Integration of visual information and behavioral modulation in the superior colliculus

项目摘要 不同的视觉特征被并行地沿着视觉路径提取，并在不同的位置组合。 程度.早期可以发现两条平行的通路，视网膜的投射指向背侧 膝状体核，其靶向皮质区域，和上级丘（SC），其投射到枕 以及其他结构。除了从视网膜接收直接输入外，SC还从视网膜接收输入。 初级视皮层（V1）。这两个途径通常被称为主要途径和次要途径 重要的是，视网膜和皮层的输入，在SC的水平， SC集中在一个形态和分子定义的细胞类型：宽视野垂直细胞（WFV）。 WFV细胞树突状分支对视野的大部分进行采样，并跨越视野的整个深度。 SC的视觉层，这表明他们整合了本地和远程输入。其形态和 向枕的投射在物种间是保守的。这些观察结果将WFV细胞作为关键集成商 视觉信息的传递。 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 在两种动物中表征它们的输入、反应特性以及内部因素和V1对它们的调制 模型：小鼠（Mus musculus）和树鼩（Tupaia belangerii），一种高度可视化的动物模型， 接近灵长类。首先，WFV细胞的反应特性和运动的影响将在 使用钙成像唤醒小鼠。WFV细胞输入将通过使用逆行病毒追踪来鉴定，并进一步 通过组织学方法鉴定。其次，皮层输入将被隔离功能，通过使用化学遗传学 方法来确定这些输入如何塑造WFV细胞的视觉反应。最后，这些在老鼠身上的发现将 作为参考，因为这项工作是扩大到树鼩。在不同动物模型中进行的其他研究 已经显示出在SC和贡献中可以发现的特征选择性的量的可变性 SC中视觉反应的主要视觉通路。为了协调这些结果，将进行一项比较研究 在小鼠和树鼩中进行，小鼠中有许多遗传工具，树鼩表现出高视觉 敏锐度和视觉驱动的行为。该项目将产生令人信服的结果，关于整合视觉 跨视觉系统的信息，允许直接比较两个物种之间相同的定义的细胞类型， 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.