Sugita S, Otani K, Tokunaga A, Terasawa K
Exp Brain Res. 1985;60(3):564-75. doi: 10.1007/BF00236943.
Tecto-thalamic projections in the hereditary bilaterally microphthalmic rat were studied by means of WGA-HRP injection into the dorsal lateral geniculate nucleus (LGNd) and the lateroposterior thalamic nucleus (LP). Histological study in the mutant rats showed that whereas LGNd and superficial layers of the superior colliculus (SC) suffered from a remarkable reduction in size, LP had no histological changes as compared to the normal animals. Unilateral injection of the tracer into the microphthalmic LGNd showed that WGA-HRP positive neurons were present mostly in the ipsilateral str. griseum superficiale (SGS) of the SC. However, the number of labeled SGS neurons of the microphthalmic animals was about 3% of the normal. Although cell bodies of the normal tecto-LGNd neurons in the SGS were spindle-form in shape and issued one or two proximal dendrites from each pole, the microphthalmic tecto-LGNd neurons showed an irregular contour and their dendrites were not so intensively labeled. Unilateral injections of WGA-HRP into the LP revealed that the tecto-LP neurons were mainly distributed in the ipsilateral str. opticum of the colliculus (SO) in both normal and microphthalmic animals. However, the number of labeled SO cells in the microphthalmic rat was about one-half of the normal. Furthermore, the size of labeled tecto-LP neurons was smaller than that of the normal ones, and they showed irregular round to oval cell bodies with equivocally labeled dendrites, in contrast to the normal tecto-LP neurons with polygonal cell bodies extending three or more dendrites in a radial fashion. These results indicate that there exist the tecto-LGNd and -LP projection neurons in the microphthalmic rat and that their laminally segregated projection is fundamentally preserved. However, the number of the tecto-thalamic projection neurons, especially of the tecto-LGNd cells, was markedly diminished in the mutant tectum compared to normals.
通过将WGA-HRP注入背外侧膝状核（LGNd）和丘脑后外侧核（LP），研究了遗传性双侧小眼大鼠的顶盖-丘脑投射。对突变大鼠的组织学研究表明，LGNd和上丘（SC）的表层尺寸显著减小，而与正常动物相比，LP没有组织学变化。将示踪剂单侧注入小眼LGNd表明，WGA-HRP阳性神经元主要存在于SC同侧的浅灰质层（SGS）。然而，小眼动物标记的SGS神经元数量约为正常动物的3%。虽然正常情况下SGS中顶盖-LGNd神经元的细胞体呈纺锤形，每个极发出一两个近端树突，但小眼顶盖-LGNd神经元的轮廓不规则，其树突标记不那么密集。将WGA-HRP单侧注入LP显示，在正常和小眼动物中，顶盖-LP神经元主要分布在丘脑中的同侧视层（SO）。然而，小眼大鼠中标记的SO细胞数量约为正常大鼠的一半。此外，标记的顶盖-LP神经元的大小比正常神经元小，它们的细胞体呈不规则圆形至椭圆形，树突标记不明显，而正常的顶盖-LP神经元的细胞体呈多边形，以放射状延伸三个或更多树突。这些结果表明，小眼大鼠中存在顶盖-LGNd和-LP投射神经元，并且它们分层分离的投射基本得以保留。然而，与正常大鼠相比，突变顶盖中顶盖-丘脑投射神经元的数量，尤其是顶盖-LGNd细胞的数量明显减少。
