Detailed model of intersegmental coordination in the timing network of the leech heartbeat central pattern generator
Detailed model of intersegmental coordination in the timing network of the leech heartbeat central pattern generator
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DOI：
10.1152/jn.00656.2003
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发表时间：
2004-02-01
影响因子：
2.5
通讯作者：
Calabrese, RL
中科院分区：
文献类型：
--
作者：
Jezzini, SH;Hill, AAV;Calabrese, RL
为了解决振荡神经元网络节段间协调的一般问题，我们研究了水蚤心跳中枢模式发生器。该模式发生器的核心是一个由两个分段振荡器组成的定时网络，每个分段振荡器由两个识别的、相互抑制的振荡器中间神经元组成。节段性振荡器之间的节间协调是通过振荡器中间神经元和已识别的协调中间神经元之间的突触相互作用来调节的。少量神经元(8)和时序网络的分布式结构使分段振荡器作为离散的、独立的单元的实验分析成为可能。在这项实验工作的基础上，我们制作了基于电导的模型，以探索节间相和周期是如何确定的。我们表明，尽管以前的一个简单的模型忽略了生命系统的许多细节，复制了生命系统的一些基本特征，但为了捕捉在不同实验条件下看到的系统行为，结合特定的细胞和网络属性是必要的。例如，协调中间神经元的尖峰频率适应和节段间连接中不对称的细节对于重复驱动实验是必要的，在该实验中，一个节段振荡器被注入周期性的电流脉冲，以吸引整个网络的活动。然而，这里展示的相位和周期控制的基本机制似乎是非常普遍的，可以被其他产生协调节段性运动流出的网络所使用。
To address the general problem of intersegmental coordination of oscillatory neuronal networks, we have studied the leech heartbeat central pattern generator. The core of this pattern generator is a timing network that consists of two segmental oscillators, each of which comprises two identified, reciprocally inhibitory oscillator interneurons. Intersegmental coordination between the segmental oscillators is mediated by synaptic interactions between the oscillator interneurons and identified coordinating interneurons. The small number of neurons ( 8) and the distributed structure of the timing network have made the experimental analysis of the segmental oscillators as discrete, independent units possible. On the basis of this experimental work, we have made conductance-based models to explore how intersegmental phase and cycle period are determined. We show that although a previous simple model, which ignored many details of the living system, replicated some essential features of the living system, the incorporation of specific cellular and network properties is necessary to capture the behavior of the system seen under different experimental conditions. For example, spike frequency adaptation in the coordinating interneurons and details of asymmetries in intersegmental connectivity are necessary for replicating driving experiments in which one segmental oscillator was injected with periodic current pulses to entrain the activity of the entire network. Nevertheless, the basic mechanisms of phase and period control demonstrated here appear to be very general and could be used by other networks that produce coordinated segmental motor outflow.