Taylor J S, Gaze R M
J Embryol Exp Morphol. 1985 Oct;89:383-401.
The paths taken by fibres regenerating to the tectum from various parts of the Xenopus retina were investigated in whole-mount preparations, after localized retinal labelling with HRP. The effects of different environments on the fibres were studied by comparing contralateral with ipsilateral regeneration, in the presence of the other eye or after it had been removed in embryonic life. Under all conditions fibres from the various parts of the retina regenerated to the corresponding appropriate parts of the tectum, but they took a variety of pathways, some grossly abnormal, to get there. Contralaterally regenerating fibres tended to behave less abnormally than ipsilateral fibres; and regeneration in the absence of the other eye tended to be more abnormal than in its presence. In any one category of regeneration the most nearly normal pathways were those of fibres from temporal retina, followed by ventral, nasal and dorsal fibres. Fibres regenerating from all parts of the retina, in the presence of the other eye, tended to become gathered into the medial brachium as they approached the tectum. All regenerating fibres approached their tectal terminations by one or more of three main pathways: round one or both brachia, thus encircling the tectum to get to their terminal zone; directly across the tectum; or by passing on to the tectum before changing course. The changes of direction required to enable fibres wrongly positioned in the tract to reach their correct terminal zones were frequently sudden and considerable, and took place on the tectum or at the tectodiencephalic junction. The results are discussed in relation to the differing substrates over which the fibres regenerate.
在用辣根过氧化物酶（HRP）对非洲爪蟾视网膜进行局部标记后，通过整装标本研究了从非洲爪蟾视网膜各部位再生至顶盖的纤维所采取的路径。通过比较在另一只眼存在或在胚胎期将其摘除的情况下对侧与同侧再生，研究了不同环境对纤维的影响。在所有条件下，来自视网膜各部位的纤维都再生至顶盖的相应合适部位，但它们通过多种路径到达那里，有些路径非常异常。对侧再生的纤维往往比同侧纤维表现得异常程度低；在没有另一只眼的情况下再生往往比有另一只眼时更异常。在任何一类再生中，最接近正常的路径是来自颞侧视网膜的纤维，其次是腹侧、鼻侧和背侧纤维。在另一只眼存在的情况下，从视网膜各部位再生的纤维在接近顶盖时往往会聚集到内侧臂。所有再生纤维通过以下三种主要路径中的一种或多种接近它们在顶盖的终末：绕过一个或两个臂，从而环绕顶盖到达它们的终末区；直接穿过顶盖；或在改变方向之前传递到顶盖上。使在束中位置错误的纤维到达其正确终末区所需的方向变化通常是突然且显著的，并且发生在顶盖或顶盖间脑交界处。结合纤维再生所经过的不同基质对结果进行了讨论。
