Duncan Stephen, Kuruvilla Maneesh V, Thompson Benjamin, Bush Daniel, Ainge James A
School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, South Street, St Andrews KY16 9JP, UK; Department of Psychology & Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN 47405, USA.
School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, South Street, St Andrews KY16 9JP, UK; Wicking Dementia Research Centre, University of Tasmania, 17 Liverpool Street, Hobart, TAS 7001, Australia.
Curr Biol. 2025 Oct 6;35(19):4810-4819.e5. doi: 10.1016/j.cub.2025.08.011. Epub 2025 Sep 18.
Grid cells within the medial entorhinal cortex (MEC) exhibit a regular hexagonal pattern of firing fields, which has been hypothesized to provide a universal spatial metric, supporting spatial memory and navigation. This could be used to support a cognitive map, our internal representation of external space, and consistent with this, disruption of the MEC impairs spatial memory and place cell anchoring to external visual cues. However, the highly regular and repetitive nature of the firing fields in grid cells is also ideally suited to support path integration. Indeed, genetic silencing of stellate cells in MEC results in impaired distance estimation, supporting the MEC's role in path integration. However, few studies have examined the role of grid cell firing during active navigation. Several studies have reported that manipulation of environmental cues, recent experience, and reward location distort the grid signal, but most relevant here is that the grid signal distorts in polarizing environments, such as trapezoids. If grid cells support distance estimation and path integration, then disruption of the grid regularity, such as that seen in polarized environments, should impair these processes. Here, we report that both rats and humans have impaired distance estimation in polarized environments. Grid regularity was again reported to be distorted in polarized environments, and this was correlated with impaired distance estimation in rats. Grid regularity was also distorted by recent experience. These findings are consistent with grid cells supporting distance estimation in navigation.
内嗅皮层（MEC）中的网格细胞呈现出规则的六边形放电野模式，据推测这种模式提供了一种通用的空间度量，支持空间记忆和导航。这可以用来支持认知地图，即我们对外部空间的内部表征，与此一致的是，MEC的破坏会损害空间记忆以及位置细胞与外部视觉线索的锚定。然而，网格细胞放电野高度规则和重复的特性也非常适合支持路径整合。事实上，MEC中星状细胞的基因沉默会导致距离估计受损，这支持了MEC在路径整合中的作用。然而，很少有研究考察主动导航过程中网格细胞放电的作用。几项研究报告称，对环境线索、近期经历和奖励位置的操纵会扭曲网格信号，但在此最相关的是，在极化环境（如梯形环境）中网格信号会发生扭曲。如果网格细胞支持距离估计和路径整合，那么在极化环境中看到的网格规律性破坏，应该会损害这些过程。在这里，我们报告大鼠和人类在极化环境中距离估计都会受损。据再次报道，在极化环境中网格规律性会被扭曲，并且这与大鼠距离估计受损相关。近期经历也会扭曲网格规律性。这些发现与网格细胞在导航中支持距离估计一致。
