Winer J A, Wenstrup J J
Department of Molecular and Cell Biology, University of California at Berkeley 94720-3200.
J Comp Neurol. 1994 Aug 8;346(2):183-206. doi: 10.1002/cne.903460203.
The neurons in the medial geniculate body were studied in Golgi preparations from adult mustached bats (Pteronotus parnellii). Their somatic and dendritic configurations were compared with those of cells in other, nonecholocating mammals. A second goal was to use the thalamic nuclear subdivisions derived from Golgi material to integrate the findings in parallel studies of cytoarchitecture, immunocytochemistry, and tectothalamic connections. Three primary divisions are defined. The ventral division is large and has a stereotyped neuronal organization. Medium-sized perikarya (about 10 microns in diameter) represent tufted neurons; the fibrodendritic plexus forms laminae in the lateral part along which midbrain axons terminate. A smaller, possibly intrinsic, neuron with thin, sparse dendrites is rarely impregnated. Neurons in the larger, medial part, which represents frequencies of 60 kHz and higher, have more spherical dendritic fields; their branching pattern remains tufted, and the laminar organization was less evident. The dorsal division is about equal in size, and it has many nuclei and a corresponding neuronal diversity. These neurons are medium-sized except in the suprageniculate nucleus, where many cells are larger. Four dorsal division nuclei are recognized. Each has neurons with radiate or weakly tufted dendritic arbors. Superficial dorsal nucleus neurons are oriented from medial to lateral, imparting a slightly laminated appearance to the neuropil. A few smaller, stellate neurons with modest dendritic domains are present. Suprageniculate nucleus neurons have radiating dendritic fields that project spherically; they have fewer branches than dorsal nucleus neurons. The posterior limitans nucleus is dorsomedial to the suprageniculate nucleus; it has small neurons with long, sparsely branched dendrites. The rostral pole nucleus, included in the dorsal division on cytoarchitectonic grounds, had too few neurons impregnated to reveal its neuronal architecture. The medial division, the smallest of the main parts, is one nucleus with at least six types of cells, including the magnocellular, bushy tufted, disc-shaped, medium-sized multipolar, elongated, and small stellate neurons. There is no laminar arrangement. Many of the neurons resemble those in rodent, marsupial, carnivore, and primate auditory thalamic nuclei. Despite such morphological correspondences, functional differences, such as the evolution of combination sensitivity, suggest that structurally comparable auditory thalamic neurons may subserve diverse physiological representations.
对成年须鼻蝠（Pteronotus parnellii）的内侧膝状体中的神经元进行了高尔基染色标本研究。将它们的胞体和树突形态与其他非回声定位哺乳动物的细胞形态进行了比较。第二个目标是利用从高尔基染色材料得出的丘脑核亚区，将细胞结构学、免疫细胞化学以及顶盖丘脑连接的平行研究结果整合起来。定义了三个主要分区。腹侧分区较大，具有刻板的神经元组织。中等大小的胞体（直径约10微米）代表簇状神经元；纤维树突丛在外侧部分形成层，中脑轴突沿此层终止。一种较小的、可能是固有性的神经元，其树突细且稀疏，很少被浸染。内侧较大部分的神经元代表60千赫及更高的频率，具有更多球形的树突野；它们的分支模式仍为簇状，层状组织不太明显。背侧分区大小相近，有许多核以及相应的神经元多样性。除了上膝状核中的许多细胞较大外，这些神经元都是中等大小。识别出四个背侧分区分核。每个分核都有放射状或弱簇状树突分支的神经元。浅表背核神经元从内侧向外侧排列，使神经毡呈现出轻微的层状外观。存在一些较小的、具有适度树突域的星状神经元。上膝状核神经元具有呈球形投射的放射状树突野；它们的分支比背核神经元少。后界核位于上膝状核的背内侧；它有小神经元，其树突长且分支稀疏。根据细胞结构学，位于背侧分区的嘴侧极核浸染的神经元太少，无法揭示其神经元结构。内侧分区是主要部分中最小的，是一个核，至少有六种类型的细胞，包括大细胞、浓密簇状、盘状、中等大小多极、细长和小星状神经元。没有层状排列。许多神经元类似于啮齿动物、有袋动物、食肉动物和灵长类动物听觉丘脑核中的神经元。尽管有这种形态学上的对应关系，但功能上的差异，如组合敏感性的进化，表明结构上可比的听觉丘脑神经元可能具有不同的生理表现。
