Integration of visual information and behavioral modulation in the superior colliculus

项目总结 沿着视觉路径并行地提取不同的视觉特征，并在不同的 级别。早期可以发现两条平行的通路，视网膜的投射指向背侧 以皮质区域为靶点的膝状核和投射到枕骨的上丘 在其他结构中。除了接受来自视网膜的直接输入外，SC还从 初级视皮层(V1)。这两条途径通常被称为主要途径和次要途径 它们是相互关联的，特别是在SC一级。重要的是，视网膜和皮质的输入 SC融合成一种形态和分子定义的细胞类型：广域垂直细胞(WFV)。 WFV细胞树突状分支在很大一部分视野中采样，并跨越整个脑组织深度 可视层次，这表明它们将本地和远程输入结合在一起。它们的形态和 到枕骨的投影在不同物种之间是保守的。这些观察结果使WFV细胞成为关键的积分器 不同路径上的视觉信息。 为了了解WFV细胞如何整合视觉信息，研究人员将进行仔细的 它们在两种动物中的输入、反应特性及其受内部因素和V1的调节 模型：小鼠(Mus Musculus)和树鼠(Tupaia Belangerii)，一种高度可视化和 靠近灵长类动物。首先，WFV细胞的反应特性和运动效应将被表征在 用钙成像唤醒小鼠。将通过使用逆行病毒跟踪来识别WFV细胞输入，并进一步 通过组织学方法进行鉴定。其次，皮质输入将通过使用化学发生学在功能上进行隔离 确定这些输入如何塑造WFV细胞的视觉反应的方法。最后，在老鼠身上的这些发现将 可作为参考，因为这项工作已扩展到树鼠。在不同动物模型中进行的其他研究 已显示在SC和贡献中可以找到的特征选择性的量的可变性 对SC中的视觉反应的主要视觉通路。为了协调这些结果，一项比较研究将 在有许多遗传工具可用的小鼠和表现出高度视觉的树鼠身上进行了研究 敏锐和视觉驱动的行为。该项目将产生令人信服的结果，关于视觉的集成 整个视觉系统的信息，允许在两个物种中直接比较相同定义的细胞类型， 并揭示内部状态如何潜在地塑造SC中的视觉反应。

PROJECT SUMMARY Distinct visual features are extracted in parallel along the visual pathways and combined at different levels. Two parallel pathways can be found early on, with projections from the retina targeting the dorsal lateral geniculate nucleus, which targets cortical areas, and the superior colliculus (SC), which projects to the pulvinar among other structures. In addition to receiving direct input from the retina, the SC also receives inputs from the primary visual cortex (V1). These two pathways are often referred to as the primary and the secondary pathway respectively and are inter-connected, notably at the level of the SC. Importantly, retinal and cortical inputs in the SC converge onto one morphologically and molecularly defined cell type: the wide-field vertical cells (WFV). WFV cells dendritic arborizations sample a large part of the visual field and span across the entire depth of the visual layers of the SC, suggesting that they integrate both local and long-range inputs. Their morphology and projection to the pulvinar are conserved across species. These observations place WFV cells as key integrators of visual information across pathways. To understand how WFV cells integrate visual information, the investigator will perform a careful characterization of their inputs, response properties and modulation by internal factors and V1 in two animal models: mice (Mus musculus) and tree shrews (Tupaia belangerii), an animal model which is highly visual and close to primates. First, WFV cells responses properties and the effect of locomotion will be characterized in awake mice using calcium imaging. WFV cells inputs will be identified by using retrograde viral tracing and further identified by histological methods. Secondly, cortical inputs will be isolated functionally by using a chemogenetic approach to determine how these inputs shape WFV cells visual responses. Finally, these findings in mice will be used as a reference as this work is expanded to tree shrews. Other studies carried in different animal models have shown a variability in the amount of feature selectivity that can be found in the SC and in the contribution of the primary visual pathway to visual responses in the SC. To reconcile these results, a comparative study will be conducted in both mice, where many genetic tools are available, and tree shrews, which display high visual acuity and visually-driven behavior. This project will yield compelling results regarding the integration of visual information across the visual system, allow a direct comparison of the same defined cell-type across two species, and reveal how internal states potentially shape visual responses in the SC.