目的 探究神经元对刺激声音听觉响应的发放模式本身是否影响刺激特异性适应(SSA)特性.方法 以清醒小鼠的下丘神经元为研究对象,采用玻璃微电极贴附式记录下丘神经元在由两个不同频率(f1和f2)的纯音按不同重复概率随机组成的声音刺激序列下的听觉响应.并计算两个纯音总体或局部在标准刺激条件下的响应s(f1)与s(f2)即f1、f2作为标准声音时引起的神经元响应和在偏差刺激条件下的响应d(f1)与d(f2)即f1、f2作为偏差声音时引起的神经元响应.随后计算3个重要指标:(1)两个纯音的听觉响应强度差异指数(FDI);(2)频率特异的SSA指数(SI);(3)SSA指数(CSI),最后对数据进行统计分析.结果 FDI较大神经元的CSI显著高于FDI较小的神经元(P<0.05),并且响应类型为初级响应型的神经元在不同时间段的SSA表现不同,相对于起始部分,持续部分的SSA显著地增高(P<0.05).结论 刺激声音的听觉响应模式也是SSA的重要影响因素.%Objective To explore whether the pattern of neuron's auditory response to a sound stimulus affects the characteristics of stimulus-specific adaptation (SSA) in awake mice. Methods The auditory responses of the neurons in the inferior colliculus to sound stimuli were recorded using microelectrodes in awake mice. The sequence of sound stimuli consisted of random combinations of pure tones of two different frequencies (f1 and f2) with different repetition rates. The auditory responses of the neurons to standard and deviant stimuli were calculated, namely s(f2)/s(f2) and d(f1)/d(f2), respectively. Three indexes of the responses were also calculated, including the firing difference index (FDI), frequency-specific index (SI), and common SSA index(CSI). Results The CSI of neurons with a greater FDI was significantly higher than that of neurons with a smaller FDI (P<0.05). The primary-like neurons showed different characteristics of SSAs in different time periods; SSA was significantly increased in the phase of sustained response compared with that at the onset of response (P<0.05). Conclusion The auditory response pattern to sound stimuli is also an important factor that affect SSA of inferior colliculus neurons in awake mice.
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