Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
Nat Rev Neurosci. 2019 Apr;20(4):193-204. doi: 10.1038/s41583-019-0125-5.
The mechanistic operation of brain regions is often interpreted by partitioning constituent neurons into 'cell types'. Historically, such cell types were broadly defined by their correspondence to gross features of the nervous system (such as cytoarchitecture). Modern-day neuroscientific techniques, enabling a more nuanced examination of neuronal properties, have illustrated a wealth of heterogeneity within these classical cell types. Here, we review the extent of this within-cell-type heterogeneity in one of the simplest cortical regions of the mammalian brain, the rodent hippocampus. We focus on the mounting evidence that the classical CA3, CA1 and subiculum pyramidal cell types all exhibit prominent and spatially patterned within-cell-type heterogeneity, and suggest these cell types provide a model system for exploring the organization and function of such heterogeneity. Given that the hippocampus is structurally simple and evolutionarily ancient, within-cell-type heterogeneity is likely to be a general and crucial feature of the mammalian brain.
脑区的机械操作通常通过将组成神经元划分为“细胞类型”来解释。从历史上看，这些细胞类型是根据它们与神经系统的大体特征（如细胞结构）相对应来广义定义的。现代神经科学技术使人们能够更细致地研究神经元特性，这表明这些经典细胞类型中存在着大量的异质性。在这里，我们回顾了哺乳动物大脑中最简单的皮质区域之一——啮齿动物海马体中这种细胞内异质性的程度。我们重点介绍了越来越多的证据表明，经典的 CA3、CA1 和 subiculum 锥体神经元类型都表现出显著的和空间模式化的细胞内异质性，并表明这些细胞类型为探索这种异质性的组织和功能提供了一个模型系统。鉴于海马体结构简单，进化古老，细胞内异质性可能是哺乳动物大脑的一个普遍而关键的特征。
