マウスの尻尾を用いたバランス機能の解明

前言：对老鼠的研究表明，尾巴对平衡很重要。然而，这一假说从未在高分辨率运动捕捉中得到解决，实现这一运动程序的神经系统目前尚不清楚。在这里描述的项目中，我研究了前庭系统对尾部运动控制的功能作用，前庭系统在平衡运动反应方面起着重要作用。在上个财政年度，我解决了两个主要问题：(1)小鼠是否以及如何在脊线任务中利用尾巴保持平衡(2)脊髓中的尾部运动神经元是否接受前庭核团的投射。岭实验(1)：我们发现小鼠利用尾巴来适应较小的宽度有两种策略：尾部摆动幅度更大，尾巴更接近小鼠的滚动平面。我们推测，这最后一种策略允许小鼠在滚动平面上增加尾巴的有效长度。前庭投射到尾部MN上的标记(2)：这部分项目的目标是评估脊髓中的尾部运动神经元是否接受前庭核团的投射。在这个框架内，第一个实现的目标是识别脊髓中的尾部运动神经元(MN)池。为了确定MN池由多少个神经元组成，我肌肉注射霍乱毒素亚单位(CTB)。

Introduction: Studies in mice have suggested that the tail is important for balance. However this hypothesis has never been addressed with high resolution motion capture, and the neuronal system that implement this motor program is currently unknown. In the project described here, I study the functional role of the vestibular system, which plays an important role in balancing motor responses, for the motor control of the tail.In the last fiscal year, I addressed the two main questions:(1) whether and how mice use their tail to maintain balance in the ridge task(2) whether tail motoneurons in the spinal cord receive projections from the vestibular nuclei.Ridge experiment (1): We revealed that mice employ two strategies with their tails to adapt to the smaller widths: the tail swing amplitude is bigger, and the tail is positioned closer to the roll plane of the mouse. We speculate that this last strategy allows the mouse to increase the effective length of the tail in the roll plane.Labeling of vestibular projections onto tail MNs (2): The goal of this part of the project is to assess whether tail motoneurons in the spinal cord receive projections from the vestibular nuclei. Within this framework the first achieved objective was the identification of the tail motoneurons (MN) pool in the spinal cord. In order to identify the approximate number of neurons that the MN pool consists of, I injected intramuscularly cholera toxin subunit (CTb).