Mechanical responses to two-tone distortion products in the apical and basal turns of the mammalian cochlea
Mechanical responses to two-tone distortion products in the apical and basal turns of the mammalian cochlea
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DOI：
10.1152/jn.1997.78.1.261
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发表时间：
1997-07-01
影响因子：
2.5
通讯作者：
Rhode, WS
中科院分区：
文献类型：
--
作者：
Cooper, NP;Rhode, WS
从灰鼠耳蜗的顶转、豚鼠耳蜗的底转和豚鼠耳蜗的钩区的耳蜗分区记录对单音调和双音调声刺激的机械响应。研究部位的最敏感或“最佳”频率（BF）分别类似于500 Hz、17 kHz和30 kHz。在每个部位表征对三次差音（CDT）2F（1）- F-2（其中F-1和F-2是主要刺激的频率）的反应。对二次差音（QDT）的反应，F-2 - F-1，也在顶转准备中进行了表征（QDT反应太小，无法在基底耳蜗中测量）。观察到的反应BF QDT和CDTs和BF CDTs在每个网站出现在许多方面相似;的相对幅度的响应是最高的低至中等声压级（SPL），例如，和绝对幅度增长非单调增加的水平，无论是主要的（L-1或L-2）单独。CDT和QDT响应的峰值有效水平也相似，约为-20 dB re L-1和/或L-2。然而，在其他方面，对CDT和QDT以及对BF CDT的反应在每个站点表现得非常不同。例如，在低到中等SPL时，大多数CDT相位导联随着L-1或L-2的增加而减少，而大多数QDT相位导联随着L-1的增加而增加，并且随着L-2变化不大。大多数CDT响应也随着等水平的原色单调变化（即，当L-1 = L-2时），而大多数QDT响应非单调变化。当F-1和F-2变化时，不同的反应也以不同的方式变化。在很宽的F-1/F-2范围内（F-1 = 1-12 kHz）观察到心尖翻转QDT反应，但通常在< 2-4 kHz的刺激下最大。只有当频率比F-2/F-1增加到超过1.4-1.5时，心尖转向CDT水平才下降（以类似于40-80 dB/倍频程的速率）。在基底转向和钩状区，CDT水平非单调地依赖于F-2/F-1，最终下降率类似于200 dB/倍频程。随着SPL的增加，CDT的最佳频率比从（F-2 <1.1F-1）增加到（F-2约为1.2F-1），但在钩区稳定在约1.05的F-2/F-1。在耳蜗的所有三个区域中，CDT相位导联倾向于随着F-2/F-1的增加而增加，特别是在低至中等SPL处。这些发现与之前对耳蜗力学、生理学和心理物理学的研究有关。
Mechanical responses to one- and two-tone acoustic stimuli were recorded from the cochlear partition in the apical turn of the chinchilla cochlea, the basal turn of the guinea pig cochlea, and the hook region of the guinea pig cochlea. The most sensitive or ''best'' frequencies (BFs) for the sites studied were similar to 500 Hz, 17 kHz, and 30 kHz, respectively. Responses to the cubic difference tone (CDT), 2F(1) - F-2 (where F-1 and F-2 are the frequencies of the primary stimuli),were characterized at each site. Responses to the quadratic difference tone (QDT), F-2 - F-1, were also characterized in the apical turn preparations (QDT responses were too small to measure in the basal cochlea). The observed responses to BF QDTs and CDTs and to BF CDTs at each site appeared similar in many ways; the relative magnitudes of the responses were highest at low-to-moderate sound pressure levels (SPLs), for example, and the absolute magnitudes grew nonmonotonically with increases in the level of either primary (L-1 or L-2) alone. The peak effective levels of the CDT and QDT responses were also similar, at around -20 dB re L-1 and/or L-2. In other respects, however, the responses to CDTs and QDTs and to BF CDTs at each site behaved quite differently. At low to-moderate SPLs, for example, most CDT phase leads decreased with increases in either L-1 or L-2, whereas most QDT phase leads increased with increasing L-1 and varied little with L-2. Most CDT responses also varied monotonically with equal-level primaries (i.e., when L-1 = L-2), whereas most QDT responses varied nonmonotonically. Different responses also varied in different ways when F-1 and F-2 were varied. Apical turn QDT responses were observed over a very wide F-1/F-2 range (F-1 = 1-12 kHz), but were usually largest for stimuli < 2-4 kHz. Apical turn CDT levels decreased (at rates of similar to 40-80 dB/octave) only when the frequency ratio F-2/F-1 increased beyond similar to 1.4-1.5. In the basal turn and hook regions, the CDT levels depended non-monotonically on F-2/F-1, with the eventual rates of decrease being similar to 200 dB/octave. Optimal frequency ratios for the CDT increased from (F-2 < 1.1 F-1) to (F-2 approximate to 1.2 F-1) with increasing SPL in the basal turn, but were stable at around F-2/F-1 approximate to 1.05 in the hook region. CDT phase leads tended to increase with increasing F-2/F-1 in all three regions of the cochlea, particularly at low-to-moderate SPLs. These findings are discussed in relation to previous studies of cochlear mechanics, physiology, and psychophysics.