Neural Mechanisms of Landmark-based Navigation

 描述(申请人提供)：我们存在的一个基本方面是我们在太空中移动的事实。我们这样做不是随机的；相反，我们使用各种不同的策略来有效地实现我们的导航目标。其中一种策略是基于地标的导航(LBN)，它使用稳定的地标来确定一个人相对于世界持久空间结构的位置和方向。目前的申请描述了一项研究计划的竞争性更新，在该计划中，我们使用功能磁共振成像(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。在我们提出的理论方案下，LBN涉及三种认知机制：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，我们使用功能磁共振数据的多体素模式分析(MVPA)来证明，海马旁区域(PPA)支持标志性识别，而脾后复合体(RSC)支持定位/定向。这些结果表明，LBN所涉及的神经网络可以细分为与这三种认知机制相联系的功能子系统。我们在下一个资助期的目标是以这些发现为跳板，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，并确定其功能输入。目标2是了解RSC如何使用外部特征和以自我为中心的经验来调节本地化/定向。目的3是识别和描述支持RSC和内侧颞叶(MTL)路径规划的神经机制。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。这一知识将在两个领域产生重要的健康影响。首先，了解LBN的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，由于所研究的大脑区域通常在阿尔茨海默氏症等神经退行性疾病的早期受到影响，因此获得的关于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.