Vector Trace cells in the Subiculum of the hippocampal formation

海马结构下托中的矢量追踪细胞

• 批准号: BB/T014768/1
• 负责人: Colin Lever
• 金额: $ 48.47万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FT014768%2F1
• 关键词: Vector; Trace; cells; Subiculum; hippocampal

It is well established that the hippocampus supports spatial memory, navigation, planning, and imagination. Understanding how the hippocampus supports these functions is a major goal of intense, high-profile research globally. Here, we focus on a particular kind of spatial memory: remembering how far away and in what direction space-defining cues are located. This is called vector memory, and we think it is crucial to hippocampal function.Theoretical and empirical work has indicated that spatial mapping relies, broadly speaking, on two kinds of sensory inputs: one derived from self-motion cues, one from external environmental cues. Regarding self-motion, we can get some idea of where we are by estimating how far we have moved and in what direction, for instance from clues such as the motor and sensory systems informing us of the vigour and number of strides taken, and the degree of stride extension. Of course, the spaces around us are not 'empty', but filled with various external cues such as boundaries, objects and goals (like home bases). To navigate effectively, an animal must also encode how far away and in what direction such space-defining external cues are located. Cognitive processes such as path-planning and imagination entail the ability to remember such vector representations, but evidence that there are neurons that can provide such vector memory has been lacking.Importantly, then, we have recently found exactly such evidence of vector memory: a novel neuron type, which we call the Vector Trace cell (VTC), located in a region of the hippocampal formation called the subiculum. VTCs remember the distance and direction to an object for hours after that object is removed. We suspect that at least some VTCs can remember this for days, which we will test. It seems likely that VTCs provide memories for computing the spatial relationships between an animal and multiple cues (or between different cues), freed from the constraints of having to directly perceive those cues. This enables more powerful spatial planning and imaginative cognition than would be the case for a system that could not remember these spatial relationships. Indeed we speculate there might be some cognitive functions that are not obviously spatial, but rely on vector coding in more than one dimension, that VTCs could support, if the input to them was for example verbal information.Clearly, if we want to understand exactly how hippocampus supports spatial memory, navigation, planning, and imagination, which is intensively researched globally, then we will need to understand how the hippocampus produces vector-based spatial memory. This cannot be achieved without appreciating the particular contribution of the subiculum, where we have discovered Vector Trace cells, and which is a key output region of the hippocampal formation. In humans at least, it may be the most crucial hippocampal region for interacting with the rest of the brain in a network called the 'default mode network'. Autobiographical memories, creative thought, daydreaming, imagination and future-oriented speculation and plans are all thought to be highly dependent upon this 'default mode network'. We suspect that vector-based cognition and memories support these wider memory-based and creative functions. This grant aims to deliver a step-change in the understanding of hippocampal vector coding by delivering insights into: how the subiculum is organised functionally into different divisions, with one of these divisions supporting vector memory; the mechanisms of how individual vector trace cells generate vector coding and form and maintain vector memories, and how long this memory lasts; and finally how vector coding of external cues influences spatial mapping that is reliant, for its moment-to-moment activity, on self-motion.

海马体支持空间记忆、导航、计划和想象力，这一点已经得到了很好的证实。了解海马体如何支持这些功能是全球范围内紧张，高调研究的主要目标。在这里，我们专注于一种特殊的空间记忆：记住空间定义线索的距离和方向。这被称为向量记忆，我们认为它对海马体的功能至关重要。理论和实验研究表明，空间映射依赖于两种感觉输入：一种来自自我运动线索，一种来自外部环境线索。关于自我运动，我们可以通过估计我们已经移动了多远以及向哪个方向移动来了解我们所处的位置，例如，从运动和感觉系统等线索告诉我们所采取的步伐的力度和数量，以及步幅扩展的程度。当然，我们周围的空间并不是“空的”，而是充满了各种外部线索，如边界，物体和目标（如家庭基地）。为了有效地导航，动物还必须编码这些定义空间的外部线索的距离和方向。路径规划和想象等认知过程需要记忆这些向量表征的能力，但一直缺乏证据表明存在能够提供这种向量记忆的神经元，重要的是，我们最近发现了这种向量记忆的证据：一种新的神经元类型，我们称之为向量追踪细胞（VTC），位于海马结构的一个称为下托的区域。VTC在物体被移除后的几个小时内记住物体的距离和方向。我们怀疑至少有一些VTC可以记住这几天，我们将进行测试。VTC似乎提供了计算动物和多个线索之间（或不同线索之间）空间关系的记忆，摆脱了必须直接感知这些线索的限制。这使得更强大的空间规划和想象力的认知比系统，不能记住这些空间关系的情况下。事实上，我们推测可能有一些认知功能并不明显是空间的，但依赖于多个维度的向量编码，VTC可以支持这些功能，如果输入它们的是例如言语信息。显然，如果我们想确切地了解海马体如何支持空间记忆，导航，规划和想象力，这在全球范围内得到了深入研究，那么我们就需要了解海马体是如何产生矢量空间记忆的。如果不重视下托的特殊贡献，就无法实现这一点，我们在下托发现了Vector Trace细胞，它是海马结构的关键输出区域。至少在人类中，它可能是在一个称为“默认模式网络”的网络中与大脑其他部分相互作用的最关键的海马区域。自传体记忆、创造性思维、白日梦、想象力和面向未来的推测和计划都被认为高度依赖于这种“默认模式网络”。我们怀疑，基于矢量的认知和记忆支持这些更广泛的基于记忆的创造性功能。该基金旨在通过深入了解海马体矢量编码的理解来实现一个步骤的变化：下托如何在功能上组织成不同的部门，其中一个部门支持矢量记忆;单个矢量跟踪细胞如何产生矢量编码并形成和维持矢量记忆的机制，以及这种记忆持续多久;最后，外部线索的矢量编码如何影响空间映射，这是依赖于它的时刻到时刻的活动，对自我运动。

项目成果

Frequency matters: how changes in hippocampal theta frequency can influence temporal coding, anxiety-reduction, and memory.

• DOI: 10.3389/fnsys.2022.998116
• 发表时间: 2022
• 期刊: FRONTIERS IN SYSTEMS NEUROSCIENCE
• 影响因子: 3
• 作者: Hines, Miranda;Poulter, Steven;Douchamps, Vincent;Pibiri, Francesca;McGregor, Anthony;Lever, Colin
• 通讯作者: Lever, Colin

Neural correlates of distinct levels of predatory threat in dorsal periaqueductal grey neurons.

背侧导水管周围灰色神经元中不同捕食威胁水平的神经相关性。

• DOI: 10.1111/ejn.15633
• 发表时间: 2022
• 期刊: The European journal of neuroscience
• 作者: Bindi RP