CRCNS: US-German Collaboration: Auditory and Spatial Sequence Encoding in the Hippocampus

复杂的认知功能，如空间认知、语言发展和情景记忆，需要多种感官体验（如图像和声音）之间的联系，并要求这些联系被按顺序记忆。啮齿动物的海马体一直是理解记忆一系列空间位置的神经元机制的主要模型之一。然而，用于通过空间编码路径的机制是否与用于包含多种模态的编码序列的机制相同，这仍然是未知的。为了解决这个问题，听觉模态是特别有趣的，因为它提供了一种方法来呈现具有高时间精度的刺激序列，从而可以研究序列学习的时间限制。本研究调查了听觉专家啮齿动物的听觉序列学习，并测试蒙古沙鼠的海马体是否可以编码听觉刺激序列，其机制与用于空间序列的机制相似。将测试蒙古沙鼠是否存在位置场和θ相位进动，沙鼠海马中复杂的声音刺激是以空间独立的方式编码还是与动物的位置相关，以及声音序列的编码是否与用于编码空间序列的网络机制相关。这些问题将通过对行为动物海马主要细胞群的单单元记录来解决，实验将在虚拟现实设置中进行，该设置允许精确传递听觉刺激。在具有听觉特化的啮齿动物身上进行这些实验，可能会在解决海马体如何编码多模态序列方面取得重要进展。这项研究可以为序列编码的神经网络机制提供重要的见解，并可以更好地理解海马体对人类语言发展的贡献。该项目由计算神经科学合作研究和国际科学与工程办公室联合资助。德国教育和研究部（BMBF）正在资助一个伙伴项目。

Complex cognitive functions such as spatial cognition, language development, and episodic memory require associations between multiple sensory experiences, such as images and sound, and require that associations are remembered in sequence. The rodent hippocampus has been one of the leading models for understanding neuronal mechanisms for remembering a sequence of spatial locations. Yet, it remains unknown whether the mechanisms that are used for encoding a path through space are the same as those that are used for encoding sequences that contain multiple modalities. To address this question, the auditory modality is of particular interest since it provides a mean to present a sequence of stimuli with high temporal precision and thus a mean to investigate time constraints for sequence learning. The proposed research investigates auditory sequence learning in a rodent species that is a hearing-specialist and tests whether the hippocampus of Mongolian gerbils can encode sequences of auditory stimuli with mechanisms similar to those used for spatial sequences. It will be tested whether place fields and theta phase precession exist in Mongolian gerbils, whether complex sound stimuli are encoded in the gerbil hippocampus in a spatially-independent manner or in association with the location of the animal, and whether sound sequences are encoded with network mechanisms related to those that are used for encoding spatial sequences. These questions will be addressed with single-unit recording from hippocampal principal cell populations of behaving animals, and experiments will be conducted in a virtual reality setup that allows for the precise delivery of auditory stimuli. Performing these experiments in a rodent species with an auditory specialization might result in important advances in addressing how the hippocampus encodes multimodal sequences. This research can provide important insight into neural network mechanisms for sequence coding and can lead to a better understanding of the contribution of the hippocampus to language development in humans.This project is jointly funded by Collaborative Research in Computational Neuroscience and the Office of International Science and Engineering. A companion project is being funded by the German Ministry of Education and Research (BMBF).