Analysis of brainstem neural networks related to laryngeal multifunctional activities

呼吸，以及发声和上呼吸道的防御反射，如吞咽和咳嗽，是喉部的重要功能之一。为了确定喉部运动神经元呼吸相关活动的突触源，在失脑麻痹的猫中，使用位于Botzinger复核和吻侧腹侧呼吸组之间的呼吸神经元的尖峰作为触发点，对喉部运动神经元的膜电位进行了尖峰触发平均。我们确定了喉吸气运动神经元的一个兴奋性来源和两个抑制性来源，喉呼气运动神经元的两个抑制性来源。在喉吸气运动神经元中，激发模式增强的吸气神经元峰可诱发单突触兴奋性突触后电位，激发模式减弱的呼气神经元峰和激发模式减弱的吸气神经元峰可诱发单突触抑制性突触后电位（IPSPs）。在喉部运动神经元中，单突触IPSPs可由放电模式递减的吸气神经元峰和放电模式递增的呼气神经元峰诱发。我们认为，呼吸神经元的各种突触输入有助于形成喉运动神经元膜电位的呼吸相关轨迹。

Respiration, as well as vocalization and upper airway defensive reflexes such as swallowing and coughing, is one of the important laryngeal functions. To determine the synaptic source of the respiratory-related activity of laryngeal motoneurons, spike-triggered averaging of the membrane potentials of laryngeal motoneurons was conducted using spikes of respiratory neurons located between the Botzinger complex and the rostral ventral respiratory group as triggers in decerebrate, paralyzed cats. We identified one excitatory and two inhibitory sources for inspiratory laryngeal motoneurons, and two inhibitory sources for expiratory laryngeal motoneurons. In inspiratory laryngeal motoneurons, monosynaptic excitatory postsynaptic potentials were evoked by spikes of inspiratory neurons with augmenting firing patterns, and monosynaptic inhibitory postsynaptic potentials (IPSPs) were evoked by spikes of expiratory neurons with decrementing firing patterns and by spikes of inspiratory neurons with decrementing firing patterns. In expiratory laryngeal motoneurons, monosynaptic IPSPs were evoked by spikes of inspiratory neurons with decrementing firing patterns and by spikes of expiratory neurons with augmenting firing patterns. We conclude that various synaptic inputs from respiratory neurons contribute to shaping the respiratory-related trajectory of membrane potential of laryngeal motoneurons.