Generation of variants of a motor act in a modular and hierarchical motor network
Generation of variants of a motor act in a modular and hierarchical motor network
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DOI：
10.1016/j.cub.2005.08.051
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发表时间：
2005-10-11
期刊：
影响因子：
9.2
通讯作者：
Weiss, KR
中科院分区：
文献类型：
--
作者：
Jing, J;Weiss, KR
背景：大多数运动系统可以产生各种行为，包括完全不同的行为和同一行为类别中单一运动行为的变体。以往的工作表明，许多产生模式的神经元间网络可能具有模块化的组织结构，并且可以通过少量模块或构建块的灵活组合来产生不同类别的行为。然而，目前还不清楚少量的模块是否以及如何可能产生一种行为的大量变体。结果：我们发现海兔的模块化摄食运动网络调节了咬人类程序中延长时间的变化。两个下行指令在咬合行为中是激活的，并在半完整的准备过程中触发类似咬的反应。在孤立的CNS中，当单独激活时，这两个命令通过专门作用于对延长持续时间有相反影响的两个模块，产生长或短的咬合式程序。更重要的是，当两种指令以不同的频率共同激活时，它们会产生中间延长时间的咬人程序。结论：先前的假设是，多个下行指令的不同活动水平可能会产生行为变异。我们的数据为这种方案提供了直接证据，并显示了它是如何在模块化组织的网络中实现的。因此，在模块化和分层体系结构中，除了生成不同类别的行为外，少量模块还有效地实现单个行为的变体。
Background: Most motor systems can generate a variety of behaviors, including categorically different behaviors and variants of a single motor act within the same behavioral category. Previous work indicated that many pattern-generating interneuronal networks may have a modular organization and that distinct categories of behaviors can be generated through flexible combinations of a small number of modules or building blocks. However, it is unclear whether and how a small number of modules could possibly generate a large number of variants of one behavior.Results: We show that the modular feeding motor network of Aplysia mediates variations in protraction duration in biting-like programs. Two descending commands are active during biting behavior and trigger biting-like responses in a semiintact preparation. In the isolated CNS, when activated alone, the two commands produce biting-like programs of either long or short protraction duration by acting specifically on two modules that have opposite effects on protraction duration. More importantly, when coactivated at different frequencies, the two commands produce biting programs with an intermediate protraction duration.Conclusions: It was previously hypothesized that behavioral variants may be produced by combining different activity levels of multiple descending commands. Our data provide direct evidence for such a scheme and show how it is implemented in a modularly organized network. Thus, within a modular and hierarchical architecture, in addition to generating different categories of behavior, a small number of modules also efficiently implements variants of a single behavior.