Versnel H, Prijs V F, Schoonhoven R
ENT Department, University Hospital, Leiden, The Netherlands.
Hear Res. 1992 May;59(2):157-70. doi: 10.1016/0378-5955(92)90112-z.
Unit responses (URs) of eighth-nerve fibres have been determined at the round window by spike-triggered averaging in both normal and pathological guinea pig cochleas. The pathology was mainly noise-induced damage. The URs have been analysed with respect to their dependence on the fibre's threshold, characteristic frequency (CF) and spontaneous rate (SR). The results from normal cochleas confirmed earlier data (Prijs, 1986): the UR has a diphasic waveform and the amplitude of its negative first peak is about 0.1 microV. From the six parameters (amplitude, latency, and width of the two peaks) by which the UR was described only the amplitude of the positive peak showed a significant variation with CF: a small decrease with increasing CF (CF-range 0.1 to 20 kHz). This finding may possibly be caused by oscillations in the spike-triggered average for low CFs. URs for most low- and medium-SR fibres were found to be large (greater than 0.3 microV). However, this result is interpreted as an artefact caused by synchrony of fibre spontaneous activity. In damaged cochleas only slight changes of the UR were found: the waveform duration became significantly shorter and on some occasions the positive peak increased in amplitude, but latency and amplitude of the negative component of the UR remained unchanged.
通过对正常和病理状态下豚鼠耳蜗圆窗处的听神经纤维进行触发峰平均法，测定了单位反应（URs）。病理状态主要是噪声诱发的损伤。已根据URs对纤维阈值、特征频率（CF）和自发放电率（SR）的依赖性进行了分析。正常耳蜗的结果证实了早期的数据（普里斯，1986年）：UR具有双相波形，其负向第一峰的幅度约为0.1微伏。在描述UR的六个参数（两个峰的幅度、潜伏期和宽度）中，只有正向峰的幅度随CF有显著变化：随CF增加（CF范围为0.1至20千赫）略有下降。这一发现可能是由于低CF时触发峰平均中的振荡所致。发现大多数低SR和中SR纤维的URs较大（大于0.3微伏）。然而，这一结果被解释为由纤维自发放电活动同步引起的假象。在受损耳蜗中，仅发现UR有轻微变化：波形持续时间显著缩短，在某些情况下正向峰幅度增加，但UR负向成分的潜伏期和幅度保持不变。
