Analysis of neural network generating laryngeal multifunctional activities

喉提供各种行为，包括发声，呼吸和呼吸道保护反射，如吞咽和咳嗽。为了阐明喉运动模式产生的神经机制，在去大脑和麻痹的猫在虚拟呼吸和吞咽过程中记录了呼气（ELMs）和吸气（ILMs）喉运动神经元的膜电位轨迹。ELMs在呼吸的吸气阶段和吞咽的咽部阶段的开始时被超极化，而ILMs在呼吸的吸气后阶段和吞咽的整个咽部阶段期间被超极化。这种超极化的膜电位在ELMs的咽部阶段的初始部分和整个咽部阶段在ILMs中观察到的逆转由细胞内注射氯离子和去极化由细胞外注射GABA拮抗剂。这些结果表明，氯依赖性，GABA能抑制输入ELMs和ILMs参与喉运动序列的时间组织在行为过程中。

The larynx serves various behaviors including vocalization, breathing and airway protection reflexes such as swallowing and conghing. To elucidate the neural mechanism generating laryngeal motor patterns during the behaviors, the membrane potential trajectories of expiratory (ELMs) and inspiratory (ILMs) laryngeal motoneurons were recorded during fictive breathing and swallowing in decerebrated and paralyzed cats. ELMs were hyperpolarized during the inspiratory phase of breathing and at the onset of the pharyngeal stage of swallowing, whereas ILMs were hyperpolarized during the post-inspiratory phase of breathing and during the whole pharyngeal stage of swallowing. Such hyperpolarized membrane potentials observed during the initial part of pharyngeal stage in ELMs and during the whole pharyngeal stage in ILMs were reversed by intracellular injection of chloride ions and depolarized by extracellular injection of GABA antagonist. These results suggest that chloride-dependent, GABAergic inhibitory inputs to ELMs and ILMs are involved in the temporal organization of the laryngeal motor sequence during the behaviors.