Shamim K M, Scalia F, Tóth P, Cook J E
Department of Anatomy and Developmental Biology, University College London, U.K.
Vis Neurosci. 1997 Nov-Dec;14(6):1109-27. doi: 10.1017/s0952523800011810.
Population-based studies of ganglion cells in retinal flatmounts have helped to reveal some of their natural types in mammals, teleost fish and, recently, the aquatic mesobatrachian frog Xenopus laevis. Here, ganglion cells of the semiterrestrial neobatrachian frogs Rana esculenta and Rana pipiens have been studied similarly. Ganglion cells with large somata and thick dendrites could again be divided into three mosaic-forming types with distinctive stratification patterns. Cell dimensions correlated inversely with density, being smallest in the visual streak. Cells of the alpha a mosaic (< 0.2% of all ganglion cells) had the largest somata at each location (often displaced) and their trees were confined to one shallow plane within sublamina a of the inner plexiform layer. In regions of high regularity, many trees were symmetric. Elsewhere, asymmetric, irregular trees predominated and their dendrites, although sparsely branched, achieved consistent coverage by intersecting in complex ways. Cells of the alpha ab mosaic were more numerous (approximately 0.7%) and had large somata, smaller (but still large) trees, and dendrites that branched extensively in two separate shallow planes in sublaminae a and b. The subtrees did not always match in symmetry, and each subtree tessellated independently with its neighbors. Cells of the alpha c mosaic (approximately 0.1%) had large, orthotopic somata and large, sparse trees (often asymmetric and irregular) close to the ganglion cell layer. Nearest-neighbor analyses and spatial correlograms confirmed that each mosaic was regular and independent. Densities, proportions, sizes, and mosaic statistics are tabulated for all three types, which are compared with types defined by size and symmetry in R. pipiens, by discriminant analysis in R. temporaria, by physiological response in both, and by mosaic analysis in Xenopus and several teleosts. The variable stratification of these otherwise similar types across species is consistent with other evidence that stratification may be determined, in part, by functional interactions.
基于群体的视网膜平铺标本中神经节细胞的研究，有助于揭示哺乳动物、硬骨鱼以及最近发现的水生中蛙类非洲爪蟾体内神经节细胞的一些自然类型。在此，对半陆栖新蛙类食用蛙和豹蛙的神经节细胞进行了类似研究。具有大细胞体和粗树突的神经节细胞可再次分为三种形成镶嵌图案的类型，它们具有独特的分层模式。细胞大小与密度呈负相关，在视觉条纹处最小。α a 镶嵌型细胞（占所有神经节细胞的比例小于 0.2%）在每个位置都具有最大的细胞体（通常位置偏移），其树突局限于内网状层 a 亚层内的一个浅平面。在高度规则的区域，许多树突是对称的。在其他地方，不对称、不规则的树突占主导，尽管其分支稀疏，但通过复杂的交叉方式实现了一致的覆盖。α ab 镶嵌型细胞数量更多（约 0.7%），具有大细胞体、较小（但仍然较大）的树突，并且树突在 a 和 b 亚层的两个单独浅平面中广泛分支。子树的对称性并不总是匹配，并且每个子树都与其相邻子树独立镶嵌。α c 镶嵌型细胞（约 0.1%）具有大的、原位的细胞体以及靠近神经节细胞层的大的、稀疏的树突（通常不对称且不规则）。最近邻分析和空间相关图证实，每个镶嵌图案都是规则且独立的。列出了所有三种类型的密度、比例、大小和镶嵌统计数据，并将其与食用蛙中按大小和对称性定义的类型、欧洲林蛙中通过判别分析定义的类型、两者中通过生理反应定义的类型以及非洲爪蟾和几种硬骨鱼中通过镶嵌分析定义的类型进行比较。这些在其他方面相似的类型在不同物种间的可变分层与其他证据一致，即分层可能部分由功能相互作用决定。
