Yamada Yoshiaki, Yamamura Kensuke, Inoue Makoto
Division of Oral Physiology, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-dori, Niigata 951-8514, Japan.
Respir Physiol Neurobiol. 2005 Jul 28;147(2-3):177-89. doi: 10.1016/j.resp.2005.02.017. Epub 2005 Apr 19.
Mastication is the first stage of digestion and involves several motor processes such as food intake, intra-oral food transport, bolus formation and chewing in its broad sense. These complicated motor functions can be accomplished by the well-coordinated activities in various cranial motoneurons innervating the jaw, hyoid, tongue and facial muscles. The brainstem masticatory central pattern generator (CPG) plays a crucial role in generating basic activity patterns of these cranial motoneuron groups. However, descending inputs from higher brain (e.g., cerebral cortex) and mastication-generated peripheral sensory inputs also play important roles in modulating the activity pattern of each motoneuron so that the final motor outputs fit the environmental demand. In this review, we focus on the coordination of the trigeminal, facial and hypoglossal motoneurons during mastication. We first summarize findings showing the activity patterns of muscles innervated by these motoneurons during natural mastication, and then discuss the possible neural mechanisms underlying their coordinated activities during mastication.
咀嚼是消化的第一阶段，涉及多个运动过程，如食物摄取、口腔内食物转运、食团形成以及广义上的咀嚼。这些复杂的运动功能可通过支配颌骨、舌骨、舌头和面部肌肉的各种颅运动神经元的协调活动来完成。脑干咀嚼中枢模式发生器（CPG）在产生这些颅运动神经元群的基本活动模式中起着关键作用。然而，来自高级脑（如大脑皮层）的下行输入以及咀嚼产生的外周感觉输入在调节每个运动神经元的活动模式方面也发挥着重要作用，以便最终的运动输出符合环境需求。在这篇综述中，我们重点关注咀嚼过程中三叉神经、面神经和舌下神经运动神经元的协调。我们首先总结在自然咀嚼过程中这些运动神经元所支配肌肉的活动模式的研究发现，然后讨论咀嚼过程中其协调活动背后可能的神经机制。
