“Extra” optic fibers exclude normal fibers from tectal regions in goldfish
“Extra” optic fibers exclude normal fibers from tectal regions in goldfish
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“额外”光纤排除了金鱼顶盖区域的正常纤维
DOI：
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发表时间：
1979
期刊：
影响因子：
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通讯作者：
R. Meyer
中科院分区：
文献类型：
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作者：
R. Meyer
一小群选定的光纤通过手术从一个顶盖偏转到另一个顶盖，从而创造了一个来自同侧视网膜小区域的新的额外投射。这个“受体”顶盖的正常纤维也被切断，因此偏转的纤维和正常的纤维几乎在同一时间重新进入这个顶盖。用放射自显影和电生理标测分析神经再支配模式。这两种技术都表明，偏转的纤维和“正常”的纤维无法混合。偏转的纤维通常在失神经受者顶盖的适当区域形成几个明确的神经支配斑块。正常纤维填充在剩余的无神经支配的顶盖区域，并完全或几乎完全排除在偏转纤维占据的斑块之外。这种分离往往相当尖锐，明显的平均重叠小于25-50μm。电生理表明，偏转和正常纤维的投射都是视网膜组织的，但正常纤维的投射是压缩的。这种压缩是被挤压到比正常范围更小的顶盖区域的明显后果，类似于先前观察到的顶盖部分被切除后的情况。然而，本实验中可忽略的外科损伤排除了先前提出的产生压迫的那种细胞化学重组。这些发现也为光纤之间的竞争性相互作用提供了证据。
A small group of selected optic fibers were surgically deflected from one tectum into the other, thus creating a novel additional projection originating from a small area of ipsilateral retina. The normal fibers to this “recipient” tectum were also severed so that both the deflected and the normal fibers regrew into this tectum at about the same time. The reinnervation pattern was analyzed by autoradiography and electrophysiologic mapping. Both techniques showed that the deflected fibers and the “normal” fibers failed to intermix. The deflected fibers typically formed several well‐defined patches of innervation in roughly the appropriate region of denervated recipient tectum. The normal fibers filled in the remaining uninnervated tectal areas and were completely or nearly completely excluded from the patches occupied by the deflected fibers. This segregation was often quite sharp having an apparent average overlap less than 25–50 μm. The electrophysiology indicated that the projections of both deflected and normal fibers were retinotopically organized but that the mapping by the normal fibers was compressed. This compression, an apparent consequence of being squeezed onto a smaller than normal region of tectum, was similar to that previously observed following ablations of part of the tectum. The negligible surgical damage in the present experiment, however, excludes the kind of cytochemical reorganization previously suggested to produce compression. The findings also provide evidence for a competitive type of interaction between optic fibers.