Wenstrup J J, Larue D T, Winer J A
Department of Neurobiology, Northeastern Ohio Universities College of Medicine, Rootstown 44272-0095.
J Comp Neurol. 1994 Aug 8;346(2):207-36. doi: 10.1002/cne.903460204.
This study examined the output of the central nucleus of the inferior colliculus to the medial geniculate body and other parts of the nervous system in the mustached bat (Pteronotus parnellii). Small deposits of anterograde tracers (horseradish peroxidase, [3H]leucine, Phaseolus vulgaris leucoagglutinin, wheat germ agglutinin conjugated to horseradish peroxidase, or biocytin) were made at physiologically defined sites in the central nucleus representing major components of the bat's echolocation signal. The topography, frequency specificity, and axonal morphology of these outputs were studied. The medial geniculate body was a major target of inferior collicular neurons, with three distinct input patterns. The projection to the ventral division was tonotopically organized, but had a relatively sparse contribution from neurons representing frequency modulated components of the biosonar pulse. The second input was to the rostral medial geniculate body, in which projections from inferior collicular neurons representing constant frequency sonar components were separated from those representing frequency modulated components. A third input was to the suprageniculate nucleus, which received strong, topographically arranged projections. Inputs to the dorsal nucleus and medial division were also observed. Extrathalamic regions receiving input included the pontine gray, external nucleus of the inferior colliculus, pericollicular tegmentum, nucleus of the brachium of the inferior colliculus, and pretectum. These central nucleus projections differed in organization and the structure of axon terminals, suggesting different physiological influences on their target nuclei. These results demonstrate that the central nucleus has divergent projections to various sensory and premotor nuclei, besides its well-established projection to the medial geniculate body.
本研究考察了髯蝠（Pteronotus parnellii）下丘中央核向内侧膝状体及神经系统其他部分的投射。将顺行示踪剂（辣根过氧化物酶、[3H]亮氨酸、菜豆白细胞凝集素、与辣根过氧化物酶偶联的小麦胚凝集素或生物素）的小剂量沉积物注入下丘中央核中生理定义的位点，这些位点代表了蝙蝠回声定位信号的主要成分。研究了这些投射的拓扑结构、频率特异性和轴突形态。内侧膝状体是下丘神经元的主要靶标，具有三种不同的输入模式。向下丘腹侧部的投射是按音频拓扑组织的，但代表生物声纳脉冲调频成分的神经元的贡献相对较少。第二种输入是到内侧膝状体嘴侧部，其中代表恒频声纳成分的下丘神经元投射与代表调频成分的投射是分开的。第三种输入是到上膝状体核，它接受强烈的、按拓扑排列的投射。也观察到了向下丘脑背核和内侧部的输入。接受输入的丘脑外区域包括脑桥灰质、下丘外侧核、丘周被盖、下丘臂核和顶盖前区。这些中央核投射在组织和轴突终末结构上有所不同，表明它们对靶核有不同的生理影响。这些结果表明，除了其已确定的向内侧膝状体的投射外，中央核还向各种感觉和运动前核发出了发散性投射。
