胭脂鱼听觉阈值研究

Auditory thresholds of Chinese sucker Myxocyprinus asiaticus

利用听性脑干反应技术研究了胭脂鱼（Myxocyprinus asiaticus）的听觉阈值。通过插入皮下的电极记录了10尾胭脂鱼的短纯音听觉诱发电位。结果显示,在系统最大声强下,胭脂鱼的听频范围为100~5 000 Hz,其中对100～2 000 Hz的声音敏感度较高,最敏感的频率为800 Hz,听觉阈值约为69.8 dB。随着声强的减小,胭脂鱼的听性脑干反应波形最大,振幅减小,潜伏期延长。将10尾胭脂鱼的阈值平均,得到了胭脂鱼的听性脑干反应听力图。胭脂鱼的听力图呈＂U＂形,属于典型的动物听力曲线。研究胭脂鱼的听觉阈值对胭脂鱼物种保护具有重要意义,同时可为评估噪声对胭脂鱼的影响提供数据支持。

Auditory brainstem response （ABR） technic has been widely used to study hearing ability in fishes. In contrast to the behavior and traditional electrophysiology methods, this approach provides the following advantages： （1） there is no harm to the animals because it is non-invasive; （2） hearing sensitivity in untrained fish can be determined rapidly; （3） individuals are reusable. Using ABR approach, auditory evoked potentials of 10 Chinese suckers Myxocyprinus asiaticus were recorded using two subcutaneous electrodes. We found that the fish can detected tone bursts from 100 to 5 000 Hz. The results showed the best hearing between 100 to 2 000 Hz, and the lowest threshold was 69.8 dB at 800 Hz. There was a positive correlation between the amplitude of the ABR waveform and the stimulus intensity, while there was a negative correlation between latency and stimulus intensity. Threshold values from 10 individuals were averaged to produce audiogram. Similarly to the most audiograms, it is a U-shape with thresholds increasing at both high and low frequency limits of hearing. The results have an important significance in protecting Chinese sucker and providing supporting data for access the effect of noise on fishes.