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清醒小鼠丘脑网状核的听觉响应特性

李宇铧, 宋长宝, 梁妃学^*

南方医科大学生物医学工程学院，广州 510515

摘要

本文旨在探究清醒小鼠的丘脑网状核(thalamic reticular nucleus, TRN)在听觉信息处理过程中展现的听觉响应特性，以加深对TRN的理解并探究TRN在听觉系统中的作用。通过对18只SPF级C57BL/6J小鼠TRN中的神经元进行在体电生理单细胞贴附式记录，本研究观察了314个TRN神经元对噪声和纯音这两种听觉刺激的响应。结果显示，TRN接收来自初级听觉皮层(primary auditory cortex, A1)第六层的投射。在314个所记录的TRN神经元中，56.05%没有声响应，21.02%只对噪声有响应，22.93%对噪声和纯音均有响应。有噪声响应的神经元根据响应时间可以分为三种类型：给声开始(onset)型、给声持续(sustain)型和长时程响应(long-lasting)型，各占73.19%、14.49%和12.32%。给声持续型神经元的响应阈值低于其他两种类型。在噪声刺激下，与A1第六层神经元相比，TRN神经元表现出听觉响应不稳定(P < 0.001)，神经元自发放电频率高(P < 0.001)，响应延时长(P < 0.001)的特点；而在纯音刺激下，TRN神经元的响应连续性较差，频率调谐较之A1第六层差异极大(P < 0.001)，但是两者对纯音的声频率敏感性却是相当的(P > 0.05)，且TRN的纯音响应阈值远高于A1第六层(P < 0.001)。以上结果表明，TRN在听觉系统中主要承担信息传递的任务，TRN的噪声响应较纯音响应更广泛，总体上TRN偏向于高强度的声刺激。

关键词： 小鼠; 丘脑网状核; 听觉; 在体电生理

Auditory response of the reticular nucleus of thalamus in awake mice

LI Yu-Hua, SONG Chang-Bao, LIANG Fei-Xue^*

College of Biomedical Engineering, South Medical University, Guangzhou 510515, China

Abstract

This study aims to explore the auditory response characteristics of the thalamic reticular nucleus (TRN) in awake mice during auditory information processing, so as to deepen the understanding of TRN and explore its role in the auditory system. By in vivo electrophysiological single cell attached recording of TRN neurons in 18 SPF C57BL/6J mice, we observed the responses of 314 recorded neurons to two kinds of auditory stimuli, noise and tone, applied to mice. The results showed that TRN received projections from layer six of the primary auditory cortex (A1). Among 314 TRN neurons, 56.05% responded silently, 21.02% responded only to noise and 22.93% responded to both noise and tone. The neurons with noise response can be divided into three patterns according to their response time: onset, sustain and long-lasting, accounting for 73.19%, 14.49% and 12.32%, respectively. The response threshold of the sustain pattern neurons was lower than those of the other two types. Under noise stimulation, compared with A1 layer six, TRN neurons showed unstable auditory response (P < 0.001), higher spontaneous firing rate (P < 0.001), and longer response latency (P < 0.001). Under tone stimulation, TRN’s response continuity was poor, and the frequency tuning was greatly different from that of A1 layer six (P < 0.001), but their sensitivity to tone was similar (P > 0.05), and TRN’s tone response threshold was much higher than that of A1 layer six (P < 0.001). The above results demonstrate that TRN mainly undertakes the task of information transmission in the auditory system. The noise response of TRN is more extensive than the tone response. Generally, TRN prefers high-intensity acoustic stimulation.

Key words: Mice; thalamic reticular nucleus; auditory sensation; in vivo electrophysiology

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通讯作者：梁妃学　　E-mail: lfx_2@hotmail.com

引用本文：

李宇铧, 宋长宝, 梁妃学. 清醒小鼠丘脑网状核的听觉响应特性[J]. 生理学报 2023; 75 (3): 360-368.

LI Yu-Hua, SONG Chang-Bao, LIANG Fei-Xue. Auditory response of the reticular nucleus of thalamus in awake mice. Acta Physiol Sin 2023; 75 (3): 360-368 (in Chinese with English abstract).