Ahnelt P, Kolb H
Department of General and Comparative Physiology, University of Vienna, Austria.
J Comp Neurol. 1994 May 15;343(3):387-405. doi: 10.1002/cne.903430305.
The relationship of primate horizontal cells (HC) to cone pedicles was assessed by superimposing the cone inner segment mosaic upon Golgi-impregnated HC dendritic terminal clusters in a light microscope (LM) study. The HI, HII, and HIII types of HC were identified, hand-drawn, photographed, and analyzed by computer graphics methods. Blue cone (B-cones) inner segments and their projected pedicles were distinguished from red (R-cones) and green (G-cones) cones on morphological criteria. Thus the inclusion or avoidance of B-cone pedicles by the various HC types' dendritic terminal clusters establishes whether there is any color specificity to their connections. In addition, we made counts of the number of dendritic terminals in the clusters going to cone pedicles in the various HCs' dendritic fields and plotted these against distances the cone pedicles lay from the cell body. In this way we could evaluate the weighting of spectral type of cone input. In general, the three HC types made the majority of their dendritic contacts with cones lying closest to their cell bodies at the center of their dendritic fields. However, HI and HIII cells, with their distinct terminal clusters, did not contact all the centrally located cones uniformly. They either avoided completely (HIII cells) or made only sparse dendritic connections (HI cells) with certain cones. The avoided or sparsely innervated cones were identified as B-cones. HII cells, on the other hand, with their more profuse and diffusely branched dendrites, appeared to contact all overlying cone pedicles and, in contrast to HI and HIII cells, directed a relatively larger number of dendrites to B-cone positions. Axon terminals of HII cells appeared to contact B-cones exclusively.
在一项光学显微镜（LM）研究中，通过将视锥细胞内节镶嵌图叠加在高尔基染色的水平细胞（HC）树突末梢簇上，评估了灵长类动物水平细胞与视锥小足的关系。识别出HI、HII和HIII型水平细胞，手绘、拍照，并通过计算机图形学方法进行分析。根据形态学标准，将蓝视锥细胞（B-视锥细胞）内节及其投射的小足与红（R-视锥细胞）和绿（G-视锥细胞）视锥细胞区分开来。因此，各种水平细胞类型的树突末梢簇对B-视锥小足的包含或回避，确定了它们的连接是否存在颜色特异性。此外，我们对不同水平细胞树突野中与视锥小足相连的树突末梢数量进行了计数，并将这些数量与视锥小足到细胞体的距离进行了绘图。通过这种方式，我们可以评估视锥细胞输入的光谱类型权重。一般来说，这三种水平细胞类型的大多数树突接触位于其树突野中心最靠近其细胞体的视锥细胞。然而，具有独特末梢簇的HI和HIII细胞，并未均匀地接触所有位于中心的视锥细胞。它们要么完全回避（HIII细胞），要么仅与某些视锥细胞形成稀疏的树突连接（HI细胞）。被回避或神经支配稀疏的视锥细胞被确定为B-视锥细胞。另一方面，HII细胞具有更丰富且分支分散的树突，似乎接触所有覆盖的视锥小足，并且与HI和HIII细胞不同，它们将相对较多的树突导向B-视锥细胞位置。HII细胞的轴突末梢似乎仅与B-视锥细胞接触。
