Biophysics of directional hearing in the American alligator (Alligator mississippiensis)
Biophysics of directional hearing in the American alligator (Alligator mississippiensis)
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DOI：
10.1242/jeb.092866
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发表时间：
2014-04-01
影响因子：
2.8
通讯作者：
Tollin, Daniel J.
中科院分区：
文献类型：
--
作者：
Bierman, Hilary S.;Thornton, Jennifer L.;Tollin, Daniel J.
生理学和解剖学研究表明，短吻鳄对空间听觉有独特的适应能力。声音定位线索主要是通过头部对声波的过滤产生的。不同的脊椎动物谱系已经进化出外部和/或内部解剖学适应来增强这些线索，例如耳廓和耳间管。据推测，在短吻鳄中，方向性可以通过中耳腔的声学耦合来增强，从而导致压差接收器（PDR）机制。本文报道的实验通过证明（1）由动物的外部形态产生的声学空间线索不足以产生匹配生理敏感性的位置线索，（2）中耳之间存在连续通路以提供耦合的解剖学基础，（3）听觉脑干反应显示出一定的方向性，（4）鼓膜运动方向敏感。总之，这些数据支持PDR机制在鳄鱼中的作用，并进一步表明这种机制是一种共有的祖龙特征，很可能也存在于灭绝的恐龙中。
Physiological and anatomical studies have suggested that alligators have unique adaptations for spatial hearing. Sound localization cues are primarily generated by the filtering of sound waves by the head. Different vertebrate lineages have evolved external and/or internal anatomical adaptations to enhance these cues, such as pinnae and interaural canals. It has been hypothesized that in alligators, directionality may be enhanced via the acoustic coupling of middle ear cavities, resulting in a pressure difference receiver (PDR) mechanism. The experiments reported here support a role for a PDR mechanism in alligator sound localization by demonstrating that (1) acoustic space cues generated by the external morphology of the animal are not sufficient to generate location cues that match physiological sensitivity, (2) continuous pathways between the middle ears are present to provide an anatomical basis for coupling, (3) the auditory brainstem response shows some directionality, and (4) eardrum movement is directionally sensitive. Together, these data support the role of a PDR mechanism in crocodilians and further suggest this mechanism is a shared archosaur trait, most likely found also in the extinct dinosaurs.