Neural Mechanisms of Landmark-based Navigation

 描述（由申请人提供）：我们存在的一个基本方面是我们在空间中移动的事实。我们不会随机地这样做;相反，我们使用各种不同的策略来有效地达到我们的导航目标。其中一种策略是基于地标的导航（LBN），这是使用稳定的地标来确定相对于世界持久空间结构的位置和方向。当前的申请描述了一个研究项目的竞争性更新，在该项目中，我们使用功能性磁共振成像（fMRI）、经颅磁刺激（TMS）和认知行为测试来了解LBN背后的神经系统。根据我们已经开发的理论方案，LBN涉及三个认知机制：地标识别机制，定位/定向机制和路径规划机制。在最初的资助期间，我们使用多体素模式分析（MVPA）的功能磁共振成像数据，以证明海马旁位置区（PPA）支持地标识别和压后复合体（RSC）支持本地化/方向。这些结果表明，参与LBN的神经网络可以细分为与三种认知机制相关的功能子系统。我们在下一个资助期的目标是利用这些发现作为跳板，了解LBN系统的机械操作，并将调查扩展到包括路线规划。目标1是描述PPA中地标识别机制的信息处理功能并识别其功能输入。目的2是了解RSC如何使用外部特征和自我中心的经验来调解本地化/定向。目的3是识别和表征支持RSC和内侧颞叶（MTL）的路线规划的神经机制。如果成功，这项研究将导致基于地标导航的神经基础的详细理论。这些知识将在两个领域产生重要的健康影响。首先，了解LBN的基础机制对于制定康复策略和导航辅助设备至关重要， 盲人其次，由于研究的大脑区域通常在神经退行性疾病（如阿尔茨海默氏症）的早期受到影响，因此有关这些系统的知识将有助于诊断和管理这些疾病。

 DESCRIPTION (provided by applicant): A fundamental aspect of our existence is the fact that we move through space. We do not do so randomly; rather, we use a variety of different strategies to reach our navigational goals efficiently. One such strategy is landmark-based navigation (LBN), which is the use of stable landmarks to determine one's location and orientation relative to the enduring spatial structure of the world. The current application describes a competing renewal of a research program in which we use functional magnetic resonance imaging (fMRI), transcranial magnetic stimulation (TMS), and cognitive behavioral testing to understand the neural systems that underlie LBN. Under the theoretical scheme we have developed, LBN involves three cognitive mechanisms: a landmark recognition mechanism, a localization/orientation mechanism, and a route planning mechanism. During the initial funding period, we used multivoxel pattern analysis (MVPA) of fMRI data to demonstrate that the parahippocampal place area (PPA) supports landmark recognition and the retrosplenial complex (RSC) supports localization/orientation. These results indicate that the neural network involved in LBN can be fractionated into functional subsystems tied to the three cognitive mechanisms. Our goals in the next funding period are to use these discoveries as a springboard to understand the mechanistic operation of the LBN system and to extend the investigation to encompass route planning. Aim 1 is to delineate the information processing functions of the landmark recognition mechanism in the PPA and to identify its functional inputs. Aim 2 is to understand the how the RSC uses external features and egocentric experience to mediate localization/orientation. Aim 3 is to identify and characterize the neural mechanisms that support route planning in RSC and the medial temporal lobe (MTL). If successful, this research will result in a detailed theory of the neural basis of landmark-based navigation. This knowledge will have important health implications in two domains. First, understanding the mechanisms that underlie LBN is critical for the development of rehabilitation strategies and navigational aids for the blind. Second, because the brain regions investigated are often impacted early in neurodegenerative diseases such as Alzheimer's dementia, the knowledge gained about these systems will be useful for diagnosing and managing these diseases.