作者：
Jia Tang;Fei-Jian Wu;Dan Wang;Jen, Philip H. -S.;Qi-Cai Chen*
期刊：
CHINESE JOURNAL OF PHYSIOLOGY,2007年50(4):187-198 ISSN：0304-4920
通讯作者：
Qi-Cai Chen
作者机构：
[Qi-Cai Chen] Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.;Univ Missouri, Div Biol Sci, Columbia, MO 65211 USA.;Univ Missouri, Interdisciplinary Neurosci Program, Columbia, MO 65211 USA.
通讯机构：
[Qi-Cai Chen] C;Cent China Normal Univ, Coll Life Sci, Wuhan 430079, Peoples R China.
摘要：
Natural auditory environment consists of multiple sound sources that are embedded in ambient strong and weak noise. For effective sound communication and signal analysis, animals must somehow extract biologically relevant signals from the inevitable interference of ambient noise. The present study examined how a weak noise may affect the amplitude sensitivity of neurons in the mouse central nucleus of the inferior colliculus (IC) which receives convergent excitatory and inhibitory inputs from both lower and higher auditory centers. Specifically, we studied the amplitude sensitivity of IC neurons using a probe (best frequency pulse) and a masker (weak noise) under simultaneous masking paradigm. For most IC neurons, weak noise masking increases the minimum threshold and decreases the number of impulses. Noise masking also increased the slope and decreased the dynamic range of the rate amplitude function of these IC neurons. The strength of this noise masking was greater at low than at high sound amplitudes. This variation in the amplitude sensitivity of IC neurons in the presence of the weak noise was mostly mediated through GABAergic inhibition. These data indicate that in the real world the ambient weak noise improves amplitude sensitivity of IC neurons through GABAergic inhibition while inevitably decreases the range of overall auditory sensitivity of IC neurons.
作者：
Wang Dan;Pi Jianhui;Tan Jia;Tang Jia;Wu Feijian;...
期刊：
生理学报,2005年57(1):59-65 ISSN：0371-0874
通讯作者：
Wang, D.
作者机构：
[Wang Dan; Tang Jia; Tan Jia; Wu Feijian; Chen Qicai] School of Life Sciences, Central China Normal University;[Pi Jianhui] Department of Biology, Huaihua College of Hunan
摘要：
In order to explore the possible mechanisms by which ethologically relevant sounds can be extracted from complex auditory environments, this study examined the effects of weak noise on the rate-intensity functions (RIFs) of neurons responding to tone burst in the inferior colliculus (IC) of nine mice (Mus musculus Km). Under free field stimuli conditions, a total of 112 IC neurons were recorded. RIFs with and without simultaneous presentation of weak noise, of which the intensity was relative to 5 dB below minimum threshold of tone burst, were measured in 44 IC neurons. By means of evaluating the changes of dynamic range (DR), slope of RIFs, and percent inhibition at different tone burst intensities evoked by the weak noise, three types of variations in RIFs were observed, i. e.,inhibition (39/44, 88.6%), facilitation (2/44, 4.6%), and no effectiveness (3/44, 6.8%). Statistical analysis indicated that only inhibitory effect of weak noise was significant (P ＜ 0.001, n = 39). The inhibitory effect of weak noise was greater at lower stimulus intensity of tone burst but decreased significantly with increased stimulus intensity (P ＜ 0.0001, n = 39). In addition, the DR and slope of RIFs became narrower and steeper with weak noise presentation, respectively (P ＜ 0.01, n = 31). The results from the present study suggest that weak noise exerts a dynamic modulatory action on acoustical intensity sensitivity of IC neurons, which possibly leads to a better understanding of neural mechanisms underlying the extraction of sound signals from natural auditory scenes.
摘要：
<正>惺嗌窬谠肷跫路从Τ识嘌员浠?CostaluPes et al.,1984; Gibson etal.,1985:Phillips,1985:PhilliPs and Hall,1986:PhilliPs,1990;Ramaehandran et al.,2000),提示噪声环境中声信号的提取有听中枢机制的参与。
摘要：
In this paper, weak white noise was used to masker, and the effect of the intensity processing of mouse IC neurons on forward masking, backward masking and simultaneous masking was studied. The results showed, mean of MTs of IC neurons on three different masking by white noise were higher than its on tone (p ＜0.001), and there was significance (p ＜ 0.001) for the difference between MT of forward masking and MT of simultaneous masking and of backward masking. And effect of noise masking on spike 10 dB above threshold of IC neurons mainly was facilitation, but, which on maximum spike of IC neurons mainly was inhibition. Furthermore,it can be seen that changing of the types of latency - intensity function on noise masking was obvious, but which of rate- intensity function on contrary.
