Hayes B P, Holden A L
Exp Brain Res. 1983;49(2):189-97. doi: 10.1007/BF00238579.
The terminals of the centrifugal fibres of the pigeon retina have been labelled by anterograde axonal transport or diffusion of horseradish peroxidase, and their distribution studied in whole amounts of the retina. Centrifugal terminal arborisations are concentrated in a band near the projection of the horizontal meridian on the retina. Within this band there are high density areas next to the area centralis and in the mid-temporal retina. The arborisations are largely absent from the red field and are nearly randomly arrayed. Their distribution resembles that of the displaced ganglion cells but not of other retinal neurons. We estimate that approximately 7,000 centrifugal terminal arborisations are present in each retina. Approximately two-thirds of these are convergent, with branches ending in large terminals clustered around a single cell in the amacrine sublayer; often penetrating up to 10 microns into the inner nuclear layer. The remainder are divergent endings which innervate a larger area of retina with widely spaced small terminals about 1 micron in diameter. Possible synaptic contacts between centrifugal terminals and displaced ganglion cells are occasionally seen; these contacts and the similarity in distribution suggest a link between the centrifugal and accessory optic systems.
鸽子视网膜离心纤维的终末已通过辣根过氧化物酶的顺行轴突运输或扩散进行标记，并在整个视网膜中研究了它们的分布。离心终末分支集中在视网膜上水平子午线投影附近的一条带内。在这条带内，中央凹区域旁边和颞侧视网膜中部有高密度区域。红色区域基本没有分支，且分支排列几乎是随机的。它们的分布类似于移位神经节细胞的分布，而与其他视网膜神经元不同。我们估计每个视网膜中大约存在7000个离心终末分支。其中约三分之二是会聚性的，其分支在无长突细胞亚层中围绕单个细胞聚集形成大终末；常常向内核层深入达10微米。其余的是发散性终末，它们通过直径约1微米、间距较大的小终末支配视网膜的更大区域。偶尔可见离心终末与移位神经节细胞之间可能的突触联系；这些联系以及分布上的相似性表明离心视觉系统和副视系统之间存在联系。
