Merchán M A, Berbel P
Departamento de Biología Celular y Patología, Universidad de Salamanca, Spain.
J Comp Neurol. 1996 Aug 19;372(2):245-63. doi: 10.1002/(SICI)1096-9861(19960819)372:2<245::AID-CNE7>3.0.CO;2-3.
The lateral lemniscus contains relay nuclei of the auditory pathway in which the neurons have been grouped into dorsal and ventral (VNLL) nuclei. The data about the cytoarchitecture of the VNLL are controversial and no agreement exists concerning its tonotopical organization. In this paper, the cytoarchitecture of VNLL and the spatial distribution of its neurons projecting to the central nucleus of the inferior colliculus (CNIC) have been studied by using different tracers. Rats were iontophoretically injected in the CNIC and grouped in three sets. Group 1 rats received large injections of biotinylated dextran amine (BDA). Group 2 animals received restricted single injections of BDA in the low-, medium-, or high-frequency regions of the CNIC. Group 3 rats were double injected, with horseradish peroxidase placed in the high-frequency region of the CNIC, and with biocytin in the low-frequency one. The distribution of retrogradely labeled neurons in the ipsilateral VNLL was three-dimensionally reconstructed by use of a computer microscope. The analysis of labeled neurons and Nissl material suggests that the VNLL contains flat stellate neurons. Labeled flat stellate neurons and fibers are oriented in parallel and form fibrodendritic laminae. The projection from the VNLL to the CNIC is topographically organized: neurons in peripheral laminae project to dorsolateral, low-frequency regions of the CNIC, and those of central laminae project to ventromedial, high-frequency regions. Each VNLL lamina forms a continuous ventrodorsal structure which resembles a helicoid.
外侧丘系包含听觉通路的中继核，其中的神经元已被分为背侧核和腹侧核（腹侧外侧丘系核）。关于腹侧外侧丘系核细胞构筑的数据存在争议，并且关于其音频拓扑组织也没有达成共识。在本文中，通过使用不同的示踪剂，研究了腹侧外侧丘系核的细胞构筑及其投射到下丘中央核（下丘中央核）的神经元的空间分布。将大鼠离子电渗注入下丘中央核，并分为三组。第1组大鼠接受大剂量生物素化葡聚糖胺（BDA）注射。第2组动物在下丘中央核的低频、中频或高频区域接受受限的单次BDA注射。第3组大鼠进行双重注射，将辣根过氧化物酶注入下丘中央核的高频区域，将生物胞素注入低频区域。使用计算机显微镜对同侧腹侧外侧丘系核中逆行标记神经元的分布进行三维重建。对标记神经元和尼氏物质的分析表明，腹侧外侧丘系核包含扁平星状神经元。标记的扁平星状神经元和纤维平行排列并形成纤维树突层。从腹侧外侧丘系核到下丘中央核的投射是按拓扑方式组织的：外周层的神经元投射到下丘中央核的背外侧低频区域，中央层的神经元投射到腹内侧高频区域。每个腹侧外侧丘系核层形成一个连续的腹背结构，类似于螺旋体。
