Path Integration in the Rat Navigational System

描述（由申请人提供）：当老鼠在空间中导航时，神经元 位于整个边缘系统提供了一个抽象的表示 环境。提供这种类似地图的表示的单元分为两个 一般类别。其中一种类型称为“放置细胞”，只要 老鼠处于较大环境中的一个特定位置。各个地方 细胞有自己的高发射区域，因此对于每个点，动物 访问时，有一组独特的细胞将处于活动状态。另一种类型是 称为头部方向细胞。每当老鼠面对一个时，这些都会被触发 特定的方向，并且无论老鼠当前的位置或位置如何，都会这样做 行为状态。由于每个细胞都有自己的首选方向，因此存在一个 一组独特的方向单元，对每个可能的标题都有效。 以前的工作；已经表明，位置单元和头部方向单元 部分依赖于称为路径整合的过程，以某种方式“跟踪” 分别是老鼠的位置和方向。路径整合涉及 利用动物自身的运动来不断更新空间射击 模式。例如，如果老鼠从位置“A”开始，然后采取了一些 到达“B”的步骤，这个运动本身会以某种方式导致“A”位置 要关闭的单元格，以及要打开的“B”位置单元格。同样，如果动物 从“北”信号头部方向细胞的活动开始，然后 向右转 90 度，这个角运动本身会以某种方式转动 “北”头部方向单元格关闭，“东”头部方向单元格打开。 最近的数据表明，位置和头部方向系统可能各自具有 他们自己的路径集成电路位于特定的、确定的 边缘系统的脑干组成部分。拟议工作的目标将 1）从这些细胞核中记录以确定它们是否含有 被假设为神经路径整合所必需的信号 位置和头部方向细胞的网络模型，以及 2) 损害这些区域 并检查对其他部分的位置和头部方向细胞的影响 边缘系统。我们假设这些原子核的损伤会破坏所有 整个边缘系统的位置和方向信号。 如果证实这些原子核确实构成了假设的路径 集成电路，这将为未来的重要工作提供基础。 路径整合是一种复杂的神经计算，被认为是 复杂的认知绘图能力。此外，电路假设为 路径整合在形式上类似于许多其他假设的路径整合 认知功能，包括短期记忆和某些类型的视觉 感知。因此，路径积分电路的识别 位置和头部方向系统将允许对一种类型的详细研究 电路可能在几种类型的高级电路中发挥核心作用 认知功能。

DESCRIPTION (provided by applicant): As a rat navigates through space, neurons located throughout the limbic system provide an abstract representation of the environment. The cells which provide this map-like representation fall into two general categories. One type, known as Place cells, fires optimally whenever the rat is in one particular location within the larger environment. Each Place cell has its own region of high firing, so that for each spot the animal visits, there is a unique set of cells which will be active. The other type is known as Head Direction cells. Each of these fires whenever the rat faces one particular direction and will do so regardless of the rat's current location or behavioral state. Since each cell has its own preferred direction, there is a unique set of directional cells which are active for each possible heading. Previous work; has shown that both the Place cells and the Head Direction cells rely, in part, on a process known as path integration, to somehow "track" the rat's location and directional heading, respectively. Path integration involves the use of the animal's own movement to constantly update the spatial firing patterns. For example, if the rat begins at, location 'A', and then takes a few steps to arrive at 'B', this motion itself will, somehow, cause the 'A' Place cells to turn off, and the 'B' Place cells to turn on. Similarly, if the animal begins with activity in the 'north'-signaling Head Direction cells, and then turns 90 degrees to the right, this angular motion will, itself, somehow turn the 'north' Head Direction cells off, and the 'east' Head Direction cells on. Recent data suggest that the Place and Head Direction systems may each have their own path integration circuitry located within particular, identified brainstem components of the limbic system. The goal of the proposed work will be 1) to record from cells in these nuclei to determine whether they contain signals which have been postulated as necessary for path integration in neural network models of Place and Head Direction cells, and 2) to lesion these areas and examine the effects on Place and Head Direction cells in other parts of the limbic system. We postulate that lesions of these nuclei should destroy all Place and Directional signals throughout the limbic system. If it is verified that these nuclei do, in fact, constitute the postulated path integration circuitry, this will provide a basis for important future work. Path integration is a sophistocated neural computation thought to underly complex cognitive mapping abilities. In addition, the circuitry postulated for path integration is formally similar to that postulated for numerous other cognitive functions, including short term memory and certain types of visual perception. Thus the identification of the path integration circuitry for the Place and Head Direction systems would allow for detailed study of a type of circuit which is likely to play a central role in several types of higher cognitive function.