Organization of binaural excitatory and inhibitory inputs to the inferior colliculus from the superior olive
Organization of binaural excitatory and inhibitory inputs to the inferior colliculus from the superior olive
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DOI：
10.1002/cne.20070
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发表时间：
2004-05-03
影响因子：
2.5
通讯作者：
Oliver, DL
中科院分区：
文献类型：
--
作者：
Loftus, WC;Bishop, DC;Oliver, DL
传入下丘中央核（ICC）的主要兴奋性双耳神经元来自同侧内侧上级橄榄核（MSO）和对侧外侧上级橄榄核（LSO）两组功能不同的神经元。一个主要的抑制，双耳输入出现在同侧LSO的甘氨酸能神经元。为了确定这些输入是否收敛于ICC中相同的突触后靶点，将两种不同的顺行示踪剂注射到同一动物的MSO和LSO的对侧的tonotopically匹配区域。主要研究结果是，终扣从MSO轴突终止主要在中央和尾部的ICC板，但对侧LSO终端集中更rostrally和腹侧边缘的MSO输入。相反，同侧LSO投影与MSO输入收敛，并且比对侧LSO投影更密集。与这一发现相一致，逆行运输实验表明，非常低的频率区域的ICC密集的MSO输入也收到了更多的同侧LSO神经元比对侧LSO神经元的输入。结果表明，通过低频ICC的不同双耳通路可能是由MSO和对侧LSO对ICC的兴奋性输入的分离形成的。同时，同侧LSO在MSO的靶区域中是主要的抑制性影响。这些数据支持这样的概念，即ICC中的每个频带层可以包括具有不同输入组合的几个功能模块。(C)2004威利-利斯公司
The major excitatory, binaural inputs to the central nucleus of the inferior colliculus (ICC) are from two groups of neurons with different functions-the ipsilateral medial superior olive (MSO) and the contralateral lateral superior olive (LSO). A major inhibitory, binaural input emerges from glycinergic neurons in the ipsilateral LSO. To determine whether these inputs converge on the same postsynaptic targets in the ICC, two different anterograde tracers were injected in tonotopically matched areas of the MSO and the LSO on the opposite side in the same animal. The main findings were that the boutons from MSO axons terminated primarily in the central and caudal parts of the ICC laminae but that contralateral LSO terminals were concentrated more rostrally and on the ventral margins of the MSO inputs. In contrast, the ipsilateral LSO projection converged with the MSO inputs and was denser than the contralateral LSO projection. Consistent with this finding, retrograde transport experiments showed that the very low-frequency areas of the ICC with dense MSO inputs also received inputs from greater numbers of ipsilateral LSO neurons than from contralateral LSO neurons. The results suggest that different binaural pathways through the low-frequency ICC may be formed by the segregation of excitatory inputs to ICC from the MSO and the contralateral LSO. At the same time, the ipsilateral LSO is a major inhibitory influence in the target region of the MSO. These data support the concept that each frequency-band lamina in the ICC may comprise several functional modules with different combinations of inputs. (C) 2004 Wiley-Liss, Inc.