & V4 occur between regions of similar featural representation, or whether cross-stream convergence occurs in V4. This study will also provide insights into the roles of feedforward vs. intra-areal mechanisms in the generation of V4 RFs and featural maps. The proposed research is significant because it will reveal anatomical and functional wiring principles for V1 and V2 output pathways that will serve as a foundation for hypothesis-driven and anatomically-constrained studies of their function. The proposed research is innovative because it combines functional imaging with high-resolution labeling of single axons, using novel methods for single axon labeling and reconstruction.