Sensorineural hearing loss (SNHL) causes an overall deficit in binaural hearing, including the abilities to localize sound sources, discriminate interaural time and level differences (ITDs and ILDs, respectively), and utilize binaural cues to aid signal detection and comprehension in noisy environments. Few studies have examined the effect of SNHL on binaural coding in the central auditory system, and those that have focused on age-related hearing loss. We induced hearing loss in male and female Dutch-belted rabbits via noise overexposure and compared unanesthetized, single-unit responses of their inferior colliculi (HL neurons) to those of unexposed rabbits. Sound-level thresholds of HL neurons to diotic noise were elevated by 75 dB, on average. Sensitivity of firing rates of HL neurons to the azimuth of a broadband noise stimulus was reduced, on average, but was confounded by differences in sound level with respect to detection threshold between groups. We independently manipulated ITD and ILD in virtual acoustic space and found directional sensitivity in binaurally sensitive HL neurons was entirely due to ILD sensitivity and no different than that for unexposed rabbits. However, ITD sensitivity was completely absent in binaurally sensitive HL neurons for noise stimuli both in virtual acoustic space and with ITDs extending to ±3 ms. HL neurons also had weaker spike-timing precision and slightly increased spontaneous rates. Overall, ILD sensitivity was uncompromised whereas ITD sensitivity was completely lost, implying a specific inability to utilize information in the timing or correlation of acoustic noise waveforms between the two ears following severe SNHL.

中文翻译：

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噪声引起的听力损失后未调制噪声刺激的耳间时间差的神经敏感性的特定损失。

感音神经性听力损失 (SNHL) 导致双耳听力的整体缺陷，包括定位声源、区分耳间时间和电平差异（分别为 ITD 和 ILD）的能力，以及利用双耳线索来帮助在嘈杂环境中检测和理解信号的能力。很少有研究检查 SNHL 对中央听觉系统双耳编码的影响，以及那些关注与年龄相关的听力损失的研究。我们通过噪音过度暴露诱导雄性和雌性荷兰带兔的听力损失，并将它们的下丘（HL 神经元）的未麻醉的单单位反应与未暴露的兔子的反应进行比较。HL 神经元对双耳噪声的声级阈值平均提高了 75 dB。HL 神经元放电率对宽带噪声刺激方位角的敏感性降低，平均而言，但被组间检测阈值方面的声级差异所混淆。我们在虚拟声学空间中独立操纵 ITD 和 ILD，发现双耳敏感的 HL 神经元的方向敏感性完全归因于 ILD 敏感性，与未暴露的兔子没有区别。然而，双耳敏感的 HL 神经元对于虚拟声学空间中的噪声刺激完全不存在 ITD 敏感性，并且 ITD 扩展到 ±3 ms。HL 神经元的尖峰计时精度也较弱，自发率略有增加。总体而言，ILD 灵敏度未受影响，而 ITD 灵敏度完全丧失，这意味着在严重 SNHL 后，特别无法利用两耳之间声学噪声波形的时间或相关性信息。但被组间检测阈值方面的声级差异所混淆。我们在虚拟声学空间中独立操纵 ITD 和 ILD，发现双耳敏感的 HL 神经元的方向敏感性完全归因于 ILD 敏感性，与未暴露的兔子没有区别。然而，双耳敏感的 HL 神经元对于虚拟声学空间中的噪声刺激完全不存在 ITD 敏感性，并且 ITD 扩展到 ±3 ms。HL 神经元的尖峰计时精度也较弱，自发率略有增加。总体而言，ILD 灵敏度未受影响，而 ITD 灵敏度完全丧失，这意味着在严重 SNHL 后，特别无法利用两耳之间声学噪声波形的时间或相关性信息。但被组间检测阈值方面的声级差异所混淆。我们在虚拟声学空间中独立操纵 ITD 和 ILD，发现双耳敏感 HL 神经元的方向敏感性完全归因于 ILD 敏感性，与未暴露的兔子没有区别。然而，双耳敏感的 HL 神经元对于虚拟声学空间中的噪声刺激完全不存在 ITD 敏感性，并且 ITD 扩展到 ±3 ms。HL 神经元的尖峰计时精度也较弱，自发率略有增加。总体而言，ILD 灵敏度未受影响，而 ITD 灵敏度完全丧失，这意味着在严重 SNHL 后，特别无法利用两耳之间声学噪声波形的时间或相关性信息。