PRENATAL AND POSTNATAL-DEVELOPMENT OF RETINOGENICULATE AND RETINOCOLLICULAR PROJECTIONS IN THE MOUSE
PRENATAL AND POSTNATAL-DEVELOPMENT OF RETINOGENICULATE AND RETINOCOLLICULAR PROJECTIONS IN THE MOUSE
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DOI：
10.1002/cne.902300406
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发表时间：
1984-01-01
影响因子：
2.5
通讯作者：
IMBERT, M
中科院分区：
文献类型：
--
作者：
GODEMENT, P;SALAUN, J;IMBERT, M
用氚标记的脯氨酸和辣根过氧化物酶（HRP）的顺行转运研究了C57 BL/6系小鼠胚胎和新生期视网膜向外侧膝状体背核（dLGN）和上级丘（SC）投射的发育。E16时，同侧纤维仅限于近端视束;它们向dLGN和SC的生长延迟至E18-birth。在出生后的前2天，早期同侧纤维群侵入dLGN。这些纤维中的大多数生长在dLGN的中背区中或周围，即，未来的双目部分。纤维也存在，但密度较低，在腹侧一半的核，此后变得分散或丢失，没有在任何阶段变得密集。一些密度更高的标记也存在于同侧的外边缘的dLGN，就在下面的视束，后来消失。在出生后第三天，同侧的纤维建立一个深和密度更高的投影沿内侧和背侧边界的dLGN;这个投影重叠的交叉投影的一部分，在这个年龄延伸到整个核。每个投射的分离开始于出生后第四天，此时交叉纤维开始从非交叉投射的小区域消失。这个过程又持续了4天。在此期间，同侧纤维从dLGN的最深层退出，其终末密度逐渐增加，到出生后第8天，两种投射已经很好地分离，密集的交叉投射首先出现在出生时的SC表面附近。在此之前，视网膜纤维遍布丘板和软脑膜下方的神经元，未交叉的纤维在出生和P3之间侵入SC。它们优先位于SC的前部和内侧。随后，这些投影的层流和切线范围发生减少，同时加强同侧输入到几个小的，纵向取向的集群位于交叉投影的深处。
The development of retinal projections to the dorsal lateral geniculate nucleus (dLGN) and superior colliculus (SC) has been studied in fetal and neonatal mice of the pigmented C57BL/6 strain, using the anterograde transport of tritiated proline and horseradish peroxidase (HRP).Retinal efferents are present contralaterally just beyond the chiasm at E14. By E16 they have grown into both dLGN and SC. Ipsilateral fibers are limited to the proximal optic tract at E16; their growth into dLGN and SC is delayed until E18‐birth.During the first 2 postnatal days, an early population of ipsilateral fibers invades the dLGN. Most of these fibers grow in or around the mediodorsal sector of the dLGN, i.e., the future binocular segment. Fibers are also present, but at lower densities, in the ventral half of the nucleus and thereafter become dispersed or are lost, without at any stage becoming dense. Some denser labeling is also present ipsilaterally in the outer rim of dLGN, just below the optic tract, and later disappears.On the third postnatal day, the ipsilateral fibers establish a deep and denser projection along the medial and dorsal borders of dLGN; this projection overlaps part of the crossed projection, which at this age extends to the whole nucleus. The segregation of each projection starts on the fourth postnatal day, when crossed fibers begin to disappear from the small region of uncrossed projection. This process goes on for another 4 days. During this period, the ipsilateral fibers withdraw from the deepest layer of dLGN, and their terminal density increases gradually; by the eighth postnatal day, both projections are already well separated.Dense crossed projections first appear near the surface of the SC at birth. Prior to this, retinal fibers course throughout neurons of the collicular plate and underneath the pia.The uncrossed fibers invade the SC between birth and P3. They are located preferentially in the anterior and medial aspect of the SC. Subsequently, there occurs a diminution in the laminar and tangential extent of these projections, simultaneously with an intensification of the ipsilateral input to several small, longitudinally oriented clusters located deep to the crossed projections.