Dopaminergic amacrine cells in the inner nuclear layer and ganglion cell layer comprise a single functional retinal mosaic
Dopaminergic amacrine cells in the inner nuclear layer and ganglion cell layer comprise a single functional retinal mosaic
复制标题
DOI：
10.1002/cne.10891
复制
发表时间：
2003-11-17
影响因子：
2.5
通讯作者：
Reese, BE
中科院分区：
文献类型：
--
作者：
Eglen, SJ;Raven, MA;Reese, BE
许多类型的视网膜神经元以有序的方式分布在视网膜表面。事实上，在神经元群体中存在这种规律性，称为视网膜马赛克，可能是功能独立类型的视网膜神经元的定义特征。我们研究了雪貂视网膜内核层（INL）和神经节细胞层（GCL）中多巴胺能无长突细胞的空间分布，以确定每层中的细胞是否形成独立的视网膜镶嵌，作为它们是否应被视为两种独立类型的证据。雪貂视网膜含有约1，900个多巴胺能无长突细胞，其中27%位于GCL中，其余位于INL中。通过Voronoi域分析、自相关分析和完全空间随机性检验，发现INL细胞的分布具有统计规律性，而GCL细胞的分布不具有统计规律性。然而，通过使用互相关分析，这两组细胞被发现是空间依赖性的：在互相关图中检测到一个排除区，其大小与INL和GCL细胞的自相关图中发现的大小大致相同。如果INL和GCL中的多巴胺能无长突细胞是一个单一的常规群体的成员，仅在体细胞深度上不同，则这种模式是可以预期的。通过使用计算机模拟，我们直接测试了这一假设，证实了从总人口中随机分配27%产生的交叉相关图与生物镶嵌图无法区分。因此，我们的结论是，在这两个层的细胞形成一个单一的功能群体，那些在GCL似乎是错位。相对于视网膜内深度的躯体定位本身并不是功能分类的可靠指南。(C)2003 Wiley-Liss，Inc.
Many types of retinal neuron are distributed in an orderly manner across the surface of the retina. Indeed, the existence of such regularity amongst a population of neurons, termed a retinal mosaic, may be a defining feature of functionally independent types of retinal neuron. We have examined the spatial distribution of dopaminergic amacrine cells in the ferret retina both in the inner nuclear layer (INL) and in the ganglion cell layer (GCL) to determine whether the cells in each layer form an independent retinal mosaic as evidence of whether they should be considered as two separate types. Ferret retinas contain approximately 1,900 dopaminergic amacrine cells, of which 27% are located in the GCL, and the rest in the INL. Based on analysis of their Voronoi domains as well as autocorrelation analysis and tests for complete spatial randomness, we found that the distribution of INL cells was statistically regular, while that of the GCL cells was not. However, by using cross-correlation analysis, these two groups of cells were found to be spatially dependent: an exclusion zone was detected in the cross-correlogram of roughly the same size as that found in the autocorrelograms of both INL and GCL cells. Such a pattern would be expected if dopaminergic amacrine cells in the INL and GCL were members of a single regular population differing only in their somatic depth. By using computer simulations, we tested this hypothesis directly, confirming that a random assignment of 27% from the total population produces cross-correlograms that are indistinguishable from those of the biological mosaics. We conclude, therefore, that the cells in the two layers form a single functional population; those in the GCL appear to be misplaced. Somatic positioning with respect to depth within the retina is not, by itself, a reliable guide for functional classification. (C) 2003 Wiley-Liss, Inc.