A new mechanism of sound generation in songbirds
A new mechanism of sound generation in songbirds
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DOI：
10.1073/pnas.94.26.14787
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发表时间：
1997-12-23
影响因子：
11.1
通讯作者：
Larsen, ON
中科院分区：
文献类型：
--
作者：
Goller, F;Larsen, ON
我们目前对鸣禽鸣管发声机制的理解是基于间接证据和理论处理。经典的鸟类发声模型假定内侧鼓膜（MTM）是主要的发声器。我们测试了MTM在发声中的作用，并通过内窥镜拍摄更直接地研究了鸣禽鸣管。在我们通过手术使MTM失去作为振动源的能力后，斑胸草雀和红雀不仅能够发声，而且能唱出几乎正常的歌曲。这一结果清楚地表明，MTM不是主要的声源。内窥镜图像的完整鸣禽鸣管在自发和脑刺激引起的发声说明发声前的动态reconfiguration和建议一个不同的模型的声音产生。发声是由嘴部的运动和鸣管的伸展发起的。同时，通过两个软组织块（内侧阴唇和外侧阴唇）进入支气管腔，使空洞闭合。声音的产生总是伴随着两个阴唇的振动运动，这表明这些振动可能是声源。然而，由于成像系统的时间分辨率低，唇振动的频率和相位不能相对于所产生的声音进行评估。尽管如此，与之前的模型相反，这些观察结果表明，两个阴唇都有助于孔径控制，并强烈表明它们作为主要声音发生器发挥着重要作用。
Our current understanding of the sound-generating mechanism in the songbird vocal organ, the syrinx, is based on indirect evidence and theoretical treatments. The classical avian model of sound production postulates that the medial tympaniform membranes (MTM) are the principal sound generators, We tested the role of the MTM in sound generation and studied the songbird syrinx more directly by filming it endoscopically. After we surgically incapacitated the MTM as a vibratory source, zebra finches and cardinals were not only able to vocalize, but sang nearly normal song. This result shows clearly that the MTM are not the principal sound source. The endoscopic images of the intact songbird syrinx during spontaneous and brain stimulation-induced vocalizations illustrate the dynamics of syringeal reconfiguration before phonation and suggest a different model for sound production. Phonation is initiated by rostrad movement and stretching of the syrinx. At the same time, the syrinx is closed through movement of two soft tissue masses, the medial and lateral labia, into the bronchial lumen. Sound production always is accompanied by vibratory motions of both labia, indicating that these vibrations may be the sound source. However, because of the low temporal resolution of the imaging system, the frequency and phase of labial vibrations could not be assessed in relation to that of the generated sound. NevertheIess, in contrast to the previous model, these observations show that both labia contribute to aperture control and strongly suggest that they play an important role as principal sound generators.