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调频声的调制范围和刺激呈现率对小鼠下丘神经元听反应的影响

李安安, 张艾娅, 陈其才, 吴飞健

华中师范大学生命科学学院，基因调控与整合生物学湖北省重点实验室，武汉430079； 湖北第二师范学院化学与生命科学系，武汉430205

摘要

在自然声环境中，多数与生命活动相关的声音都包含有调频声成分，这些调频声往往都具有不同的调制范围和重复率。本研究采用常规电生理技术检测小鼠下丘神经元对具有不同调制范围和刺激呈现率声信号的反应情况。在所记录的90 个下丘神经元中，超过60% 的神经元对较窄的调制范围有最好的反应(窄通型，上扫：60.00%, 54/90；下扫：63.33%，57/90)，其它少部分的反应类型有带通型(上扫：16.67%，15/90；下扫：18.89%，17/90)、宽通型(上扫：4.44%, 4/90；下扫：4.44%, 4/90)和全通型(上扫：18.89%, 17/90；下扫：13.33%, 12/90)。当使用不同的刺激呈现率后(从0.5 次/s 到10 次/s)，神经元的发放率和发放时程随着刺激呈现率的升高而缩短，而潜伏期则逐渐增加。另外，调制范围和刺激呈现率都会影响下丘神经元对调频声上下扫的方向选择性。以上结果表明小鼠中脑下丘神经元对调频声刺激反应的时相特征可受到调制范围和刺激呈现率的调制，其神经机制可能与下丘神经元的频谱以及时相整合有关。

关键词： 调频声; 调制范围; 方向选择性; 刺激呈现率; 下丘; 小鼠

分类号：Q437

Effects of modulation range and presentation rate of FM stimulus on auditory response properties of mouse inferior collicular neurons

LI An-An, ZHANG Ai-Ya, CHEN Qi-Cai, WU Fei-Jian

College of Life Sciences and Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University, Wuhan 430079, China； Department of Life Sciences and Chemistry, Hubei University of Education, Wuhan 430205, China

Abstract

In natural acoustical environments, most biologically related sounds containing frequency-modulated (FM) componentsrepeat over periods of time. They are often in rapid sequence rather than in temporal isolation. Few studies examined the neuronalresponse patterns evoked by FM stimuli at different presentation rates (PR). In the present investigation, by using normalelectrophysiological technique, we specifically studied the temporal features of response of the inferior collicular (IC) neurons to FMsweeps with different modulation ranges (MR) in conditions of distinct PR in mouse. The results showed that most of the recordedneurons responded best to narrower MRs (narrow-pass, up-sweep: 60.00%, 54/90; down-sweep: 63.33%, 57/90), while a smallfraction of neurons displayed other patterns such as band-pass (up-sweep, 16.67%, 15/90; down-sweep, 18.89%, 17/90), all-pass (upsweep,18.89%, 17/90; down-sweep, 13.33%, 12/90) and wide-pass (up-sweep, 4.44%, 4/90; down-sweep, 4.44%, 4/90). Both thedischarge rate and duration of recorded neurons decreased but the latency lengthened with increase in PR, when different PRs from0.5/s to 10/s of FM sound were used. The percentage of total directional selective neurons, up-directional selective neurons, and downdirectionalselective neurons changed with the variation of PR or MR. These results indicate that temporal features of mouse midbrainneurons responding to FM sweeps are co-shaped by the MR and PR. Possible mechanisms underlying may be related to spectral andtemporal integration of the FM sound by the IC neurons.

Key words: frequency-modulated sweep; modulation range; directional selectivity; presentation rate; inferior colliculus; mouse

收稿日期：2010-03-09　　录用日期：2010-04-14

通讯作者：陈其才,吴飞健　　E-mail: qcchen2003@yahoo.com.cn,

引用本文：

李安安, 张艾娅, 陈其才, 吴飞健. 调频声的调制范围和刺激呈现率对小鼠下丘神经元听反应的影响[J]. 生理学报 2010; 62 (3): 210-218.

LI An-An, ZHANG Ai-Ya, CHEN Qi-Cai, WU Fei-Jian. Effects of modulation range and presentation rate of FM stimulus on auditory response properties of mouse inferior collicular neurons. Acta Physiol Sin 2010; 62 (3): 210-218 (in Chinese with English abstract).