Syka J, Popelár J
Hear Res. 1980 Oct;3(3):205-13. doi: 10.1016/0378-5955(80)90047-7.
Auditory thresholds were assessed in three guinea pigs with a conditioning procedure based on the positive reinforcement paradigm. Thereafter, the guinea pigs were exposed for 5 days to third octave band noise centred at 2 kHz at 100 dB SPL. Thresholds at 0.5, 2 and 4 kHz were controlled during the exposure and up to 120 days after exposure. After 6 h of exposure, the threshold shift at 4 kHz reached 40 dB and increased slowly to 45 dB by the fifth day. The quasi-asymptotic shift was less expressed at 2 kHz, where the initial threshold shift amounted to 20 dB and rose to 40 dB by the fifth day. Thresholds recovered in the time course of 5 days after exposure and a significant permanent threshold shift was present 120 days after exposure. It amounted to 35 dB at 4 kHz and to 20 dB at 2 kHz. Auditory thresholds were dependent upon the duration of the stimulus: the decrease in duration of a tone from 200 ms to 2 ms caused a rise in threshold of about 10 dB before as well as after the exposure. The effects of prolonged noise exposure upon guinea pigs are similar to those found in chinchillas with the exception of the permanent threshold shift, which is more marked in guinea pigs.
采用基于正强化范式的条件反射程序，对三只豚鼠的听觉阈值进行了评估。此后，将豚鼠暴露于以2kHz为中心、声压级为100dB SPL的1/3倍频程带噪声中，持续5天。在暴露期间以及暴露后长达120天内，对0.5、2和4kHz的阈值进行监测。暴露6小时后，4kHz处的阈值偏移达到40dB，并在第5天缓慢增加至45dB。2kHz处的准渐近偏移表现较弱，初始阈值偏移为20dB，到第5天升至40dB。暴露后5天内阈值恢复，暴露120天后出现显著的永久性阈值偏移。4kHz处为35dB，2kHz处为20dB。听觉阈值取决于刺激的持续时间：在暴露前后，音调持续时间从200ms减少到2ms，都会导致阈值升高约10dB。除了永久性阈值偏移在豚鼠中更为明显外，长时间噪声暴露对豚鼠的影响与在栗鼠中发现的影响相似。
