Radziwon Kelly, Holfoth David, Lindner Julia, Kaier-Green Zoe, Bowler Rachael, Urban Maxwell, Salvi Richard
Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, SUNY at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA.
Center for Hearing & Deafness, Department of Communicative Disorders and Sciences, SUNY at Buffalo, 137 Cary Hall, Buffalo, NY, 14214, USA.
Hear Res. 2017 Jul;350:133-138. doi: 10.1016/j.heares.2017.04.004. Epub 2017 Apr 27.
The use of auditory reaction time is a reliable measure of loudness perception in both animals and humans with reaction times (RT) decreasing with increasing stimulus intensity. Since abnormal loudness perception is a common feature of hyperacusis, a potentially debilitating auditory disorder in which moderate-intensity sounds are perceived as uncomfortable or painfully loud, we used RT measures to assess rats for salicylate-induced hyperacusis. A previous study using an operant conditioning RT procedure found that high-dose sodium salicylate (SS) induced hyperacusis-like behavior, i.e., faster than normal RTs to moderate and high level sounds, when rats were tested with broadband noise stimuli. However, it was not clear from that study if salicylate induces hyperacusis-like behavior in a dose- or frequency-dependent manner. Therefore, the goals of the current study were to determine how RT-intensity functions were altered by different doses of salicylate, and, using tone bursts, to determine if salicylate induces hyperacusis-like behavior across the entire frequency spectrum or only at certain frequencies. Similar to previous physiological studies, we began to see faster than normal RTs for sounds 60 dB SPL and greater with salicylate doses of 150 mg/kg and higher; indicating the rats were experiencing hyperacusis at high salicylate doses. In addition, high-dose salicylate significantly reduced RTs across all stimulus frequencies tested which suggests that a central neural excitability mechanism may be a potential driver of salicylate-induced changes in loudness perception and hyperacusis.
听觉反应时间的使用是衡量动物和人类响度感知的可靠指标,反应时间(RT)会随着刺激强度的增加而缩短。由于响度感知异常是听觉过敏的一个常见特征,听觉过敏是一种潜在的使人衰弱的听觉障碍,在此病症中,中等强度的声音会被感知为不舒服或异常响亮,我们使用反应时间测量来评估大鼠水杨酸盐诱导的听觉过敏。之前一项使用操作性条件反射反应时间程序的研究发现,当用宽带噪声刺激测试大鼠时,高剂量水杨酸钠(SS)会诱发类似听觉过敏的行为,即对中等和高强度声音的反应时间比正常情况更快。然而,从该研究中尚不清楚水杨酸盐是否以剂量或频率依赖的方式诱发类似听觉过敏的行为。因此,本研究的目的是确定不同剂量的水杨酸盐如何改变反应时间-强度函数,并且使用短纯音来确定水杨酸盐是否在整个频谱范围内诱发类似听觉过敏的行为,还是仅在某些频率上诱发。与之前的生理学研究类似,我们开始观察到,水杨酸盐剂量为150mg/kg及以上时,对于60dB SPL及更高强度的声音,大鼠的反应时间比正常情况更快;这表明高剂量水杨酸盐下大鼠出现了听觉过敏。此外,高剂量水杨酸盐显著缩短了所有测试刺激频率下的反应时间,这表明中枢神经兴奋性机制可能是水杨酸盐诱导的响度感知变化和听觉过敏的潜在驱动因素。