DIRECTIONAL HEARING IN THE GRASSFROG (RANA-TEMPORARIA L) .2. ACOUSTICS AND MODELING OF THE AUDITORY PERIPHERY
DIRECTIONAL HEARING IN THE GRASSFROG (RANA-TEMPORARIA L) .2. ACOUSTICS AND MODELING OF THE AUDITORY PERIPHERY
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DOI：
10.1016/0378-5955(86)90043-2
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发表时间：
1986-01-01
期刊：
影响因子：
2.8
通讯作者：
JOHANNESMA, PIM
中科院分区：
文献类型：
--
作者：
AERTSEN, AMHJ;VLAMING, MSMG;JOHANNESMA, PIM
在早期的论文（Vlaming 等，1984）中，我们报道了草蛙鼓膜振动特征的光学测量（激光多普勒干涉测量法）。在本文中，这些测量扩展到包括有关青蛙听力中口腔功能作用的声学测量。根据这些测量结果，开发了青蛙声学外围模型，该模型由三个耦合线性振荡器和三个声音入口组成，并进行了数学分析，以给出各种相关的传递函数。该模型有六个参数，所有这些参数都可以根据可用的实验数据进行估计。对于高达约 1500 Hz 的频率，该模型充分描述了实验数据，包括我们自己的和早期的、文献中看似相互矛盾的数据。对于较高的频率，可能会由于膜的不均匀振动而出现偏差。该模型用于评估青蛙在自由场刺激下的单耳方向敏感性。本质上，它充当组合压力梯度接收器，具有高度依赖于频率的方向灵敏度。通过改变口腔的共振特性可以极大地调节鼓膜的方向敏感性，而不影响固有的膜特性。从理论上讲，这使得青蛙可以通过主动调节其口腔的体积来操纵其方向敏感性。为了解释与低频听觉神经纤维已知特性的差异，模型中包含了额外的鼓室外通道。扩展模型（可能涉及岛盖复合体的第二通道）为鼓膜运动和听觉神经活动的现有数据提供了良好的定量拟合。最后，该模型能够模拟空间中的（移动）声源，同时通过闭合耦合器刺激青蛙。
In an earlier paper (Vlaming et al., 1984) we reported on optical measurements (laser-doppler interferometry) of the vibrations characteristics of the grassfrog''s tympanic membrane. In the present paper these measurements were extended to include acoustic measurements concerning the functional role of the mouth cavity in frog hearing. Based on these measurements a model of the frog''s acoustic periphery, consisting of three coupled linear oscillators with three entrance ports for sound, was developed and analyzed mathematically to give the various relevant transfer functions. The model is characterized by six parameters, all of which could be estimated from the available experimental data. For frequencies up to some 1500 Hz the model adequately describes the experimental data, both our own and earlier, seemingly conflicting data in the literature. For higher frequencies deviations occur, possibly due to nonuniform vibrations of the membranes. The model was used to evaluate the monaural directional sensitivity of the frog under free-field stimulation. Essentially it behaves as a combined pressure-gradient receiver, with highly frequency-dependent directional sensitivity. Directional sensitivity of the tympanic membrane could be modulated drastically by changing the resonance properties of the mouth cavity, without affecting the intrinsic membrane properties. This, theoretically, allows the frog to manipulate its direction sensitivity by actively tuning the volume of its mouth cavity. In order to account for discrepancies with known properties of low-frequency auditory nerve fibers an additional, extra-tympanic channel was included into the model. The extended model, the second-channel possibly involving the opercularis complex, provides a good quantitative fit to the available data on tympanic membrane movement as well as auditory nerve activity. Finally, the model enables to simulate a (moving) sound source in space, while stimulating the frog via closed couplers.