Department of Brain and Cognitive Sciences, McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Biomedical Engineering, Duke University, Durham, NC, 27708, USA.
Science. 2024 Mar 8;383(6687):eadi8081. doi: 10.1126/science.adi8081.
Phonation critically depends on precise controls of laryngeal muscles in coordination with ongoing respiration. However, the neural mechanisms governing these processes remain unclear. We identified excitatory vocalization-specific laryngeal premotor neurons located in the retroambiguus nucleus (RAm) in adult mice as being both necessary and sufficient for driving vocal cord closure and eliciting mouse ultrasonic vocalizations (USVs). The duration of RAm activation can determine the lengths of both USV syllables and concurrent expiration periods, with the impact of RAm activation depending on respiration phases. RAm neurons receive inhibition from the preBötzinger complex, and inspiration needs override RAm-mediated vocal cord closure. Ablating inhibitory synapses in RAm neurons compromised this inspiration gating of laryngeal adduction, resulting in discoordination of vocalization with respiration. Our study reveals the circuits for vocal production and vocal-respiratory coordination.
发声在很大程度上取决于喉部肌肉的精确控制，这些肌肉与持续的呼吸协调一致。然而，支配这些过程的神经机制仍不清楚。我们在成年小鼠的后疑核（RAm）中鉴定出兴奋性发声特异性喉前运动神经元，它们既是驱动声带闭合和引发小鼠超声发声（USVs）所必需的，也是充分的。RAm 的激活持续时间可以决定 USV 音节和同期呼气期的长度，而 RAm 激活的影响取决于呼吸阶段。RAm 神经元受到前包钦格复合体的抑制，吸气需要优先于 RAm 介导的声带闭合。在 RAm 神经元中消融抑制性突触会损害这种声带内收的吸气门控，导致发声与呼吸不协调。我们的研究揭示了发声和发声-呼吸协调的回路。
