Projections from the spinal trigeminal nucleus to the cochlear nucleus in the rat
Projections from the spinal trigeminal nucleus to the cochlear nucleus in the rat
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DOI：
10.1002/cne.20466
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发表时间：
2005-04-04
影响因子：
2.5
通讯作者：
Ryugo, DK
中科院分区：
文献类型：
--
作者：
Haenggeli, CA;Pongstaporn, T;Ryugo, DK
跨感觉模态的信息整合使得声音能够在位置、运动和对象身份的背景下被处理。耳蜗核颗粒细胞区（GCD）的输入已被证明来自体感脑干结构，但三叉神经脊束核投射的性质尚不清楚。在本研究中，我们标记的三叉神经脊束神经元投射到耳蜗核使用逆行示踪剂，快蓝，并绘制其分布。在第二组实验中，我们将顺行示踪剂生物素化葡聚糖胺注射到三叉神经脊束核中，并用光学显微镜和电子显微镜研究了由此产生的顺行投射。三叉神经脊束神经元主要分布在尾侧部和极间部，并向耳蜗核提供输入。它们的轴突在GCD和耳蜗背核深层产生小的（直径1-3 μ m）的传递轴突和终末终扣。较少的情况下，较大的（3-15 μ m直径）分叶状终末被称为苔藓纤维分布在GCD。背侧放置的注射有一个额外的投影到前腹侧耳蜗核，而背侧放置的注射有一个额外的投影到后腹侧耳蜗核。所有的末梢都充满了圆形的突触囊泡，并与突触后靶点形成不对称的特化，这意味着它们本质上是兴奋性的。这些终末的突触后靶点包括颗粒细胞的树突。这些投射为躯体感觉信息提供了结构基底，以影响中枢听觉通路最早水平的听觉处理。(C)2005 Wiley-Liss，Inc.
The integration of information across sensory modalities enables sound to be processed in the context of position, movement, and object identity. Inputs to the granule cell domain (GCD) of the cochlear nucleus have been shown to arise from somatosensory brain stem structures, but the nature of the projection from the spinal trigeminal nucleus is unknown. In the present study, we labeled spinal trigeminal neurons projecting to the cochlear nucleus using the retrograde tracer, Fast Blue, and mapped their distribution. In a second set of experiments, we injected the anterograde tracer biotinylated dextran amine into the spinal trigeminal nucleus and studied the resulting anterograde projections with light and electron microscopy. Spinal trigeminal neurons were distributed primarily in pars caudalis and interpolaris and provided inputs to the cochlear nucleus. Their axons gave rise to small (1-3 mum in diameter) en passant swellings and terminal boutons in the GCD and deep layers of the dorsal cochlear nucleus. Less frequently, larger (3-15 mum in diameter) lobulated endings known as mossy fibers were distributed within the GCD. Ventrally placed injections had an additional projection into the anteroventral cochlear nucleus, whereas dorsally placed injections had an additional projection into the posteroventral cochlear nucleus. All endings were filled with round synaptic vesicles and formed asymmetric specializations with postsynaptic targets, implying that they are excitatory in nature. The postsynaptic targets of these terminals included dendrites of granule cells. These projections provide a structural substrate for somatosensory information to influence auditory processing at the earliest level of the central auditory pathways. (C) 2005 Wiley-Liss, Inc.