Mechanisms controlling the expression of a rhythmic behavior

描述（由申请人提供）：有节奏的行为产生对运动和呼吸等活动至关重要。这些系统的中断可能会导致执行简单任务的困难。由于这个原因，广泛的研究集中在节奏行为背后的机制上。在一些物种中，行为起始和振荡产生等领域已被很好地理解。然而，关于节律性行为持续时间的控制信息缺乏。神经系统如何能够维持产生持续行为所必需的高水平兴奋？本研究通过测试新的游泳-维持模型来研究药用水蛭对节奏游泳的维持。该模型基于初步和已发表的数据，提出多层次的控制协同工作以维持游泳。在尾侧中体神经节中发现了一种新的细胞“OM”，这种细胞的持续兴奋可以无限期地延长游泳时间。在尾侧脑中，已经确定了几个细胞，其抑制似乎是长时间游泳所必需的，其兴奋有助于游泳终止。锐电极电生理学将用于对这些新型游泳控制神经元的功能、细胞和电路特性进行分类。我们对水蛭游动网络中细胞间连接的详细了解使其成为计算机建模的绝佳系统。实验获得的数据将被输入Neurodynamix II程序，以测试游泳-维持模型是否确实可以解释游泳维持。这项研究的完成将增加我们对神经系统如何维持有节奏行为的理解，为研究更复杂物种的行为维持奠定基础。此外，这一建议将填补水蛭游泳系统在其他方面的重要空白，水蛭游泳系统可以用于研究其他领域，如脉冲编码、学习和记忆、行为选择和设计神经修复装置。

DESCRIPTION (provided by applicant): Rhythmic behavior production is essential for activities such as locomotion and breathing. A disruption to these systems can cause difficulties in executing even simple tasks. For this reason, extensive research has focused on the mechanisms behind rhythmic behaviors. Areas such as behavior-initiation and oscillation production are well understood in several species. However, there is a paucity of information regarding control of rhythmic behavior duration. How are nervous systems able to maintain the high level of excitation necessary to generate a sustained behavior? This proposal examines the maintenance of rhythmic swimming in the medicinal leech by testing the novel Swim-Maintenance Model. This model, based on preliminary and published data, proposes that multiple levels of control work in concert to sustain swimming. A novel cell, "OM", has been identified in a caudal midbody ganglion whose sustained excitation prolongs swimming indefinitely. In the caudal brain, several cells have been identified whose inhibition appears to be necessary for prolonged swimming, and whose excitation contributes to swim-termination. Sharp-electrode electrophysiology will be employed to classify the functional, cellular and circuit properties of these novel swim-control neurons. Our detailed knowledge of the cell-to-cell connections in leech swim-networks makes it an excellent system for computer modeling. Experimentally obtained data will be entered into the Neurodynamix II program to test if the Swim- Maintenance Model can, indeed, account for swim-maintenance. Completion of the proposed research will increase our understanding of how nervous systems sustain rhythmic behavior, forming a foundation for research on behavior maintenance in more complex species. Additionally, this proposal will fill an important gap in an otherwise well-characterized leech swim-system that can be used to study other areas such as spike coding, learning and memory, behavioral choice and in designing neuro-prosthetic devices. PUBLIC HEALTH RELEVANCE: Completion of this proposal will elucidate mechanisms that sustain rhythmic behavior, an area that is poorly understood. This information can be applied in designing therapies to treat injured rhythmic systems such as the spinal cord.