Nakamura Y, Katakura N
Department of Physiology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
Neurosci Res. 1995 Aug;23(1):1-19.
Mastication is a typical rhythmical behavior in mammals. Like respiration, it is now generally accepted that the motor command for the basic pattern of rhythmical oral-facial movements is generated by a neuronal population in the brainstem (central pattern generator, CPG). The central pattern generation of rhythmical masticatory movements can be divided into three processes: (1) generation of the masticatory rhythm, (2) generation of a pattern of activities of the jaw, tongue and facial muscles, and (3) coordination of the activities of these muscles. There are several lines of evidence that the masticatory CPG is functionally subdivided into two neuronal groups: one for generation of the masticatory rhythm, giving the timing signal for rhythmical alternation of jaw closing and jaw opening (central rhythm generator, CRG), and the other for generation of the spatiotemporal pattern of activities of the jaw, tongue and facial muscles. This review will deal, first of all, with the localization of the CRG for rhythmical masticatory jaw movements, sources for its activation, and the premotor neurons mediating its output to the trigeminal motoneurons. Next, we will discuss the neurochemical basis for rhythmical trigeminal motoneurons activity as well as central masticatory rhythm generation. Finally, our recent attempt at induction of neural activities reflecting sucking movements (fictive sucking) in an in vitro preparation is presented.
咀嚼是哺乳动物的一种典型节律性活动。与呼吸一样，目前人们普遍认为，节律性口腔 - 面部运动基本模式的运动指令是由脑干中的神经元群体（中枢模式发生器，CPG）产生的。节律性咀嚼运动的中枢模式生成可分为三个过程：（1）咀嚼节律的产生，（2）颌骨、舌头和面部肌肉活动模式的产生，以及（3）这些肌肉活动的协调。有几条证据表明，咀嚼CPG在功能上可细分为两个神经元组：一个用于产生咀嚼节律，为颌骨闭合和张开的节律性交替提供定时信号（中枢节律发生器，CRG），另一个用于产生颌骨、舌头和面部肌肉活动的时空模式。本综述首先将探讨节律性咀嚼颌骨运动的CRG的定位、其激活源以及介导其输出至三叉神经运动神经元的运动前神经元。接下来，我们将讨论节律性三叉神经运动神经元活动以及中枢咀嚼节律产生的神经化学基础。最后，介绍了我们最近在体外制备中诱导反映吸吮运动（虚拟吸吮）的神经活动的尝试。
