Neural Control of Head Stabilization and Tracking

描述(由申请人提供)：头颈电机系统在电机控制体系中占有独特的位置。根据行为背景的不同，它在三种截然不同的运动功能中扮演着重要的角色：头部稳定、跳动和平稳跟踪头部运动，以及自愿的、非视觉引导的头部运动。我们将集中于两个向颈部运动神经元的强烈下行投射：前庭脊髓神经元和网状脊髓神经元。为了开始填补我们对这些磁头控制电路特性的知识中的主要空白，我们提出了针对以下三个目标的实验。 1.描述和比较猴子用来执行前庭稳定头部运动、缓慢跟踪头运动和快速扫视头部运动的三维颈部肌肉活动模式。我们将寻找在执行一个动作时使用多种肌肉模式的证据。 2.探索单个逆行识别的前庭脊髓神经元和网状脊髓神经元在产生目标1中所研究的头部运动中的作用。神经元将根据它们携带的与眼睛和头部运动相关的信号的类型进行分类。我们将研究这些神经元如何实现大脑的能力，以抵消由自身产生的头部运动产生的前庭头部运动信号。我们还将寻找多个中央控制器驱动自愿头部运动的证据。 3.将神经解剖学示踪剂注入灵长类动物的颈髓、脑干网状结构或大脑皮质投射到前庭核团和网状结构的区域，以显示参与颈部运动控制的通路。 头部运动控制障碍是许多神经疾病的衰弱症状，包括中风、脑瘫、帕金森病和前庭神经病。通过增加我们对中枢神经系统如何控制头部的理解，这个项目应该会为更好地治疗这些疾病开辟道路。

DESCRIPTION (provided by applicant): The head-neck motor system occupies a unique place in the motor control hierarchy. Depending upon behavioral context, it plays an important role in three quite distinct motor functions: head stabilization, saccadic and smooth tracking head movements and voluntary, non-visually guided head movements. We will focus on two strong descending projections to neck motoneurons: vestibulospinal and reticulospinal neurons. To begin filling major gaps in our knowledge about properties of these head control circuits, we propose experiments directed at the following three aims. 1. Characterize and compare patterns of neck muscle activity that monkeys use to execute vestibular stabilizing head movements, slow tracking head movements and rapid saccadic head movements in three dimensions. We will look for evidence that multiple muscle patterns are used in executing a movement. 2. Explore the role of single antidromically identified vestibulospinal and reticulospinal neurons in generating the head movements studied in Aim 1. Neurons will be classified according to the types of eye- and head-movement related signals they carry. We will examine how these neurons implement the brain's ability to cancel out vestibular head movement signals that arise from self-generated head movements. We will also look for evidence that multiple central controllers drive voluntary head movements. 3. Inject neuroanatomical tracers into the cervical spinal cord, brainstem reticular formation or regions of cerebral cortex projecting to vestibular nuclei and reticular formation to visualize pathways involved in neck motor control in primates. Impaired control of head movement is a debilitating symptom of many neurological disorders including stroke, cerebral palsy, Parkinson's disease and vestibular neuropathy. By increasing our understanding of how the CNS controls the head, this project should open the way to better treatment of these disorders.