Carpenter M B, Nakano K, Kim R
J Comp Neurol. 1976 Feb 15;165(4):401-15. doi: 10.1002/cne.901650402.
In spite of repeated demonstrations by degeneration technics, nigrothalamic fibers have been regarded with some skepticism. Attempts were made to trace nigral efferent projections in the monkey by autoradiographic technics. Tritiated amino acids (L-leucine, L-lysine and L-proline), injected into portions of the substantia nigra (SN), labeled cells in four regions, designated as, (1) rostrolateral, (2) caudolateral, (3) rostromedial and (4) central. Rostrolateral nigral neurons transported radioactive label preferentially and abundantly to thalamic nuclei; localized isotope was found in parts of three thalamic nuclei, the medial part of the ventral lateral nucleus (VLm), the magnocellular part of the ventral anterior nucleus (VAmc), and the paralaminar part of the dorsomedial nucleus (DMpl)9 Lateral neurons in the caudal half of the SN transmitted radioactive label to the same thalamic nuclei as rostrolateral nigral neuron. Isotope transported to portions of the striatum was modest and localized. Radioactive label taken up by large cells in the caudal third of the SN was transported to portions of the striatum, but not to thalamic nuclei. Labeled nigral neurons in the medial two-thirds of the rostral half of the SN, and in the middle third of the central part of the SN, transported the label mainly to parts of the caudate nucleus and putamen. In these animals modest radioactive label was seen in VLm and VAmc, but not in other thalamic nuclei. There was no evidence that nigral neurons project to the subthalamic nucleus. No radioactive transport from nigral neurons was detected in the superior colliculus, the midbrain tegmentum, or the red nucleus, and none was transported to more caudal brain stem nuclei. Nigrothalamic fibers arise particularly from cells in rostral and lateral parts of the substantia nigra. While some cells in other parts of the nigra project to thalamic nuclei, these appear scattered and less numerous. Large cells in caudal parts of the SN do not project to thalamic nuclei. These observations confirm nigrothalamic projections to VLm and VAmc, and identify a new nigral projection to part of the dorsomedial nucleus of the thalamus (DMpl). No nigral efferent fibers project to any of the intralaminar thalamic nuclei.
尽管采用变性技术进行了多次论证，但黑质丘脑纤维仍受到一定程度的怀疑。曾尝试通过放射自显影技术追踪猴子的黑质传出投射。将氚标记的氨基酸（L-亮氨酸、L-赖氨酸和L-脯氨酸）注入黑质（SN）的不同部位，标记了四个区域的细胞，分别为：（1）嘴外侧区，（2）尾外侧区，（3）嘴内侧区和（4）中央区。嘴外侧黑质神经元优先且大量地将放射性标记物转运至丘脑核团；在三个丘脑核团的部分区域发现了定位的同位素，即腹外侧核内侧部（VLm）、腹前核大细胞部（VAmc）和背内侧核旁层部（DMpl）。SN尾侧半的外侧神经元将放射性标记物传递至与嘴外侧黑质神经元相同的丘脑核团。转运至纹状体部分区域的同位素数量适中且分布局限。SN尾侧三分之一的大细胞摄取的放射性标记物被转运至纹状体部分区域，但未转运至丘脑核团。SN嘴侧半内侧三分之二以及SN中央部中间三分之一的标记黑质神经元，主要将标记物转运至尾状核和壳核的部分区域。在这些动物中，VLm和VAmc可见适度的放射性标记，但在其他丘脑核团未见。没有证据表明黑质神经元投射至底丘脑核。在中脑上丘、中脑被盖或红核中未检测到黑质神经元的放射性转运，也没有转运至更靠尾侧的脑干核团。黑质丘脑纤维尤其起源于黑质嘴侧和外侧部分的细胞。虽然黑质其他部分的一些细胞投射至丘脑核团，但这些细胞显得分散且数量较少。SN尾侧部分的大细胞不投射至丘脑核团。这些观察结果证实了黑质丘脑向VLm和VAmc的投射，并确定了黑质向丘脑背内侧核部分区域（DMpl）的新投射。没有黑质传出纤维投射至任何丘脑板内核团。
