Inertial and multisensory influences on entorhinal grid cells

项目总结 动物根据自我运动提示和外部参考进行导航，这有助于纠正错误 在路径整合中积累。内侧内嗅皮层(MEC)中的细胞编码方向、速度和 它们的输出可以代表路径整合的神经基础。前庭系统提供了 角运动和直线运动的信息，以及损伤研究表明，它可能对路径很重要 基于集成的导航。这是否以及如何做到这一点是一个谜。近年来，虚拟- 在探索导航电路时，现实(VR)已经成为一种时尚。值得注意的是，二维(2D)网格 头部固定的啮齿类动物在经历VR时，其属性会受到影响。这里要检验的假设是 这是因为惯性(前庭)信号与运动和视觉线索相冲突-- 与真实世界的导航形成对比，在现实世界中，来自前庭、视觉和其他方面的一致多感官提示 所有的模式都汇聚在一起，产生了在空间中运动的感觉。在VR中，只有视觉和 本体感觉提示存在，而前庭提示没有运动信号。来检验惯性的假设 在MEC中，运动线索是进行空间编码所必需的，我们构建了一种独一无二的VR设备(鼠标 头部固定并在安装在运动平台顶部的气垫泡沫塑料球上运动)， 它可以提供惯性加速。创造VR环境的视觉刺激以及 平台的移动既由鼠标的移动控制，也由由此产生的球旋转控制。 我们将在导航过程中监控网格细胞的活动，同时旋转和/或平移多感觉提示 独立和系统地操纵。我们的发现可能会彻底改变我们对 MEC中空间代码的性质和特性通过将不同的专业知识和两个分离的 (导航/MEC/海马区和前庭/多感官)社区。

PROJECT SUMMARY Animals navigate based on self-motion cues and external references, which serve to correct errors accumulated in path integration. Cells in the medial entorhinal cortex (MEC) encode direction, speed and position, and their output could represent the neural basis for path integration. The vestibular system provides information for angular and linear motion, and lesion studies have suggested that it may be important for path integration-based navigation. Whether and how this is done represents a mystery. In recent years, virtual- reality (VR) has become fashionable in exploring the navigation circuit. Remarkably, two-dimensional (2D) grid properties are compromised in head-fixed rodents experiencing VR. The hypothesis to be tested here is that this occurs because inertial (vestibular) signals are in conflict with locomotion and visual cues – which contrasts with real-world navigation where congruent multisensory cues from vestibular, visual and other modalities all converge to give rise to the sense of motion through space. In VR, only the visual and proprioceptive cues are present, while vestibular cues signal no motion. To test the hypothesis that inertial motion cues are necessary for space coding in the MEC, we have built a one-of-a-kind VR apparatus (mouse is head-fixed and locomoting on an air cushioned Styrofoam ball) that is mounted on top of a motion platform, which can provide inertial accelerations. The visual stimulus creating the VR environment as well as the movement of the platform are both controlled by the locomotion of the mouse and the resulting ball rotation. We will monitor grid cell activity during navigation, while rotation and/or translation multisensory cues are independently and systematically manipulated. Our findings could revolutionize our understanding of the nature and properties of the spatial code in MEC by bridging together diverse expertise and two segregated (navigation/MEC/hippocampus and vestibular/multisensory) communities.