Spatial Codes Across the Medial Entorhinal Cortex for Memory and Navigation

大脑的核心功能是创造来自外部的刺激和经验的内部表征 引导行为的世界。在这里，我们检查了潜在的神经表示的电路机制 外部空间，一种对空间记忆和导航至关重要的表征，并受到神经退行性疾病的影响 和精神疾病。表示空间的神经基础在一定程度上取决于 内侧嗅觉皮质，将外部环境转换为内部空间地图。该决议 空间的内嗅神经映射图是按地形组织的，空间的放电率调谐曲线 定向神经元沿背侧至腹侧内嗅轴递增。这一地形具有 建议允许背侧和腹侧内嗅神经编码支持不同的行为，其中背侧 区域在空间学习中发挥着更大的作用。而我们之前的工作表明，背侧到腹侧 内嗅觉表征的空间尺度中的梯度影响空间记忆，即背侧 与腹侧神经编码相比，空间位置编码作为离散或协调的回路来支持空间记忆 或者导航仍然不完全被理解。在这里，我们建议使用硅来结合电生理学 行为老鼠的空间和记忆任务的探针。到目前为止，电生理方法必须 与访问腹侧皮质区域的困难和有限的记录通道数作斗争，导致 缺乏将内嗅神经元的活动同时考虑到背侧的研究。 腹轴。然而，新版本的硅探测器使我们能够记录数百(500)个神经元 几乎同时沿着小鼠内嗅觉皮质的整个长度。这与虚拟现实任务相结合 可以快速整合不同的感官和非量度(正面或负面刺激)提示，这将使 美国将揭示跨越背-腹内嗅轴的神经活动是如何在了解到 重要的环境特征以及这些信息是如何通过内嗅觉结构传递的 驱动人们的行为。深入了解这些字体将为我们提供一个全新的理解 空间的内脏地图支持空间记忆和导航。

A central function of the brain is to create internal representations of stimuli and experiences from the outside world to guide behavior. Here, we examine the circuit mechanisms underlying the neural representation of external space, a representation essential to spatial memory and navigation, and impacted by neurodegenerative and psychiatric diseases. The neural basis for the representation of space depends, in part, on circuits in the medial entorhinal cortex, which translate the external environment into an internal map of space. The resolution of the entorhinal neural map of space is topographically organized, with the firing rate tuning curves of spatial and directional neurons progressively increasing along the dorsal to ventral entorhinal axis. This topography has been proposed to allow dorsal versus ventral entorhinal neural codes to support different behaviors, with dorsal regions playing a larger role in spatial learning. While our previous work revealed that the dorsal to ventral gradient in the spatial scale of entorhinal representations impacts spatial memory, the degree to which dorsal versus ventral neural codes for spatial position act as discrete or coordinated circuits to support spatial memory or navigation remains incompletely understood. Here, we propose to combine electrophysiology using silicon probes with spatial and memory tasks in behaving mice. Until now, electrophysiological approaches had to contend with the difficulty of accessing ventral cortical regions and limited recording channel counts, resulting in a lack of studies in which the activity of entorhinal neurons were simultaneously considered across the dorsal- ventral axis. However, new versions of silicon probes have allowed us to record hundreds (>500) of neurons simultaneously along nearly the entire length of mouse entorhinal cortex. This, combined with virtual reality tasks that can rapidly incorporate a diverse set of sensory and non-metric (positive or negative stimuli) cues, will enable us to reveal how neural activity across the dorsal-ventral entorhinal axis is restructured after learning about important environmental features and how this information is then communicated across the entorhinal structure to drive behavior. Achieving significant insight along these fonts will provide a novel understanding of how entorhinal maps of space support spatial memory and navigation.