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外侧丘系腹核在声信号加工和听觉上行传导中的作用

刘慧华, 罗峰, 王欣^*

华中师范大学生命科学学院和遗传调控与整合生物学湖北省重点实验室，武汉 430079

摘要

外侧丘系腹核(ventral nucleus of the lateral lemniscus, VNLL)是中枢听觉通路中连接耳蜗核等低位脑干和中脑下丘(inferior colliculus, IC)的重要核团，其神经元能够对声信号的不同参数进行检测与加工，进而形成多样的声反应特性。VNLL神经元对频率反应的调谐曲线有多种类型，但其锐化程度一般较低，对频率的分析亦不够精确；有关强度调谐的放电率函数分为两种类型：单调型与非单调型，它们对强度的加工和编码往往受到发放模式的影响；不同发放模式的VNLL神经元对时程的编码能力不同，其中起始型具有精确的时间特性，适合编码声刺激的起始时间信息，对蝙蝠的回声定位非常重要。VNLL接受来自低位核团的输入，并发出上行的抑制性投射至IC，在IC神经元的声信息检测过程中发挥重要作用。近来研究认为VNLL快速的抑制性投射延迟IC神经元的首次发放潜伏期，VNLL延迟的抑制性投射介导IC神经元的发放模式，但VNLL抑制性输入如何在IC进行整合，并增强IC神经元检测声信号能力的机制并不清楚，且缺乏VNLL对IC进行实时调控作用的直接证据。这些问题的研究有助于进一步认识上行输入在声信号加工过程中的作用，同时也是本实验室今后的研究重点。本文结合本实验室相关研究，围绕VNLL对听觉信号的加工和上行传导进行综述。

关键词： 外侧丘系腹核; 声信号加工; 听觉上行传导; 下丘

分类号：Q437

[The role of the ventral nucleus of the lateral lemniscus in sound signal processing and auditory ascending transmission.] [Article in Chinese]

LIU Hui-Hua, LUO Feng, WANG Xin^*

College of Life Sciences and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, China

Abstract

The ventral nucleus of the lateral lemniscus (VNLL) is an important nucleus in the central auditory pathway which connects the lower brainstem and the midbrain inferior colliculus (IC). Previous studies have demonstrated that neurons in the VNLL could respond to sound signal parameters. Frequency tuning curves (FTCs) of VNLL neurons are generally wider than FTCs of IC neurons, suggesting that the VNLL does not enhance abilities of frequency discrimination and coding. Two types of rate-intensity functions (RIFs) are found in the VNLL: monotonic and non-monotonic RIFs. Intensity-tuning of VNLL neurons are affected by the temporal firing patterns during processing and encoding intensity. There are multiple temporal firing patterns in VNLL neurons. Onset pattern has a precise timing characteristic which is well suited to encode temporal features of stimuli, and also very important to animal behavior including bat's echolocation. The VNLL accepts inputs from lower nuclei, uploads glycine inhibitory outputs to IC, and modulates response characteristics generating and acoustic signal processing of IC neurons. Recent research suggests that fast inhibitory projection from the VNLL may delay the first spike latency of IC neurons, and the delayed inhibitory projection from the VNLL may mediate the temporal firing patterns of IC neurons. But how inhibitory inputs from the VNLL integrate in IC, and how inhibitory inputs from the VNLL enhance the ability of detecting sound signal of IC neurons are not very clear and need more direct evidence at the level of neurons. These questions will help further understand the role of upload during IC processes acoustic signal, which are our research target in the future. This article reviews the current literature regarding the roles of the VNLL in sound signal processing and the auditory ascending transmission, including advances in the relevant research in our laboratory.

Key words: ventral nucleus of the lateral lemniscus; sound signal processing; auditory ascending transmission; inferior colliculus

收稿日期：2013-10-21　　录用日期：2014-01-20

通讯作者：王欣　　E-mail: xueyue312@aliyun.com

引用本文：

刘慧华, 罗峰, 王欣. 外侧丘系腹核在声信号加工和听觉上行传导中的作用[J]. 生理学报 2014; 66 (3): 358-364.

LIU Hui-Hua, LUO Feng, WANG Xin. [The role of the ventral nucleus of the lateral lemniscus in sound signal processing and auditory ascending transmission.] [Article in Chinese]. Acta Physiol Sin 2014; 66 (3): 358-364 (in Chinese with English abstract).