Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA, USA.
Washington National Primate Research Center, Seattle, WA, USA.
Nat Rev Neurosci. 2021 Oct;22(10):637-649. doi: 10.1038/s41583-021-00499-9. Epub 2021 Aug 27.
Entorhinal cortical grid cells fire in a periodic pattern that tiles space, which is suggestive of a spatial coordinate system. However, irregularities in the grid pattern as well as responses of grid cells in contexts other than spatial navigation have presented a challenge to existing models of entorhinal function. In this Perspective, we propose that hippocampal input provides a key informative drive to the grid network in both spatial and non-spatial circumstances, particularly around salient events. We build on previous models in which neural activity propagates through the entorhinal-hippocampal network in time. This temporal contiguity in network activity points to temporal order as a necessary characteristic of representations generated by the hippocampal formation. We advocate that interactions in the entorhinal-hippocampal loop build a topological representation that is rooted in the temporal order of experience. In this way, the structure of grid cell firing supports a learned topology rather than a rigid coordinate frame that is bound to measurements of the physical world.
内嗅皮层栅格细胞以周期性模式发射，这种模式覆盖了整个空间，这表明存在一个空间坐标系。然而，栅格模式的不规则性以及栅格细胞在空间导航以外的环境中的反应，给内嗅皮层功能的现有模型带来了挑战。在这个观点中，我们提出，海马体的输入为网格网络提供了一个关键的信息驱动，无论是在空间还是非空间环境中，特别是在显著事件周围。我们基于以前的模型，其中神经活动在时间上通过内嗅皮层-海马体网络传播。网络活动中的这种时间连续性表明，时间顺序是海马体结构产生的表示的必要特征。我们主张，内嗅皮层-海马体环路中的相互作用构建了一种拓扑表示，这种表示根植于经验的时间顺序。通过这种方式，栅格细胞发射的结构支持一种学习到的拓扑结构，而不是与物理世界测量绑定的刚性坐标框架。
