Metachronal coupling between spinal neuronal networks during locomotor activity in newborn rat
Metachronal coupling between spinal neuronal networks during locomotor activity in newborn rat
复制标题
DOI：
10.1113/jphysiol.2006.115709
复制
发表时间：
2007-04-01
影响因子：
5.5
通讯作者：
Cazalets, Jean-Rene
中科院分区：
文献类型：
--
作者：
Falgairolle, Melanie;Cazalets, Jean-Rene
在本研究中，我们研究了新生大鼠在运动过程中脊髓神经网络的相互作用。从运动学、解剖学和体外电生理数据推断出异时传播运动活动的行为和生理相关性。对自由行为动物的运动学分析表明，在阶跃循环中躯干曲率有节律性的顺序变化。采用逆行标记法沿脊髓方向识别支配背、尾肌的运动神经元。系统的多次记录从腹根被用来确定精确的内在模式的协调在孤立的脊髓。在类似运动的活动中，有节奏的腹侧神经根运动爆发在骶脊髓和胸脊髓区域向尾侧传播。将潜伏期绘制为周期的函数，表明系统使节间潜伏期适应于正在进行的运动周期，以保持沿脊柱轴的恒定相位关系。当分离时，胸椎、腰椎和骶骨区域能够产生左右交替的运动爆发。脊髓纵切面显示，骶区相对于腰2节段的双侧反相模式以及节段间相滞后都是由于脊髓交叉连接造成的。总之，这些结果提供了生理学证据，表明运动过程中躯干弯曲的动态变化是由脊髓网络的内在组织及其纵向和横向相互作用决定的。这种组织与更原始的脊椎动物的运动模式产生的组织之间的相似性表明，在运动过程中负责运动模式的异向传播的电路是高度保守的。
In the present study, we investigate spinal cord neuronal network interactions in the neonatal rat during locomotion. The behavioural and physiological relevance of metachronally propagated locomotor activity were inferred from kinematic, anatomical and in vitro electrophysiological data. Kinematic analysis of freely behaving animals indicated that there is a rhythmic sequential change in trunk curvature during the step cycle. The motoneurons innervating back and tail muscles were identified along the spinal cord using retrograde labelling. Systematic multiple recordings from ventral roots were made to determine the precise intrinsic pattern of coordination in the isolated spinal cord. During locomotor-like activity, rhythmic ventral root motor bursts propagate caudo-rostrally in the sacral and the thoracic spinal cord regions. Plotting the latency as a function of the cycle period revealed that the system adapts the intersegmental latency to the ongoing motor period in order to maintain a constant phase relationship along the spinal axis. The thoracic, lumbar and sacral regions were capable of generating right and left alternating motor bursts when isolated. Longitudinal sections of the spinal cord revealed that both the bilateral antiphase pattern observed for the sacral region with respect to the lumbar segment 2 as well as the intersegmental phase lag were due to cross-cord connections. Together, these results provide physiological evidence that the dynamic changes observed in trunk bending during locomotion are determined by the intrinsic organization of spinal cord networks and their longitudinal and transverse interactions. Similarities between this organization, and that of locomotor pattern generation in more primitive vertebrates, suggest that the circuits responsible for metachronal propagation of motor patterns during locomotion are highly conserved.