Ephrin-As are required for the topographic mapping but not laminar choice of physiologically distinct RGC types.
Ephrin-As are required for the topographic mapping but not laminar choice of physiologically distinct RGC types.
复制标题
地形图绘制需要 Ephrin-As，但不需要生理上不同的 RGC 类型的层层选择。
DOI：
10.1002/dneu.22265
复制
发表时间：
2015
影响因子：
3
通讯作者：
Feldheim,DavidA
中科院分区：
文献类型：
--
作者：
Sweeney,NealT;James,KielyN;Sales,EmilyC;Feldheim,DavidA
在视网膜丘投影中，来自功能不同的视网膜神经节细胞（RGC）类型的轴突沿上丘（SC）的浅至深轴以刻板的方式形成突触。每个层都包含一个有序的视觉场景地形图，但不同的层接收来自不同的rgc组的输入，并且每个层的输入与其他层对齐以整合并行的视觉信息流。为了确定层流组织与生理上定义的RGC类型的地形之间的关系，我们在野生型和ephrin‐A突变小鼠中使用了遗传和解剖轴突追踪技术。我们发现相邻的相同生理类型的rgc可以将轴突发送到异位和正常的地形位置，这支持了一个独立于ephrin‐a的定位线索的外显子模型。虽然在ephrin‐A2/A5双突变小鼠中SC的整体层流组织不受影响，但对异位终止的层流位置的分析表明，不同类型的RGC的地形图是不一致的。这些数据支持了一种假设，即视网膜视丘投影是许多单独的二维地形图的叠加，这些地形图起源于特定类型的rgc，需要ephrin - a信号传导，并且独立于其他地形图形成。©2015 Wiley期刊公司中国生物医学工程学报（英文版），2015
In the retinocollicular projection, the axons from functionally distinct retinal ganglion cell (RGC) types form synapses in a stereotypical manner along the superficial to deep axis of the superior colliculus (SC). Each lamina contains an orderly topographic map of the visual scene but different laminae receive inputs from distinct sets of RGCs, and inputs to each lamina are aligned with the others to integrate parallel streams of visual information. To determine the relationship between laminar organization and topography of physiologically defined RGC types, we used genetic and anatomical axon tracing techniques in wild type and ephrin‐A mutant mice. We find that adjacent RGCs of the same physiological type can send axons to both ectopic and normal topographic locations, supporting a penetrance model for ephrin‐A independent mapping cues. While the overall laminar organization in the SC is unaffected in ephrin‐A2/A5 double mutant mice, analysis of the laminar locations of ectopic terminations shows that the topographic maps of different RGC types are misaligned. These data lend support to the hypothesis that the retinocollicular projection is a superimposition of a number of individual two‐dimensional topographic maps that originate from specific types of RGCs, require ephrin‐A signaling, and form independently of the other maps. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 584–593, 2015