Fast or slow? Cellular and molecular adaptations underlying different frequency regimes in spinal motor systems

移动的能力对于动物生命中最重要的任务至关重要：寻找庇护所或食物以及繁殖成功。在脊椎动物中，运动是由脊髓回路控制的，脊髓回路产生两侧组织的骨骼肌的交替收缩。独立于运动方式，如行走、跑步、游泳、飞行或爬行，高度保守的脊髓运动回路，即，中枢模式发生器（CPG）协调支配骨骼肌的运动神经元的活动。虽然起伏和双足或四足运动动物之间的一般脊髓蓝图回路的适应导致不同的运动模式，但个体运动模式（例如双侧交替骨骼收缩）在快速或缓慢运动动物之间显示出广泛不同的频率范围。拟议的研究的目标是调查，在网络，细胞和分子水平上，使进化保守的神经元电路产生广泛不同的频率制度的机制。响尾蛇提供了一个独特的机会来解决这个问题，因为它们在不同的频率范围内产生两种不同的脊椎行为。脊髓的主要部分产生低频交替肌肉收缩序列的运动（约。4- 15 Hz），而脊髓的最尾部产生高频交替模式（约10 Hz）。80-120 Hz）用于声音信号（嘎嘎声）。在一个动物的两个功能不同的脊柱系统的存在提供了一个独特的机会，调查进化适应，使或导致高度发散的频率制度，而不必考虑可能的种间差异。使用电生理学，药理学，解剖学和分子的方法，这项研究的目标是阐明负责这些广泛不同的频率制度在网络，单细胞和分子水平的机制。一般的假设是，一般的脊髓网络组织保留在两种不同的响尾蛇脊髓模式之间，细胞适应导致不同的频率制度。这项研究将有助于阐明如何共享一个共同的进化起源的神经元电路可以修改，以表达不同的behaviors.Summary：利用存在的慢（运动）和快（摇铃系统）的响尾蛇的脊髓运动系统，拟议的研究的目标是了解潜在的机制，导致不同的频率制度，共享一个共同的进化起源的神经元电路。

The ability to move is essential for the most important tasks in an animals life: the search for shelter or food and reproductive success. In vertebrates, locomotion is governed by spinal circuits that generate alternating contractions of bilaterally organized skeletal muscles. Independent of locomotor style, such as walking, running, swimming, flying or crawling, highly conserved spinal locomotor circuits, i.e., central pattern generators (CPGs), coordinate the activity of motoneurons innervating the skeletal muscles. While adaptations in the general spinal blueprint circuit between undulating and bi- or quadrupedal moving animals lead to different locomotor patterns, individual motor patterns (e.g. bilaterally alternating skeletal contractions) display widely diverging ranges of frequencies between fast or slowly moving animals. The goal of the proposed study is to investigate, at a network, cellular and molecular level, the mechanisms that enable evolutionarily conserved neuronal circuits to generate widely different frequency regimes. Rattlesnakes offer a unique opportunity to address this question since they produce two different spinal behaviors at distinct frequency ranges. The predominant part of the cord generates low frequency alternating muscle contraction sequences for locomotion (ca. 4-15Hz), whereas the most caudal part of the spinal cord generates high frequency alternating patterns (ca. 80-120 Hz) for acoustic signaling (rattling). The presence of two functionally different spinal systems in one animal provides a unique opportunity to investigate evolutionary adaptations that enable or cause highly diverging frequency regimes without having to consider possible interspecies differences. Using electrophysiological, pharmacological, anatomical and molecular methods, the goal of this proposed study is to elucidate the mechanisms responsible for these widely different frequency regimes at a network, single cell, and molecular level. The general hypothesis is that the general spinal network organization is retained between the two different rattlesnake spinal patterns, and that cellular adaptations lead to the different frequency regimes. This study will help shed light on how neuronal circuits that share a common evolutionary origin can be modified to express different behaviors.Summary: Taking advantage of the presence of slow (locomotion) and fast (rattling system) spinal motor systems in the rattlesnake, the goal of the proposed study is to understand the underlying mechanisms leading to different frequency regimes in neuronal circuits that share a common evolutionary origin.