Vestibular Influences on Head Direction Cell Activity

前庭对头部方向细胞活动的影响

• 批准号: 6614167
• 负责人: BILL J YATES
• 金额: $ 14.85万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2005-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6614167
• 关键词: biological signal transduction; cell type; electrodes; electrophysiology; head; head movements; hippocampus; hypothalamus; laboratory rat; mature animal; neuronal transport; proprioception /kinesthesia; suid alphaherpesvirus 1; synapses; thalamus; vestibular nuclei; vestibular pathway

DESCRIPTION (provided by applicant): Head direction cells (HDC) located in several regions of the brain, including the anterior dorsal nucleus of the thalamus, postsubiculum, and lateral mammillary nuclei, provide the neural substrate for the determination of directional heading. Although activity of HDC is influenced by various sensory signals and internally generated cues, lesion studies and some anatomical and physiological evidence suggest that vestibular inputs are critical for the maintenance of directional sensitivity of these cells. In addition, relatively direct pathways have been proposed that could relay vestibular signals to brain areas containing HDC. However, vestibular inputs must be transformed considerably in order to signal head direction, and it is uncertain whether the simple circuitry that has been postulated to mediate vestibular influences on HDC can accomplish this transformation of signals. One purpose of the proposed research is to establish whether a relatively direct pathway links the vestibular nuclei with brain areas containing HDC. Specific Aim 1 tests the hypothesis that injection of the retrograde transneuronal tracer pseudorabies virus into two areas containing HDC, the anterior dorsal nucleus of the thalamus and lateral mammillary nuclei, results in labeling of neurons in the vestibular nuclei within short survival times, suggesting that only a few synapses separate HDC from vestibular nucleus neurons. Furthermore, definitive physiological studies have not been conducted to determine whether HDC respond similarly during active head rotations and passive rotations of the animal's body that activate labyrinthine receptors. If labyrinthine signals contribute to the directional sensitivity of HDC as substantially as suggested by prior lesion studies, then these cells should respond to high-frequency passive horizontal rotations that powerfully activate semicircular canal afferents. Specific Aim 2 tests the hypothesis that HDC have similar responses to active head rotations in the horizontal plane and passive rotations imposed using a turntable, including rotations delivered in the dark such that the predominant sensory information available is from the labyrinth. These experiments will establish whether the vestibular system plays a direct and powerful role in determining directional heading, and should advance understanding of the neural underpinnings of navigation. This work may also provide insights into potential effects of peripheral and central vestibular lesions on spatial cognition in humans.

描述（由申请人提供）：头部方向细胞（HDC）位于大脑的多个区域，包括丘脑前背核、下颌后核和外侧乳头核，为确定方向提供神经基础。尽管 HDC 的活性受到各种感觉信号和内部产生的线索的影响，但病变研究和一些解剖学和生理学证据表明，前庭输入对于维持这些细胞的方向敏感性至关重要。此外，还提出了相对直接的途径，可以将前庭信号传递到含有 HDC 的大脑区域。然而，前庭输入必须经过相当大的转换才能发出头部方向的信号，并且不确定被假设用于调节前庭对 HDC 影响的简单电路是否可以完成这种信号转换。拟议研究的目的之一是确定前庭核团与含有 HDC 的大脑区域是否有一条相对直接的通路连接。具体目标 1 检验了以下假设：将逆行经神经元示踪剂伪狂犬病病毒注射到含有 HDC 的两个区域（丘脑前背核和外侧乳头核），会在较短的存活时间内对前庭核中的神经元进行标记，这表明仅一些突触将 HDC 与前庭核神经元分开。此外，尚未进行明确的生理学研究来确定 HDC 在激活迷路受体的主动头部旋转和动物身体被动旋转期间是否有类似的反应。如果迷宫信号对 HDC 的方向敏感性的贡献与之前的病变研究所表明的一样，那么这些细胞应该对高频被动水平旋转做出反应，从而有力地激活半规管传入神经。具体目标 2 测试了这样的假设：HDC 对水平面内的主动头部旋转和使用转盘施加的被动旋转具有相似的响应，包括在黑暗中传递的旋转，以便可用的主要感官信息来自迷宫。这些实验将确定前庭系统在确定方向方面是否发挥直接而强大的作用，并应促进对导航神经基础的理解。这项工作还可以深入了解周围和中央前庭病变对人类空间认知的潜在影响。