Famiglietti E V
Department of Anatomy, University of Calgary, Faculty of Medicine, Alberta, Canada.
J Comp Neurol. 1992 Oct 15;324(3):322-35. doi: 10.1002/cne.903240303.
The morphology, dendritic branching patterns, and dendritic stratification of retinal ganglion cells have been studied in Golgi-impregnated, whole-mount preparations of rabbit retina. Among a large number of morphological types identified, two have been found that correspond to the morphology of ON and ON-OFF directionally selective (DS) ganglion cells identified in other studies. These cells have been characterized in the preceding paper in terms of their cell body size, dendritic field size, and branching pattern. In this paper, the two kinds of DS ganglion cell are compared in terms of their levels of dendritic stratification. They are compared with each other and also with examples of class III.1 cells, defined in the preceding paper with reference to our previous studies. Studies employing computer-aided, 3D reconstruction of dendritic trees, as well as analysis of a pair of ON DS and ON-OFF DS ganglion cells with overlapping dendritic trees show that the two types of DS ganglion cell partly co-stratify in the middle of sublamina b (stratum 4). The report that some ON DS ganglion cells extend a few dendrites into sublamina a is confirmed. The study of pairs of ON-OFF DS ganglion cells and starburst amacrine cells with overlapping dendritic trees reveals a precise co-stratification of these two cell types, and many points of close apposition of starburst boutons with ON-OFF DS ganglion cell dendrites in both sublaminae of the inner plexiform layer (IPL). This is confirmed by high-resolution light microscopy and by electron microscopy. It is possible to conclude, therefore, that ON DS are also partly co-stratified with type b starburst (cholinergic) amacrine cells, and are apparently also partly co-stratified with type a starburst amacrine cells, when occasional dendrites rise to that level. The co-stratification of the two kinds of DS ganglion cell is consistent with the sharing of some inputs in common, including some cone bipolar cell inputs. The co-stratification of both with starburst amacrine cells agrees with the physiological demonstration of the powerful pharmacological effects upon ON and ON-OFF DS ganglion cells reported for cholinergic agonists. The major difference in the dendritic stratification of bistratified ON-OFF DS ganglion cells and generally unistratified ON DS ganglion cells is consistent with the bisublaminar organization of ON and OFF pathways in the IPL. The problem of occasional branches of ON DS cells in sublamina a is discussed in terms of a threshold for OFF responses.(ABSTRACT TRUNCATED AT 400 WORDS)
在高尔基染色的兔视网膜整装标本中，对视网膜神经节细胞的形态、树突分支模式和树突分层进行了研究。在鉴定出的大量形态学类型中，发现了两种与其他研究中鉴定出的ON和ON-OFF方向选择性（DS）神经节细胞的形态相对应。在前一篇论文中，已根据这些细胞的胞体大小、树突野大小和分支模式对其进行了描述。在本文中，从树突分层水平方面对这两种DS神经节细胞进行了比较。将它们相互比较，还与前一篇论文中参照我们之前的研究定义的III.1类细胞的实例进行了比较。采用计算机辅助的树突三维重建以及对一对树突重叠的ON DS和ON-OFF DS神经节细胞进行分析的研究表明，这两种类型的DS神经节细胞在b亚层中部（第4层）部分共同分层。一些ON DS神经节细胞的少数树突延伸至a亚层的报道得到了证实。对树突重叠的ON-OFF DS神经节细胞和星爆无长突细胞对的研究揭示了这两种细胞类型的精确共同分层，以及在内网状层（IPL）的两个亚层中，星爆终扣与ON-OFF DS神经节细胞树突紧密并置的许多点。高分辨率光学显微镜和电子显微镜证实了这一点。因此，可以得出结论，当ON DS神经节细胞偶尔有树突上升到该水平时，它们也部分与b型星爆（胆碱能）无长突细胞共同分层，显然也部分与a型星爆无长突细胞共同分层。两种DS神经节细胞的共同分层与包括一些视锥双极细胞输入在内的一些共同输入的共享一致。它们与星爆无长突细胞的共同分层与胆碱能激动剂对ON和ON-OFF DS神经节细胞强大药理作用的生理学证明相符。双分层的ON-OFF DS神经节细胞和通常单分层的ON DS神经节细胞在树突分层上的主要差异与IPL中ON和OFF通路的双亚层组织一致。从OFF反应阈值的角度讨论了ON DS细胞在a亚层中偶尔出现分支的问题。（摘要截选至400字）
