Sakai S T, Inase M, Tanji J
Department of Anatomy, Colleges of Medicine, Michigan State University, East Lansing 48824, USA.
J Comp Neurol. 1996 Apr 29;368(2):215-28. doi: 10.1002/(SICI)1096-9861(19960429)368:2<215::AID-CNE4>3.0.CO;2-6.
To address the question of segregated projections from the internal segment of the globus pallidus (GPi) and the cerebellar nuclei (Cb) to the thalamus in the monkey, we employed a double anterograde labeling strategy combining the anterograde transport of horseradish peroxidase conjugated to wheat germ agglutinin (WGA-HRP) with biotinylated dextran amine (BDA) transport. The tissue was processed sequentially for WGA-HRP, and then BDA immunohistochemistry using two different chromogens. Since the two labels were easily distinguishable on the same histological section, the interrelationship between the cerebellar and pallidal projection systems could be directly evaluated. We found that both the cerebellothalamic and pallidothalamic label consisted of dense plexuses of labeled fibers and swellings in a patch-like configuration. The patches or foci of labeling were distributed either as dense single label or as interdigitating patches of double label. We found dense single label in the central portion of the ventral anterior nucleus pars principalis (VApc) and the ventral lateral nucleus pars oralis (VLo) following the GPi injections or in the central portion of the ventral posterior lateral nucleus pars oralis (VPLo) and nucleus X (X) following the cerebellar nuclei injections. Complementary interdigitating patches of WGA-HRP and BDA labeling were found primarily in transitional border regions between thalamic nuclei. On occasion, we found overlap of both labels. We observed a gradient pattern in the density of the pallidothalamic and cerebellothalamic projections. The pallidothalamic territory included VApc, VLo, and the ventral lateral nucleus pars caudalis (VLc), with the density of these projections decreasing along an anterior to posterior gradient in the thalamus. Occasional patches of pallidal label were found in VPLo and nucleus X. Conversely, the density of cerebellothalamic projections increased along the same gradient, with the cerebellothalamic territory extending anteriorly beyond the cell-sparse zones of VPLo, X, and VLc to include VLo and VApc also. These data suggest that although the cerebellar and pallidal projections primarily occupy separate thalamic territories, individual thalamic nuclei receive differentially weighted inputs from these sources.
为了探讨猴脑内苍白球内侧部（GPi）和小脑核（Cb）向丘脑的分离投射问题，我们采用了双重顺行标记策略，即将与小麦胚凝集素结合的辣根过氧化物酶（WGA-HRP）的顺行运输与生物素化葡聚糖胺（BDA）运输相结合。对组织依次进行WGA-HRP处理，然后使用两种不同的显色剂进行BDA免疫组织化学。由于在同一组织切片上这两种标记很容易区分，因此可以直接评估小脑和苍白球投射系统之间的相互关系。我们发现，小脑丘脑和苍白球丘脑标记均由标记纤维的密集丛和呈斑块状分布的肿胀组成。标记的斑块或灶点以密集的单一标记形式分布，或以双标记的相互交错斑块形式分布。在注射GPi后，我们在腹前核主部（VApc）和腹外侧核口部（VLo）的中央部分发现了密集的单一标记；在注射小脑核后，在腹后外侧核口部（VPLo）和X核的中央部分发现了密集的单一标记。WGA-HRP和BDA标记的互补性相互交错斑块主要出现在丘脑核之间的过渡边界区域。偶尔，我们发现两种标记有重叠。我们观察到苍白球丘脑和小脑丘脑投射密度存在梯度模式。苍白球丘脑区域包括VApc、VLo和腹外侧核尾部（VLc），这些投射的密度在丘脑中沿前后梯度降低。在VPLo和X核中偶尔发现苍白球标记斑块。相反，小脑丘脑投射的密度沿相同梯度增加，小脑丘脑区域向前延伸至VPLo、X和VLc的细胞稀疏区之外，也包括VLo和VApc。这些数据表明，尽管小脑和苍白球投射主要占据不同的丘脑区域，但单个丘脑核从这些来源接收的输入权重不同。
