Sound Evoked Eye and Head Movements Mediated by Vestibulo-Collic and Vestibulo-Ocular Reflex (VOR, VCR) Pathways: a Physiological Basis for Noise Induced Vestibular Loss (NIVL)

 描述(申请人提供)：人类进化的标志之一是，我们可以用我们的手或工具来操纵物理世界，这些工具可以延伸或放大我们的前肢和手指的部分。这种手动灵活性与后顶叶皮质(PPC)的扩展共同进化，PPC包含了参与编程自愿运动、在多个参照系中对到达目标进行编码以及决策的区域。为了允许我们的身体与我们的物理环境交互，这些场还必须构建物理自我的内部模型：我们的身体的配置，我们的身体和外部物理对象之间的边界，以及当我们使用工具扩展我们的触角和手动能力时那个自我的暂时扩展。这种对自我在哪里和什么的理解，甚至对操纵物体并将其用作工具的能力，并不是从人类身上从头进化出来的，而是从可能存在于早期哺乳动物的简单网络中产生的。这项提议的首要目标是使用多层次的比较方法来确定与伸展和抓取相关的简单网络是如何被修改以产生与人类状况相关的复杂能力的。在四个重要的动物模型(大鼠、树鼠、原猴和猕猴)中，我们将使用电生理记录技术、皮质内微刺激(ICMS)和神经解剖学追踪技术来确定PPC中的同源区。我们和其他人已经提出，PPC产生的运动由PPC中发生的多感觉输入的整合来引导。在运动过程中，PPC运动区和运动特定区域的神经元协调它们的活动，以产生与上下文相关的目标获取和其他运动所必需的独特的身体、前肢和手姿势序列。这一假说将通过两种方式进行验证：(1)我们将可逆地失活猕猴和大鼠的运动(M1)皮层，并检查ICMS在PPC中引发的运动领域的影响；(2)我们将在自然的双手目标获取任务中，可逆地失活猕猴PPC中的M1和大脑皮层区域，以揭示这些皮质区如何协同工作，产生准确和上下文合适的到达和抓取。通过结合来自多个物种的连接、功能和行为数据，这些研究将提供对这些复杂的大脑网络在运动计划和执行中所起作用的丰富理解。

 DESCRIPTION (provided by applicant): One of the hallmarks of human evolution is the extraordinary degree to which we can manipulate the physical world with our hands or with tools that extend or amplify portions of our forelimb and digits. This manual dexterity coevolved with an expansion of posterior parietal cortex (PPC), which contains areas involved in programming voluntary movements, coding reach targets in multiple reference frames, and decision making. To allow our body to interact with our physical surroundings, these fields must also construct an internal model of the physical self: our body's configuration, the boundary between our body and external physical objects, and the temporary expansion of that self as we wield a tool that extends our reach and manual capabilities. Such comprehension of where and what the self is and even the ability to manipulate objects and use them as tools did not evolve de novo in humans, but rather emerged from simple networks likely to be present in early mammals. The overarching goal of this proposal is to use a multileveled comparative approach to determine how simple networks associated with reaching and grasping were modified to produce the sophisticated abilities associated with the human condition. In four important animal models (rats, tree shrews, prosimian galagos, and macaque monkeys) we will use electrophysiological recording techniques, intracortical microstimulation (ICMS), and neuroanatomical tracing techniques to define homologous areas in PPC. We, and others, have proposed that PPC generates movements guided by the integration of multisensory inputs occurring in PPC. During movements, neurons in motor areas and movement-specific domains of PPC coordinate their activity to generate unique sequences of body, forelimb and hand postures necessary for context-dependent target acquisition and other movements. This hypothesis will be tested in two ways: (1) We will reversibly deactivate motor (M1) cortex in macaque monkeys and rats and examine the effects on movement domains elicited by ICMS in PPC, and (2) We will reversibly deactivate M1 and cortical areas in PPC in macaque monkeys during a natural, bimanual target acquisition task to reveal how these cortical areas work together to generate accurate and contextually appropriate reaching and grasping. By combining connectional, functional, and behavioral data from multiple species, these studies will provide a rich understanding of the role of these complex brain networks in the planning and execution of movement.