CHOLINERGIC PROJECTIONS FROM THE MIDBRAIN RETICULAR-FORMATION AND THE PARABIGEMINAL NUCLEUS TO THE LATERAL GENICULATE-NUCLEUS IN THE TREE SHREW
CHOLINERGIC PROJECTIONS FROM THE MIDBRAIN RETICULAR-FORMATION AND THE PARABIGEMINAL NUCLEUS TO THE LATERAL GENICULATE-NUCLEUS IN THE TREE SHREW
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DOI：
10.1002/cne.902720105
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发表时间：
1988-06-01
影响因子：
2.5
通讯作者：
DIAMOND, IT
中科院分区：
文献类型：
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作者：
FITZPATRICK, D;CONLEY, M;DIAMOND, IT
利用胆碱乙酰转移酶（ChAT）的免疫细胞化学定位，研究了树鼩外侧膝状核（GL）内胆碱能纤维的分布和来源。chat免疫反应纤维遍布整个丘脑，但与其他主要感觉丘脑核（内侧膝状核，腹侧后核）相比，GL中尤其丰富。单个chat免疫反应纤维的直径非常细，沿其长度显示许多小肿胀。在GL内，chat免疫反应纤维在层间区比层间区更多，在大多数情况下，密度最大的是在第4层和第5层。GL中chat -免疫反应纤维的两个来源已被确定，分别是双侧旁核（Pbg）和桥脚被盖核（PPT）。结合免疫细胞化学、轴突转运和病变方法，确定每种对GL中chat -免疫反应纤维分布的贡献。来自Pbg的投影是严格对侧的，穿过视束，终止于第1、3、5和6层以及第5层两侧的层间区。PPT的投影是双侧的（同侧占优势），并终止于整个GL以及其他丘脑核。病变的Pbg消除ChAT-immunoreactive纤维通常发现视神经束但ChAT-immunoreactive纤维的密度没有明显影响侧GL。相比之下,病变的PPT产生的数量明显减少ChAT-immunoreactive纤维GL和其他的一侧丘脑核病变但没有明显影响的数量ChAT-immunoreactive视神经束纤维。这些结果表明，有两个来源的胆碱能投射到GL在树鼩可能发挥不同的作用，在调节视觉活动的传输到皮层。Pbg被认为是视觉系统的一部分，因为它与上丘的浅层相互连接，而PPT是中脑网状结构的一部分，被认为在调节整个丘脑和脑干其他区域的神经元活动方面起着非模态特异性的作用。
The distribution and sources of putative cholinergic fibers within the lateral geniculate nucleus (GL) of the tree shrew have been examined by using the immunocytochemical localization of choline acetyltransferase (ChAT). ChAT-immunoreactive fibers are found throughout the thalamus but are particularly abundant in the GL as comapred to other principal sensory thalamic nuclei (medial geniculate nucleus, ventral posterior nucleus). Individual ChAT-immunoreactive fibers are extremely fine in caliber and display numerous small swellings along their lengths. Within the GL, ChAT-immunoreactive fibers are more numerous in the layers than in the interlaminar zones and, in most cases, the greatest density is found in layers 4 and 5. Two sources for the ChAT-immunoreactive fibers in the GL have been identified.sbd.the parabigeminal nucleus (Pbg) and the pedunculopontine tegmental nucleus (PPT).sbd.and the contribution that each makes to the distribution of ChAT-immunoreactive fibers in GL was determined by combining immunocytochemical, axonal transport, and lesion methods. The projection from the Pbg is strictly contralateral, travels via the optic tract, and terminates in layers 1, 3, 5, and 6 as well as the interlaminar zones on either side of layer 5. The projection from PPT is bilateral (ipsilateral dominant) and terminates throughout the GL as well as in other thalamic nuclei. Lesions of the Pbg eliminate the ChAT-immunoreactive fibers normally found in the optic tract but have no obvious effect on the density of ChAT-immunoreactive fibers in the contralateral GL. In contrast, lesions of PPT produce a conspicuous decrease in the number of ChAT-immunoreactive fibers in the GL and in other thalamic nuclei on the side of the lesion but have no obvious effect on the number of ChAT-immunoreactive fibers in the optic tract. These results suggest that there are two sources of cholinergic projections to the GL in the tree shrew which are likely to play different roles in modulating the transmission of visual activity to the cortex. The Pbg is recognized as a part of the visual system by virtue of its reciprocal connections with the superficial layers of the superiro colliculus, while the PPT is a part of the midbrain reticular formation and is thought to play a non-modality-specific role in modulating the activity of neurons throughout the thalamus and in other regions of the brainstem.