Taste neuron connectivity and branching revealed by sparse cell genetic labeling

 描述（由申请人提供）：感觉组织的一般特征是神经元可根据分子、形态和功能特征分为不同类型。这种类型的组织是否存在于味觉系统中尚不清楚。一般认为味觉感受器细胞以不同类型存在。下一个关键步骤是 确定这些不同类型的味觉感受器细胞如何与将味觉信息传递到大脑的神经节神经元连接。由于外周味觉神经轴突成束侵入舌头，每个层次的单个轴突都相互缠绕，过去重建单个纤维的尝试都没有成功。该项目将克服这一关键障碍，通过结合遗传定向稀疏标记的神经纤维与三维可视化和重建的味蕾。使用这些方法，我们将测试味觉神经元可以根据其形态分为亚型的假设（即，分支）和与特定类型的味觉受体细胞的连接。这些实验将揭示味觉细胞和神经纤维之间的联系是如何组织的。该项目中建立的方法可用于未来的研究，以了解1）形态亚型是否对应于特定的分子和/或功能亚型，2）中枢神经系统（CNS）中单个味觉神经元的分支，3）在发育过程中如何建立分支模式，以及4）正常的分支模式是否在损伤，疾病或化疗后重建。

 DESCRIPTION (provided by applicant: A general feature of sensory organization is that neurons can be divided into different types based on molecular, morphological, and functional characteristics. Whether this type of organization exists in the taste system is unclear. It is generally accepted that taste receptor cells exist as different types. The next critical step is to determine how these different taste receptor cell types can connect with the ganglion neurons that carry taste information to the brain. Because peripheral gustatory axons invade the tongue in fascicles, with individual axons intertwining at every level, past attempts at reconstructing single fibers have not been successful. This project will overcome this critical barrier by combining genetically-directed sparse labeling of nerve fibers with three-dimensional visualization and reconstruction in taste buds. Using these approaches, we will test the hypothesis that gustatory neurons can be divided into subtypes based on their morphology (i.e., branching) and connectivity with specific types of taste receptor cells. These experiments will reveal how connections between taste cells and nerve fibers are organized. The approaches established in this project can be used in future studies to understand 1) if morphological subtypes correspond to specific molecular and/or functional subtypes, 2) the branching of individual taste neurons in the central nervous system (CNS), 3) how branching patterns are established during development, and 4) whether normal branching patterns are reestablished following injury, disease, or chemotherapy.