Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States; Department of Neurobiology, Duke University, Durham, United States
Jae Hong Park
Department of Biomedical Engineering, Duke University, Durham, United States
Jinghao Lu
Department of Neurobiology, Duke University, Durham, United States
Section of Neurobiology, University of California at San Diego, San Diego, United States; Department of Physics, University of California at San Diego, San Diego, United States
Beth Friedman
Department of Computer Science and Engineering, University of California at San Diego, San Diego, United States
Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States; Department of Neurobiology, Duke University, Durham, United States; Department of Biomedical Engineering, Duke University, Durham, United States
Premotor circuits in the brainstem project to pools of orofacial motoneurons to execute essential motor action such as licking, chewing, breathing, and in rodent, whisking. Previous transsynaptic tracing studies only mapped orofacial premotor circuits in neonatal mice, but the adult circuits remain unknown as a consequence of technical difficulties. Here, we developed a three-step monosynaptic transsynaptic tracing strategy to identify premotor neurons controlling vibrissa, tongue protrusion, and jaw-closing muscles in the adult mouse. We registered these different groups of premotor neurons onto the Allen mouse brain common coordinate framework (CCF) and consequently generated a combined 3D orofacial premotor atlas, revealing unique spatial organizations of distinct premotor circuits. We further uncovered premotor neurons that simultaneously innervate multiple motor nuclei and, consequently, are likely to coordinate different muscles involved in the same orofacial motor actions. Our method for tracing adult premotor circuits and registering to Allen CCF is generally applicable and should facilitate the investigations of motor controls of diverse behaviors.
