Smith Y, Hazrati L N, Parent A
Centre de recherche en neurobiologie, Université Laval, Québec, Canada.
J Comp Neurol. 1990 Apr 8;294(2):306-23. doi: 10.1002/cne.902940213.
The organization of the efferent connections of the subthalamic nucleus was studied in the squirrel monkey (Saimiri sciureus) by using the lectin Phaseolus vulgaris-leucoagglutinin (PHA-L) as an anterograde tracer. At the level of the basal forebrain, anterogradely labeled fibers and axon terminals were mostly found in the striatopallidal complex and the substantia innominata. In cases in which the PHA-L injection sites were placed in the central or the lateral third of the subthalamic nucleus, numerous anterogradely labeled fibers were seen to arise from the injection loci and innervate massively the globus pallidus. At pallidal levels the fibers formed bands lying parallel and adjacent to the medullary laminae. The number and the complexity of the topographical organization of these bands varied with the size and the location of the PHA-L injection site. When examined at a higher magnification, the bands of subthalamopallidal fibers appeared as rich plexuses of short axon collaterals with small bulbous enlargements that closely surrounded the cell bodies and primary dendrites of pallidal cells. In contrast, PHA-L injection involving the medial tip of the subthalamic nucleus did not produce bandlike fiber patterns in the globus pallidus. Instead, the labeled fibers formed a diffuse plexus occupying the ventral part of the rostral pole of the globus pallidus as well as the subcommissural pallidal region. The substantia innominata contained a moderate number of labeled fibers and axon terminals following injection of PHA-L in the medial tip of the subthalamic nucleus. A small to moderate number of anterogradely labeled fibers were seen in the putamen after all PHA-L injections. These subthalamostriatal fibers were long, linear, and branched infrequently. At midbrain level the substantia nigra contained a significant number of anterogradely labeled fibers and axon terminals following PHA-L injection in the subthalamic nucleus. The subthalamonigral fibers descended along the ventromedial part of the cerebral peduncle and swept laterally to reach their target. Most of these fibers formed small plexuses along the base of the pars reticulata, whereas a few others ascended along the cell columns of the pars compacta that impinged deeply within the pars reticulata. More caudally in the brainstem, a small number of fibers occurred in the area of the pedunculopontine nucleus and in the periaqueductal gray. These findings indicate that besides its well-known connection with the pallidum, the subthalamic nucleus gives rise to widespread projections to other components of the basal ganglia in primates.
通过使用凝集素菜豆白细胞凝集素（PHA-L）作为顺行示踪剂，在松鼠猴（Saimiri sciureus）中研究了丘脑底核传出连接的组织。在基底前脑水平，顺行标记的纤维和轴突终末主要见于纹状体苍白球复合体和无名质。当PHA-L注射部位位于丘脑底核的中央或外侧三分之一时，可见大量顺行标记的纤维从注射部位发出并大量支配苍白球。在苍白球水平，纤维形成与髓板平行且相邻的带。这些带的拓扑组织的数量和复杂性随PHA-L注射部位的大小和位置而变化。在更高放大倍数下观察时，丘脑底核-苍白球纤维带表现为丰富的短轴突侧支丛，带有小的球茎状膨大，紧密围绕苍白球细胞的胞体和初级树突。相反，涉及丘脑底核内侧尖端的PHA-L注射在苍白球中未产生带状纤维模式。取而代之的是，标记的纤维形成一个弥漫性丛，占据苍白球嘴侧极的腹侧部分以及连合下苍白球区域。在丘脑底核内侧尖端注射PHA-L后，无名质含有适量的标记纤维和轴突终末。在所有PHA-L注射后，壳核中可见少量至适量的顺行标记纤维。这些丘脑底核-纹状体纤维长而呈线性，分支较少。在中脑水平，在丘脑底核注射PHA-L后，黑质含有大量顺行标记的纤维和轴突终末。丘脑底核-黑质纤维沿大脑脚的腹内侧部分下行并横向延伸以到达其靶标。这些纤维大多数沿网状部底部形成小丛，而其他一些则沿致密部的细胞柱上升，深入网状部。在脑干更靠尾侧的部位，脚桥核区域和导水管周围灰质中有少量纤维。这些发现表明，除了与苍白球的众所周知的连接外，丘脑底核还向灵长类动物基底神经节的其他成分发出广泛的投射。
