中文摘要：

基于我们先前的研究,主要探讨了小鼠下丘神经元声反应伏期的年龄相关性改变。自由声场条件下,声刺激为特征频率的短纯音（40 ms）,呈现率为0.5-20 Hz共8种。结果显示,幼年鼠和成年鼠中,潜伏期随呈现率升高而单调递增的神经元分别点62.8%（22/35）和66.7%（22/23）,而老年鼠中只占33.3%（11/33）,但非单调比则达66.7%（22/23）。我们的初步结果提示,老年性听力低下可能与大声负载条件下听中枢神经元的时相表征稳定性下降有关。

英文摘要：

Based on the previous study in our lab, this research concentrates on whether and how the acoustical response latency of inferior colliculus （IC） neurons of mouse in different ages changes. The tones with duration of 40 ms at characteristic frequency （CF） of recorded neurons were presented to Pentobarbital sodium anesthetized mice （Mus musculus, Km） at different rates （PR, ranged from 0.5 - 20 Hz） under free field stimulation conditions. The results show that in young mouse and adult mouse, the latency of the majority neurons （62.8%, 22/35 and 66.7%, 22/33, respectively） monotonically prolonged with the PR increasing. On the contrary, in old mouse, latency of most of the neurons （66.7%, 22/33） varied non-monotonically, indicating that latency in old mouse fluctuated much heavier than in young and adult mouse. Our preliminary data suggest presbycusis in human might be related with stability decrease in spectral representation of central auditory neurons under stimulating condition of large sound loads.