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中枢听觉系统对声音时程的调谐和识别

王欣, 李安安, 吴飞健

华中师范大学生命科学学院，武汉 430079；湖北第二师范学院化学与生命科学系，武汉 430205；中国科学院武汉物理与数学研究所/ 波谱与原子分子物理国家重点实验室，武汉 430071

摘要

声音的时程信息对动物的声通讯和人的言语识别非常重要。声信号中的大部分信息都编码在随时间变化的振幅和频谱中。听中枢神经元对声音时程的调谐先后在蛙、蝙蝠、小鼠等动物的下丘及以上结构内发现，其在声信号识别和声信息承载方面发挥重要作用；以人为对象的心理物理学研究也观察到发声的时程对语音识别和语义分析非常重要。时程调谐的神经机制目前尚不清楚，可能是兴奋性输入和抑制性输入按某种模式进行的整合。巧合检测模型和反巧合模型等可解
释某些类型的时程选择性神经元上的调谐机制，而神经元自身的结构特性也可能与时程调谐的形成有关。时程调谐还受到声音的其他参量(如频谱构成、强度、重复率等)影响，时程选择性神经元可根据这些参量的动态变化凸显特殊生境下的有意义声信号。本文在相关研究工作基础之上，结合本实验室的研究结果，对中枢听神经元的时程编码特性和机制，以及某些声信号参数对神经元时程编码的影响和时程调谐的生物学意义作介绍和评述。

关键词： 时程调谐; 时间整合; 中枢听觉系统; 下丘

分类号：Q437

[Perception and selectivity of sound duration in the central auditory midbrain.] [Ariticle in Chinese]

WANG Xin, LI An-An, WU Fei-Jian

College of Life Science, Central China Normal University, Wuhan 430079, China； Department of Life Sciences and Chemistry, Hubei University of Education, Wuhan 430205, China； Wuhan Institute of Physics and Mathematics, the Chinese Academy of Sciences/State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan 430071, China

Abstract

Sound duration plays important role in acoustic communication. Information of acoustic signal is mainly encoded in the amplitude and frequency spectrum of different durations. Duration selective neurons exist in the central auditory system including inferior colliculus (IC) of frog, bat, mouse and chinchilla, etc., and they are important in signal recognition and feature detection. Two
generally accepted models, which are “coincidence detector model” and “anti-coincidence detector model”, have been raised to explain the mechanism of neural selective responses to sound durations based on the study of IC neurons in bats. Although they are different in details, they both emphasize the importance of synaptic integration of excitatory and inhibitory inputs, and are able to explain the responses of most duration-selective neurons. However, both of the hypotheses need to be improved since other sound parameters, such as spectral pattern, amplitude and repetition rate, could affect the duration selectivity of the neurons. The dynamic changes of
sound parameters are believed to enable the animal to effectively perform recognition of behavior related acoustic signals. Under free
field sound stimulation, we analyzed the neural responses in the IC and auditory cortex of mouse and bat to sounds with different
duration, frequency and amplitude, using intracellular or extracellular recording techniques. Based on our work and previous studies,
this article reviews the properties of duration selectivity in central auditory system and discusses the mechanisms of duration
selectivity and the effect of other sound parameters on the duration coding of auditory neurons.

Key words: duration tuning; temporal integration; central auditory system; inferior colliculus

收稿日期：2010-02-22　　录用日期：2010-06-09

通讯作者：吴飞健　　E-mail: wufj@mail.ccnu.edu.cn

引用本文：

王欣, 李安安, 吴飞健. 中枢听觉系统对声音时程的调谐和识别[J]. 生理学报 2010; 62 (4): 309-316.

WANG Xin, LI An-An, WU Fei-Jian. [Perception and selectivity of sound duration in the central auditory midbrain.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (4): 309-316 (in Chinese with English abstract).