Müller Rolf, Lu Hongwang, Buck John R
School of Physics and Microelectronics, Shandong University, Hongjia Lou 5, 250100 Jinan, China.
Phys Rev Lett. 2008 Mar 14;100(10):108701. doi: 10.1103/PhysRevLett.100.108701.
Sound diffraction by the mammalian ear generates source-direction information. We have obtained an immediate quantification of this information from numerical predictions. We demonstrate the power of our approach by showing that a small flap in a bat's pinna generates useful information over a large set of directions in a central band of frequencies: presence of the flap more than doubled the solid angle with direction information above a given threshold. From the workings of the employed information measure, the Cramér-Rao lower bound, we can explain how physical shape is linked to sensory information via a strong sidelobe with frequency-dependent orientation in the directivity pattern. This method could be applied to any other mammal species with pinnae to quantify the relative importance of pinna structures' contributions to directional information and to facilitate interspecific comparisons of pinna directivity patterns.
哺乳动物耳朵的声音衍射会产生声源方向信息。我们已从数值预测中直接量化了此信息。我们通过表明蝙蝠耳廓中的一个小皮瓣在中心频率带的大量方向上产生有用信息，展示了我们方法的强大之处：皮瓣的存在使具有高于给定阈值方向信息的立体角增加了一倍多。从所采用的信息度量（克拉美 - 罗下界）的原理出发，我们可以解释物理形状是如何通过指向性图案中具有频率依赖性取向的强旁瓣与感官信息相联系的。该方法可应用于任何其他具有耳廓的哺乳动物物种，以量化耳廓结构对方向信息贡献的相对重要性，并便于对耳廓指向性图案进行种间比较。
