Circuits for processing dynamic interaural intensity disparities in the inferior colliculus.
Circuits for processing dynamic interaural intensity disparities in the inferior colliculus.
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DOI：
10.1016/j.heares.2012.01.011
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发表时间：
2012-06
期刊：
影响因子：
2.8
通讯作者：
Pollak GD
中科院分区：
文献类型：
--
作者：
Pollak GD
耳间强度差异（IID），所有动物用于定位高频声音的线索，最初在外侧上级橄榄（LSO）中通过减法过程进行处理，其中来自一只耳朵的输入兴奋而来自另一只耳朵的输入抑制LSO神经元。这种细胞被称为兴奋抑制（EI）神经元，不仅在LSO中突出，而且在高级核中也突出，包括外侧丘系背核（DNLL）和下丘（IC）。IC是特别感兴趣的，因为它的EI细胞从大量的较低的核，其中包括DNLL和LSO接收不同的神经支配模式，因此包括具有不同双耳特性的人口。本文的第一部分重点介绍了在LSO、DNLL和IC中产生EI细胞的电路。第二部分然后转向随时间变化的动态IID引起的响应，如从不同空间区域或移动声源发出的多个声音。我发现，许多EI神经元在IC响应动态IID的方式是不可预测的，从他们的响应静态IID，IID一次一个。在最后一节中，结果从体内全细胞记录在IC和地址的连接的基础上动态IID的反应。主要结论是EI细胞包括一个多样化的群体。多样性是由每个EI类型接收的特定输入集创建的，并以这些输入生成的动态IID响应的差异表示。这些结果表明，IC中EI神经元的构建赋予了不仅编码单个声源位置的功能，而且还允许动物确定移动声音的方向，并在许多声音中集中和定位单个声音，就像所有动物的日常生活中通常发生的那样。
Interaural intensity disparities (IIDs), the cues all animals use to localize high frequency sounds, are initially processed in the lateral superior olive (LSO) by a subtractive process where inputs from one ear excite and inputs from the other ear inhibit LSO neurons. Such cells are called excitatory-inhibitory (EI) neurons and are prominent not only in the LSO but also in higher nuclei, which include the dorsal nucleus of the lateral lemniscus (DNLL) and inferior colliculus (IC). The IC is of particular interest since its EI cells receive diverse innervation patterns from a large number of lower nuclei, which include the DNLLs and LSOs, and thus comprise a population with diverse binaural properties. The first part of this review focuses on the circuits that create EI cells in the LSO, DNLL and IC. The second section then turns to the responses evoked by dynamic IIDs that change over time, as with multiple sounds that emanate from different regions of space or moving sound sources. I show that many EI neurons in the IC respond to dynamic IIDs in ways that are not predictable from their responses to static IIDs, IIDs presented one at a time. In the final section, results from in vivo whole cell recording in the IC are presented and address the connectional basis for the responsiveness to dynamic IIDs. The principal conclusion is that EI cells comprise a diverse population. The diversity is created by the particular set of inputs each EI type receives and is expressed in the differences in the responses to dynamic IIDs that are generated by those inputs. These results show that the construction of EI neurons in the IC imparts features that not only encode the location of an individual sound source, but also that allow animals to determine the direction of a moving sound and to focus and localize a single sound in midst of many sounds, as typically occurs in the daily lives of all animals.