中文摘要：

目的观察正常豚鼠下丘的电生理特性,为进一步研究噪声暴露后下丘的电生理改变奠定基础。方法采用钨丝电极细胞外单个神经元记录,刺激信号和神经元原始信号均经过Tucker-Davis Technologies（TDT）系统转换。刺激序列主要包括：（1）扫频序列,测定下丘神经元的特征频率和最小阈值;（2）重复刺激序列,测定神经元的发放类型;（3）强度变化刺激,测定神经元的强度-发放率、强度-潜伏期曲线。数据经MATLAB软件分析。结果 （1）大部分频率反应面积图（frequency response area,FRA）为V-shape型（84.89%）,其余为non-V-shape型。（2）沿背腹轴方向,随着深度的增加,特征频率（characteristic frequency,CF）呈阶梯式增加。特征频率与其阈值（min-imum threshold,MT）的函数关系呈U形即低频和高频部分阈值较高。特征频率的阈值由浅到深总体表现为＂V＂型。（3）反应率-强度函数（rate-intensity function,RIF）有五型：a.u1型;b.u2型;c.u3型;d.ud型;e.N型。（4）刺激后时间直方图（post-stimulus time histogram,PSTH）有五型：a.抑制型;b.瞬态型;c.长潜伏期型;d.暂停/发放型;e.发放型。结论 （1）豚鼠的下丘音频定位图与大鼠和猫基本相似,即沿下丘背腹轴,大部分的特征频率逐渐递增,呈薄片、叠瓦状分布。（2）反应率-强度函数（RIF）和刺激后时间直方图（PSTH）也是体现神经元反应特性的重要指标,不同的RIF和PSTH分别代表不同类型的神经元。

英文摘要：

Objective To characterize electrophysiological features of the inferior colliculus in normal guinea pigs for future electrophysiological studies of the inferior colliculus in response to noise exposure. Methods Electrical activities in single neurons were recorded extracellularly using tungsten electrodes. Stimulus and recorded signals were processed using a Tucker -Davis Technologies system. Stimulation included： 1） frequency sweeping to determine characteristic frequency （CF） and minimal threshold （MT） of a neuron; 2） repeat stimulation to determine the neuron＇s discharge patterns; and 3） intensity-varying stimulation to determine the neuron＇s intensity-discharge rate function and intensity-latency function. The MATLAB software was used for data analysis. Results 1） The frequency response area （FRA） was V-shaped in most neurons tested（84.89%）. 2） Along the dorso-ventral axis, the CF increased in steps as the depth increased. The CF/MT function was U-shaped, showing relatively high thresholds at high and low frequencies. The relation between the depth and threshold at the CF was V-shaped. 3） The response rate-intensity function （RIF） could be characterized as： u1, u2, u3, ud and N types. 4） The post-stimulation time histogram （PSTH） were characterized as inhibitory, transient, long delayed, pausing / discharging and discharging. Conclusion 1） The frequency map in the guinea pig is similar to that in rats and cats, i.e. the CF gradually increases along the dorso-ventral axis with a distribution in thin layers. 2） The RIF and PSTH are important features in neuron responses, representing different types of neurons.