Deniau J M, Menetrey A, Charpier S
Université Pierre et Marie Curie, Département de Neurochimie-Anatomie, Paris, France.
Neuroscience. 1996 Aug;73(3):761-81. doi: 10.1016/0306-4522(96)00088-7.
The striatonigral pathway provides one of the most direct routes for information flow through the basal ganglia system. Via this pathway information from sensory, motor and associative areas of the cerebral cortex are routed to a variety of thalamocortical and brainstem networks involved in the organization of motor behaviour. In a previous analysis of the rat substantia nigra pars reticulata we have shown that the nigral cells which project to thalamus, tectum and tegmentum are topographically ordered along a series of curved laminae. Extending these observations, the present study examined how striatal regions related to particular areas of the cerebral cortex innervate the lamellar keyboard of nigral output neurons. For this purpose, small microiontophoretic injections of wheat germ agglutinin conjugated to horseradish peroxidase were performed in the striatum and the distribution of retrogradely-labelled cells in the cerebral cortex and anterogradely-labelled axons in the substantia nigra were conjointly examined. The results indicate that with the exception of the striatal region related to the allocortex, all the various components of the striatal functional mosaic are represented in the substantia nigra pars reticulata. This representation is organized under the form of longitudinal bands which compose a series of curved laminae enveloping a core located dorsolaterally in the substantia nigra. The striatal mapping in substantia nigra pars reticulata is such that the projections of the auditory and visual compartments are confined to the most ventral lamina. More dorsally, an ordered representation of the body is achieved by the nigral lamination. The oral and perioral body parts are centred on the dorsolateral core and the more distal parts of the face and limbs are progressively set out in more peripheral laminae. In the region affiliated to the prefrontal cortex, the dorsal cingulate district innervate a ventromedial lamina, the prelimbic/insular district lie dorsal to it. Projections from lateral orbital and insular compartments extend laterally along the dorsal margin of the pars reticulata. Since the "onion-like" distribution of striatal inputs is precisely the form observed in the distribution of nigral efferent neurons, the present observations favour the view that the nigral lamination underlies formation of specific input-output channels of processing. Evidence is considered that these channels are specialized for particular classes of movements or behaviours and integrate the various information relevant to the completion of these movements or behaviours.
纹状体黑质通路是信息流经基底神经节系统最直接的途径之一。通过这条通路，来自大脑皮质感觉、运动和联合区域的信息被传递到参与运动行为组织的各种丘脑皮质和脑干网络。在之前对大鼠黑质网状部的分析中，我们已经表明，投射到丘脑、顶盖和被盖的黑质细胞沿一系列弯曲的薄片呈拓扑有序排列。扩展这些观察结果，本研究考察了与大脑皮质特定区域相关的纹状体区域如何支配黑质输出神经元的层状结构。为此，在纹状体中进行了与辣根过氧化物酶结合的小麦胚芽凝集素的微量离子电泳小注射，并联合检查了大脑皮质中逆行标记细胞的分布以及黑质中顺行标记轴突的分布。结果表明，除了与allocortex相关的纹状体区域外，纹状体功能镶嵌的所有不同成分都在黑质网状部有所体现。这种体现以纵向带的形式组织起来，这些纵向带构成了一系列弯曲的薄片，包围着位于黑质背外侧的一个核心。黑质网状部的纹状体映射使得听觉和视觉区的投射局限于最腹侧的薄片。在更靠背侧的位置，黑质的分层实现了身体的有序表征。口腔和口周身体部位集中在背外侧核心，面部和四肢的更远端部位则逐渐分布在更外围的薄片中。在与前额叶皮质相关的区域，背侧扣带区支配一个腹内侧薄片，前边缘/岛叶区位于其背侧。来自外侧眶和岛叶区的投射沿着网状部背缘横向延伸。由于纹状体输入的“洋葱样”分布正是在黑质传出神经元分布中观察到的形式，目前的观察结果支持这样一种观点，即黑质分层是处理特定输入 - 输出通道形成的基础。有证据表明，这些通道专门用于特定类别的运动或行为，并整合与完成这些运动或行为相关的各种信息。
