Superior Colliculus Interactions with the Parabigeminal Nucleus

项目总结/摘要 最近的研究表明，上级丘（SC）和二叠旁核（PBG）是重要的 参与视觉诱发的防御行为的选择和激活的结构，如冻结和 逃跑然而，SC和PBG在视觉诱发行为的起始中所起的确切作用是 未知的，部分原因是由于在连接SC和PBG的突触回路的知识中存在差距，以及连接SC和PBG的方式。 PBG接收视觉信号。拟议项目将通过完成一项详细的 检查连接SC和PBG的电路。目标1实验将定义形态和层状 含有谷氨酸脱羧酶（GAD）或小清蛋白（PV）并发送投射的SC细胞的分布 到PBG。Aim 2实验将测试这两种细胞类型是否直接或间接地接受来自 视网膜和/或初级视觉皮层。目的3：研究SC-PBG连接的突触特性。 为了研究这些回路，所提出的实验使用了病毒载体注射的新组合， 转基因小鼠，免疫组织化学，来自鉴定的细胞类型的体外全细胞记录，以及光遗传学 细胞类型特异性突触末端的激活。这种方法的组合将解决根本问题 关于SC和PBG的循环问题，同时为申请人提供广泛的培训， 神经科学

PROJECT SUMMARY/ABSTRACT Recent studies have implicated the superior colliculus (SC) and parabigeminal nucleus (PBG) as important structures involved in the selection and activation of visually-evoked defensive behaviors, such as freeze and escape. However, the precise role that the SC and PBG play in the initiation of visually-evoked behavior is unknown, in part due to a gap in knowledge of the synaptic circuits that link the SC and PBG, and the manner in which the PBG receives visual signals. The proposed project will address this gap by completing a detailed examination of circuits that link the SC to the PBG. Aim 1 experiments will define the morphology and laminar distribution of SC cells that contain glutamic acid decarboxylase (GAD) or parvalbumin (PV) and send projections to the PBG. Aim 2 experiments will test whether these two cells types receive direct or indirect input from the retina and/or primary visual cortex. Aim 3 experiments will define the synaptic properties of SC-PBG connections. To investigate these circuits, the proposed experiments use novel combinations of viral vector injections in transgenic mice, immunohistochemistry, in vitro whole cell recordings from identified cell types, and optogenetic activation of cell-type specific synaptic terminals. This combination of approaches will address fundamental questions regarding the circuity of the SC and PBG while providing the applicant with broad-based training in neuroscience.