How does our brain tell us where we are based on what we see and hear? - Neuronal basis of cross-modal sensory integration for navigation

已经发现了几个空间细胞，包括海马区的定位细胞和内侧内嗅皮层的网状细胞。当动物探索环境时，这些细胞的活动为它提供了一种内部空间的表征。然而，一个尚未解决的关键问题是空间细胞如何整合多种感觉输入(如视觉、听觉、嗅觉等)以形成空间表征。虚拟现实(VR)为研究空间认知提供了强大的工具，允许进行现实世界中不可能的环境操作。我们最近为小鼠开发了一个二维VR(2D VR)系统，主要是视觉和运动/本体感觉输入，允许接近真实世界的空间表征。这个项目的目标是研究在空间导航过程中跨通道的感觉输入的整合。特别是，我们的目标是1)开发一种新的2D VR，其中视觉和听觉线索都可以单独控制和操纵，并训练动物在这种多感官VR中导航。2)描述这种多感觉VR中空间细胞的活动，特别是这些空间细胞相对于它们对感觉输入的反应的地形图。3)研究这些空间单元如何相互作用，以整合视觉和听觉输入，形成统一的空间表征。将使用的主要技术包括使用四极管和神经像素探针的在体电生理单位记录，以及在体双光子成像。理论模型将建立在实验结果的基础上，用来解释实验结果，并对未来的方向做出进一步的预测和假设。实验将主要由一级主管监督，而建模将主要由二级主管指导。工作将在QMUL和UCL进行。

Several spatial cells have been discovered, including place cells in the hippocampus and gridcells in the medial entorhinal cortex. The activity of these cells provides an animal with aninternal representation of space as it explores an environment. However, a key unsolvedproblem is how spatial cells integrate multiple sensory inputs (such as visual, auditory,olfactory, etc) in order to form spatial representations.Virtual reality (VR) offers a powerful tool for investigating spatial cognition, allowingenvironmental manipulations that are impossible in the real world. We have recentlydeveloped a two-dimensional VR (2D VR) system for mice with mainly visual andmotor/proprioceptive inputs, allowing a close approximation of spatial representation in thereal world.The goal of this project is to study the integration of sensory inputs across modalities duringspatial navigation. In particular we aim to 1) Develop a new 2D VR, where both visual andauditory cues can be individually controlled and manipulated, and train animals to navigatein this multisensory VR. 2) Characterise activity of spatial cells in this multisensory VR, inparticular the topography of these spatial cells with respect to their response to sensoryinputs. 3) Examine how these spatial cells interact in order to integrate visual and auditoryinputs, forming a unified spatial representation. The primary techniques that will be usedinclude in vivo electrophysiological single-unit recording using tetrodes and Neuropixelprobes, as well as in vivo 2-photon imaging. Theoretical models will be constructed based onthe experimental results, which will be used to explain experimental outcomes and makefurther predictions and hypotheses for future directions.Experiments will be supervised mainly by the primary supervisor, while the modelling will beguided primarily by the secondary supervisor. Work will be carried out in both QMUL and UCL.