Wild J M
Department of Anatomy, School of Medicine, University of Auckland, New Zealand.
Eur J Morphol. 1997 Oct;35(4):303-25. doi: 10.1076/ejom.35.4.303.13077.
In birds, as in humans, vocal control involves the intricate coordination of three major groups of muscles, namely, those of the vocal organ, the respiratory apparatus, and the vocal tract, including the jaw and tongue. The neural pathways involved in the control of each of these groups of muscles are described for songbirds and compared with those in non-oscine birds and mammals. The pathway in songbirds that controls the syrinx, the bird's vocal organ, originates in the telencephalon and projects via the occipito-mesencephalic tract directly upon vocal motoneurons in the medulla. Activity in this pathway configures the syrinx into phonatory positions for the production of species typical vocalizations. Another component of this pathway mediates control of respiration during vocalization, since it projects upon both expiratory and inspiratory groups of premotor neurons in the ventrolateral medulla, as well as upon several other nuclei en route. This pathway appears to be primarily involved with the control of the temporal pattern of song, but is also importantly involved in the control of vocal intensity, mediated via air sac pressure. There are extensive interconnections between the vocal and respiratory pathways, especially at brainstem levels, and it may be these that ensure the necessary temporal coordination of syringeal and respiratory activity. The pathway mediating control of the jaw appears to be different from those mediating control of the syrinx and respiratory muscles. It originates in a different part of the telencephalon and projects upon premotor neurons in the medulla that, on preliminary analysis, appear to be separate from those projecting upon the syringeal motor nucleus. The separateness of this pathway may reflect the imperfect correlation of jaw movements with the dynamic and acoustic features of song. The brainstem pathways mediating control of vocalization and respiration in songbirds have distinct similarities to those in non-oscine birds and in mammals such as cats and monkeys. However, songbirds and parrots, like humans, but unlike other non-songbirds, have developed a special telencephalic vocal control system for the production of learned vocalizations.
与人类一样，鸟类的发声控制涉及三大肌群的复杂协调，即发声器官、呼吸器官以及包括颌骨和舌头在内的声道的肌肉。本文描述了鸣禽中控制这些肌群的神经通路，并与非鸣禽和哺乳动物的神经通路进行了比较。鸣禽中控制鸣管（鸟类的发声器官）的通路起源于端脑，经枕中脑束直接投射到延髓中的发声运动神经元。该通路中的活动将鸣管配置到发声位置，以产生特定物种的典型发声。该通路的另一个组成部分在发声过程中介导呼吸控制，因为它投射到延髓腹外侧的呼气和吸气前运动神经元群，以及沿途的其他几个核团。这条通路似乎主要参与歌曲时间模式的控制，但也重要地参与通过气囊压力介导的发声强度控制。发声和呼吸通路之间存在广泛的相互连接，尤其是在脑干水平，可能正是这些连接确保了鸣管和呼吸活动必要的时间协调。介导颌骨控制的通路似乎与介导鸣管和呼吸肌控制的通路不同。它起源于端脑的不同部位，并投射到延髓中的前运动神经元，初步分析表明，这些神经元似乎与投射到鸣管运动核的神经元是分开的。这条通路的独立性可能反映了颌骨运动与歌曲的动态和声学特征之间的不完全相关性。鸣禽中介导发声和呼吸控制的脑干通路与非鸣禽以及猫和猴子等哺乳动物的脑干通路有明显的相似之处。然而，与人类一样，但与其他非鸣禽不同，鸣禽和鹦鹉已经发展出一种特殊的端脑发声控制系统，用于产生习得的发声。
