Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Dev Neurobiol. 2018 Dec;78(12):1218-1230. doi: 10.1002/dneu.22647. Epub 2018 Nov 11.
Many vital motor behaviors - including locomotion, swallowing, and breathing - appear to be dependent upon the activity of and coordination between multiple endogenously rhythmogenic nuclei, or neural oscillators. Much as the functional development of sensory circuits is shaped during maturation, we hypothesized that coordination of oscillators involved in motor control may likewise be maturation-dependent, i.e., coupling and coordination between oscillators change over development. We tested this hypothesis using the bullfrog isolated brainstem preparation to study the metamorphic transition of ventilatory motor patterns from early rhythmic buccal (water) ventilation in the tadpole to the mature pattern of rhythmic buccal and lung (air) ventilation in the adult. Spatially distinct oscillators drive buccal and lung bursts in the isolated brainstem; we found these oscillators to be active but functionally uncoupled in the tadpole. Over the course of metamorphosis, the rhythms produced by the buccal and lung oscillators become increasingly tightly coordinated. These changes parallel the progression of structural and behavioral changes in the animal, with adult levels of coupling arising by the metamorphic stage (forelimb eruption). These findings suggest that oscillator coupling undergoes a maturation process similar to the refinement of sensory circuits over development.
许多重要的运动行为——包括运动、吞咽和呼吸——似乎依赖于多个内源性节律生成核或神经振荡器的活动和协调。就像感觉回路的功能发育在成熟过程中受到塑造一样，我们假设参与运动控制的振荡器的协调也可能依赖于成熟，即振荡器之间的耦合和协调随着发育而变化。我们使用牛蛙离体脑干制备物来研究通气运动模式的变态过渡，从早期的节律性口部（水）通气转变为成年时的节律性口部和肺部（空气）通气。空间上不同的振荡器驱动离体脑干中的口部和肺部爆发；我们发现这些振荡器在蝌蚪中活跃但功能上不耦合。在变态过程中，口部和肺部振荡器产生的节律变得越来越紧密协调。这些变化与动物的结构和行为变化的进展平行，在变态阶段（前肢爆发）出现成年水平的耦合。这些发现表明，振荡器耦合经历了一个类似于发育过程中感觉回路细化的成熟过程。
