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

已经发现了一些空间细胞，包括海马中的位置细胞和内侧内嗅皮层中的网格细胞。当动物探索环境时，这些细胞的活动为动物提供了对空间的内部表征。然而，空间细胞如何整合多种感觉输入（如视觉、听觉、嗅觉等）以形成空间表征是一个尚未解决的关键问题，虚拟现实（VR）为研究空间认知提供了一个强有力的工具，它允许在真实的世界中不可能进行的环境操纵。我们最近开发了一个以视觉和运动/本体感觉输入为主的二维虚拟现实（2D VR）系统，用于模拟真实世界的空间表征，本项目的目的是研究空间导航过程中感觉输入的整合。具体来说，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)描述多感觉VR中空间细胞的活动特征，特别是这些空间细胞对感觉输入的反应。3)研究这些空间细胞如何相互作用，以整合视觉和视觉输入，形成一个统一的空间表示。主要技术包括使用四极和Neuropixel探针的体内电生理单单位记录，以及体内双光子成像。根据实验结果构建理论模型，用于解释实验结果，并对未来方向做出进一步的预测和假设。实验将主要由初级主管监督，而建模将主要由次级主管指导。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.