中文摘要：

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。

英文摘要：

In natural acoustical environments, most biologically related sounds containing frequency-modulated （FM） components repeat over periods of time. They are often in rapid sequence rather than in temporal isolation. Few studies examined the neuronal response patterns evoked by FM stimuli at different presentation rates （PR）. In the present investigation, by using normal electrophysiological technique, we specifically studied the temporal features of response of the inferior collicular （IC） neurons to FM sweeps with different modulation ranges （MR） in conditions of distinct PR in mouse. The results showed that most of the recorded neurons responded best to narrower MRs （narrow-pass, up-sweep： 60.00%, 54/90; down-sweep： 63.33%, 57/90）, while a small fraction of neurons displayed other patterns such as band-pass （up-sweep, 16.67%, 15/90; down-sweep, 18.89%, 17/90）, all-pass （up- sweep, 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 the discharge rate and duration of recorded neurons decreased but the latency lengthened with increase in PR, when different PRs from 0.5/s to 10/s of FM sound were used. The percentage of total directional selective neurons, up-directional selective neurons, and down- directional selective neurons changed with the variation of PR or MR. These results indicate that temporal features of mouse midbrain neurons responding to FM sweeps are co-shaped by the MR and PR. Possible mechanisms underlying may be related to spectral and temporal integration of the FM sound by the IC neurons.