Amador Ana, Mindlin Gabriel B, Elemans Coen P H
Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
Instituto de Física Interdisciplinaria y Aplicada (INFINA - CONICET - UBA), Buenos Aires, Argentina.
Philos Trans R Soc Lond B Biol Sci. 2025 Apr 3;380(1923):20240007. doi: 10.1098/rstb.2024.0007.
Birds evolved a novel vocal organ, the syrinx, that exhibits a high anatomical diversity. In the few species investigated, the syrinx can contain up to three pairs of functional syringeal vocal folds, acting as independent sound sources, and eight pairs of muscles. This rich variety in vocal structures and motor control results in a wide range of nonlinear phenomena (NLPs) and interactions that are distinct to avian vocal physiology, with many fascinating mechanisms yet to be discovered. Here, we review the occurrence of classical signatures of nonlinear dynamics, such as NLPs, including frequency jumps and transitions to chaos in birds. However, birds employ several additional unique tricks and transitions of inherent nonlinear dynamical nature that further enrich their vocal dynamics and are relevant for understanding the motor control of their vocalizations. Particularly, saddle-node in limit cycle (SNILC) bifurcations can switch sounds from tonal to harmonically rich and change the physiological control of fundamental frequency. In mammalian phonation, these bifurcations are mostly explored in the context of register transitions but could be equally relevant to altering vocal fold dynamical behaviour. Due to their diverse anatomy compared to mammals, birds provide unique opportunities to explore rich nonlinear dynamics in vocal production.This article is part of the theme issue 'Nonlinear phenomena in vertebrate vocalizations: mechanisms and communicative functions'.
鸟类进化出了一种新型发声器官——鸣管，其具有高度的解剖学多样性。在已研究的少数物种中，鸣管可包含多达三对功能性鸣管声带，作为独立的声源，以及八对肌肉。这种发声结构和运动控制的丰富多样性导致了一系列广泛的非线性现象（NLPs）和相互作用，这些现象在鸟类发声生理学中是独特的，还有许多迷人的机制有待发现。在这里，我们回顾了非线性动力学经典特征的出现情况，例如鸟类中的NLPs，包括频率跳跃和向混沌的转变。然而，鸟类还采用了几种额外的、具有固有非线性动力学性质的独特技巧和转变，这些进一步丰富了它们的发声动力学，并且与理解它们发声的运动控制相关。特别是，极限环鞍结（SNILC）分岔可以将声音从音调丰富转变为谐波丰富，并改变基频的生理控制。在哺乳动物发声中，这些分岔大多是在声区转换的背景下进行研究的，但可能同样与改变声带动力学行为相关。与哺乳动物相比，由于鸟类具有多样的解剖结构，它们为探索发声产生中丰富的非线性动力学提供了独特的机会。本文是主题为“脊椎动物发声中的非线性现象：机制与交流功能”的一部分。
