Retrosplenial Cortex Interactions with Entorhinal Cortex and the Visual Anchoring of Spatial Representations

海马体(HPC)、内侧嗅觉皮质(MEC)和脾后皮质(RSC) 与记忆有关，所有三个结构的萎缩都是阿尔茨海默病的早期指标。在……里面 与记忆过程类似，这些结构对空间认知和其中的神经元都很重要 区域表现出空间上特定的激发。当动物占据 相对于远端视觉地标的环境。MEC神经元编码多种形式的空间信息， 包括栅格场，其中单个神经元在跨越整个脑区的多个等距位置活跃 并形成一个周期性的网格。关键是， 微血管内皮细胞空间模式功能障碍扰乱时序 HPC中的编码被认为是情节记忆的基础。 已知与空间相关的强健的MEC激发需要视觉信息，这些视觉信息可能通过 RSC.RSC形成强烈的兴奋性投射到该区域，与MEC一样，RSC神经元的放电可以 具有节奏性和空间周期性。此外，单个RSC神经元编码感觉、运动和空间 已知的调节MEC激活的变量。虽然我们知道RSC是视觉的一部分 处理网络中，关于RSC空间表示如何受 远端视觉提示或视觉相关的RSC激活如何反过来影响MEC的激活。给定 RSC和MEC之间的功能和解剖关系，探讨它们之间的联系和 此时的关节神经生理学动力学。 这一建议旨在加深我们对MEC和RSC在空间上的系统相互作用的理解 编码。建议的实验将分析视觉信息在RSC和MEC空间中的影响 通过实现可视提示操作来扩展或压缩相对 当老鼠执行视觉引导导航范例时，视觉地标之间的角度。此外， 拟议的实验将利用光遗传学专门抑制RSC向MEC的投射来测试 假设MEC视觉敏感度需要RSC输入。在这些实验中收集的数据将是 用于测试关于位置估计和MEC空间失真的计算建模预测 在转移到熟悉的远端线索的已知位置后的表征。

The hippocampus (HPC), medial entorhinal cortex (MEC), and retrosplenial cortex (RSC) are strongly implicated in memory, and atrophy of all three structures serves as an early indicator of Alzheimer's disease. In parallel to memory processes, these structures are important for spatial cognition and neurons within these regions exhibit spatially-specific firing. HPC place cells fire when an animal occupies an explicit location in the environment relative to distal visual landmarks. MEC neurons encode multiple forms of spatial information, including grid fields, wherein a single neuron is active at multiple, equidistant locations that span the entire environment and form a periodic grid. Critically, dysfunction of MEC spatial patterning disrupts sequential encoding in the HPC which is thought to underlie episodic memory. Robust MEC spatially-related firing is known to require visual information which is likely routed to the region via RSC. RSC forms a strong excitatory projection into the region, and like MEC, firing of RSC neurons can be rhythmic and exhibit spatial periodicity. Further, individual RSC neurons encode sensory, motor, and spatial variables that are known to modulate MEC activation. Although it is known that RSC is part of the visual processing network, little is known as to how RSC spatial representations are influenced by the arrangement of distal visual cues or how visually-related RSC activation in turn influences MEC activation. Given the functional and anatomical relationship between RSC and MEC, it is pertinent to explore their connectivity and joint neurophysiological dynamics at this time. This proposal seeks to further our understanding of systems interactions between MEC and RSC in spatial encoding. The proposed experiments will assay the influence of visual information in RSC and MEC spatial representations through the implementation of visual cue manipulations that expand or compress the relative angle between visual landmarks while rats perform a visually-guided navigation paradigm. Additionally, the proposed experiments will utilize optogenetics to specifically inhibit RSC projections into MEC to test hypotheses that RSC input is required for MEC visual sensitivity. Data collected in these experiments will be utilized to test computational modeling predictions about distortions to position estimation and MEC spatial representations following shifts to the known locations of familiar distal cues.