The role of the head direction cell circuit in behavioural demonstrations of direction learning

当一个人走出地铁站时，他做的第一件事就是环顾四周并确定方向，因为知道你在哪里（例如，在Main和Pine街的拐角处）并不能帮助你开始下一段旅程，除非你也知道你的方向。当动物的头部指向一个特定的方向时，头部方向细胞就会放电，这被认为是这种方向感或方位感的基础。定向对空间学习的影响、它在记忆编码中的作用以及它在许多涉及导航的神经结构中的表现都揭示了定向的重要性。头部方向细胞比其他类型的空间细胞（如位置细胞和网格细胞）更早地以成人的方式放电，这一事实导致了人们的猜测，即头部方向细胞在哺乳动物的大脑中建立了整个空间网络。我在实验室的工作强化了这样一种信念，即方向学习是解决许多空间问题的基础，而这些问题以前被归因于位置学习。我的研究项目的目标是确定哪些头部方向细胞有助于方向学习和空间导航。如果头部方向细胞是动物方向感的神经表征，那么破坏头部方向细胞回路中的信息流应该会破坏方向学习的行为演示。本提案中概述的研究将检查大鼠和小鼠的头部方向细胞回路的永久损伤和暂时失活对空间任务的影响，其中方向方向是解决问题的关键。更好地了解头部方向细胞的功能意义及其在众多大脑区域中的存在将有助于使导航模型更加完整并推进空间认知领域。

The first thing a person does when exiting a subway station is to look around and get oriented, because knowing where you are (e.g., at the corner of Main and Pine Streets) does not help you start the next leg of your journey unless you also know your heading. Head direction cells fire when an animal’s head is pointed in a particular direction and are thought to underlie this sense of direction or orientation. The importance of orientation has been revealed by its impact on spatial learning, its role in the encoding of memories, and its representation in many neural structures involved in navigation. The fact that head direction cells fire in an adult-like fashion earlier than other types of spatial cells (i.e., place and grid cells) has led to speculation that head direction cells set up the entire spatial network in the mammalian brain. Work in my lab has strengthened the belief that direction learning underlies the solution to many spatial problems previously attributed to place learning. The goal of my research program is to determine what head direction cells contribute to direction learning and spatial navigation. If head direction cells are the neural representation of an animal’s sense of direction, then disrupting the flow of information within the head direction cell circuit should disrupt behavioral demonstrations of direction learning. The research outlined in this proposal will examine the effects of permanent lesions and temporary inactivation of select components of the head direction cell circuit in rats and mice on spatial tasks where directional heading is key to problem solution. A better understanding of the functional significance of head direction cells and their presence in a multitude of brain regions will serve to make models of navigation more complete and advance the field of spatial cognition.