A Web-based simulation system of the spinal cord circuitry responsible for muscle control is described. The simulator employs two-compartment motoneuron models for S, FR and FF types, with synaptic inputs acting through conductance variations. Four motoneuron pools with their associated interneurons are represented in the simulator, with the possibility of inclusion of more than 2,000 neurons and 2,000,000 synapses. Each motoneuron action potential is followed, after a conduction delay, by a motor unit potential and a motor unit twitch. The sums of all motor unit potentials and twitches result in the electromyogram (EMG), and the muscle force, respectively. Inputs to the motoneuron pool come from populations of interneurons (Ia reciprocal inhibitory interneurons, Ib interneurons, and Renshaw cells) and from stochastic point processes associated with descending tracts. To simulate human electrophysiological experiments, the simulator incorporates external nerve stimulation with orthodromic and antidromic propagation. This provides the mechanisms for reflex generation and activation of spinal neuronal circuits that modulate the activity of another motoneuron pool (e.g., by reciprocal inhibition). The generation of the H-reflex by the Ia-motoneuron pool system and its modulation by spinal cord interneurons is included in the simulation system. Studies with the simulator may include the statistics of individual motoneuron or interneuron spike trains or the collective effect of a motor nucleus on the dynamics of muscle force control. Properties associated with motor-unit recruitment, motor-unit synchronization, recurrent inhibition and reciprocal inhibition may be investigated.

中文翻译：

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基于 Web 的架构中脊髓运动核和相关神经和肌肉的模拟系统。

描述了负责肌肉控制的脊髓电路的基于 Web 的模拟系统。该模拟器采用 S、FR 和 FF 类型的两室运动神经元模型，突触输入通过电导变化起作用。模拟器中显示了四个运动神经元池及其相关的中间神经元，可能包含超过 2,000 个神经元和 2,000,000 个突触。在传导延迟之后，每个运动神经元动作电位之后是运动单位电位和运动单位抽搐。所有运动单位电位和抽搐的总和分别产生肌电图 (EMG) 和肌肉力。运动神经元池的输入来自中间神经元群（Ia 相互抑制中间神经元、Ib 中间神经元、和 Renshaw 细胞）和来自与降束相关的随机点过程。为了模拟人体电生理实验，模拟器将外部神经刺激与顺向和逆向传播相结合。这为调节另一个运动神经元池的活动（例如，通过相互抑制）的脊髓神经元回路的反射生成和激活提供了机制。模拟系统中包括 Ia 运动神经元池系统产生的 H 反射及其脊髓中间神经元的调制。使用模拟器进行的研究可能包括单个运动神经元或中间神经元尖峰序列的统计数据或运动核对肌肉力量控制动力学的集体影响。与运动单位募集、运动单位同步、