Structure-function relationships in the primate superior colliculus. I. Morphological classification of efferent neurons.
Structure-function relationships in the primate superior colliculus. I. Morphological classification of efferent neurons.
复制标题
灵长类动物上丘的结构与功能关系。
DOI：
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发表时间：
1988
影响因子：
2.5
通讯作者：
S. Highstein
中科院分区：
文献类型：
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作者：
A. Moschovakis;A. Karabelas;S. Highstein
1. 用辣根过氧化物酶（HRP）对麻醉麻痹的松鼠猴上丘（SC）神经元进行细胞内注射，建立其顶端输出神经元的形态学分类。这些神经元在刺激对侧背前束（SC）后产生的反向反应在生理学上被识别出来。这些细胞也以突触后电位对同侧黑质、脑蒂和对侧顶盖的刺激做出反应。2. 对27个恢复细胞的体突轮廓和轴突轨迹进行定量光镜分析发现，顶叶传出神经元主要有L （n = 7）、X （n = 8）和T （n = 12）三组。3. L神经元是小型或中等大小的细胞，具有相对复杂的树突树，主要位于SC的浅层。它们参与同侧下行和背侧上行构造束。L轴突的内在侧支在母细胞体附近和更腹侧的较深的顶层内部署大量钮扣。4. X神经元大多体积大，形状多极，树突树相对复杂。它们的细胞体主要位于灰质中层，偶尔也位于视层。X神经元的轴突参与SC的交叉下行和同侧腹侧上行投射。此外，大约一半的X神经元的轴突系统包括循环侧支。5. T神经元主要分布在视膜腹侧层和灰质中层背侧层。它们具有小型或中型，梯形或卵形细胞体和相对简单的辐射或垂直树突状树。它们的轴突通常参与两个主要的构造束，除了提供一个互交成分和循环侧枝。6. 本研究揭示的形态学细节支持这样的观点，即不同的构造轴突系统起源于灵长类SC的传出神经元，它们在顶盖中的位置以及它们的躯体和树突树的外观都不同。所得到的顶叶传出细胞的形态学分类为分析已识别神经元群体的顶叶功能提供了一个框架。
1. Neurons in the superior colliculus (SC) of anesthetized paralyzed squirrel monkeys were injected intracellularly with horseradish peroxidase (HRP) to establish a morphological classification of tectal efferent neurons in this species. These neurons were physiologically identified by their antidromic responses following stimulation of the contralateral predorsal bundle or SC. These cells also responded with postsynaptic potentials to stimulation of the ipsilateral substantia nigra and cerebral peduncle and the contralateral tectum. 2. Quantitative light microscopic analysis of the somatodendritic profiles and axonal trajectories of 27 recovered cells revealed the existence of three major groups of tectal efferent neurons: L (n = 7), X (n = 8), and T (n = 12). 3. L neurons are small or medium size cells with relatively elaborate dendritic trees and are located mainly in the superficial layers of the SC. They participate in the ipsilateral descending and dorsal ascending tectofugal bundles. Intrinsic collaterals of L axons deploy a large number of boutons both near the parent cell body and more ventrally within the deeper tectal layers. 4. X neurons are mostly large in size and multipolar in shape with relatively complex dendritic trees. Their cell bodies are situated mainly in the stratum griseum intermedium and occasionally in the stratum opticum. Axons of X neurons participate in the crossed descending and ipsilateral ventral ascending projections of the SC. In addition, the axonal system of about half of the X neurons includes recurrent collaterals. 5. T neurons are located mainly in the ventral stratum opticum and the dorsal stratum griseum intermedium. They have small or medium-sized, trapezoid or ovoid cell bodies and relatively simple radiating or vertical dendritic trees. Their axons usually participate in two of the major tectofugal bundles besides providing a commissural component and recurrent collaterals. 6. Morphological details revealed in the present study support the notion that distinct tectofugal axonal systems originate from efferent neurons of the primate SC that differ both as to their location in the tectum as well as the appearance of their somata and dendritic trees. The resulting morphological classification of tectal efferent cells provides a framework for the analysis of tectal function in terms of populations of identified neurons.