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Environmental Impacts on Spiking Properties in Hodgkin-Huxley Neuron with Direct Current Stimulus 下载免费PDF全文
Based on the well accepted Hodgkin-Huxley neuron model, the neuronal intrinsic excitability is studied when the neuron is subject to varying environmental temperatures, the typical impact for its regulating ways. With computer simulation, it is found that altering environmental temperature can improve or inhibit the neuronal intrinsic excitability so as to influence the neuronal spiking properties. The impacts from environmental factors can be understood that,the neuronal spiking threshold is essentially influenced by the fluctuations in the environment. With the environmental temperature varying, burst spiking is realized for the neuronal membrane voltage because of the environment-dependent spiking threshold. This burst induced by changes in spiking threshold is different from that excited by input currents or other stimulus. 相似文献
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提出了布朗马达的非均匀高斯跃迁理论,用布朗粒子在多态之间的跃迁模型描述分子马达的定向运动.假定跃迁速率与位置有关,且在跃迁点附近具有高斯函数形式,将布朗粒子在x处的概率密度Pm(x,t)在跃迁点附近展开,可以进行任意阶的近似计算.这一理论涵盖了以往的定点跃迁模型和均匀跃迁模型.作为具体例子,研究了系统在两态之间的跃迁问题.假定在一个周期内有两个跃迁点,讨论了布朗粒子定向运动产生的概率流随温度、跃迁速率和
跃迁宽度的变化关系.
关键词:
布朗马达
高斯跃迁
概率流 相似文献
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F1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the central γ-subunit rotates inside the α3β3 cylinder. A stochastic four-state mechanochemical coupling model of F1-ATPase is studied with the aid of the master equation. In this model, the ATP hydrolysis and synthesis are dependent on ATP, ADP, and Pi concentrations. The effects of ATP concentration, ADP concentration, and the external torque on the occupation probability of binding-state, the rotation rate and the diffusion coefficient of F1-ATPase are investigated. Moreover, the results from this model are compared with experiments. The mechanochemical mechanism F1-ATPase is qualitatively explained by the model. 相似文献
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分子马达是一类将化学能转化为机械能的微小机器. 对二维模型的研究表明, 非保守力在体系与外界能量交换中发挥重要作用. 四态模型较好地反映了马达力学化学过程的各个状态及相应的构象变化. Motor protein is a kind of small machines that convert chemical energy to mechanical works. It is revealed from the study of the two dimensional model that the non conservative impulsive force plays a significant role in the exchanging process of energy. A four state model characterizing the coupling of mechanical and chemical processes of molecular motor is also discussed. 相似文献
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为了使Eigen模型能够更真实地描述物种的演化过程,将确定性Eigen模型改造成随机模型.以Eigen模型为理论框架,把基因序列中每一个位点的突变率看作一个高斯随机变量,从而导出随机性Eigen模型.对于此随机性Eigen模型,当突变率的涨落强度较小时,准物种的误差阈位置几乎没有改变,仍是个相变点;而当突变率的涨落强度变大时,误差阈由一个相变点变为一个转变区域.在真实的物种演化过程中,误差阈应是一个转变区域,而且在解决实际问题时应考虑该转变区域的上限. 相似文献
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A flashing coloured noise model is proposed to describe the motion of a molecular motor.In this model,the overdamped Brownian particle moves in an asymmetric periodic potential with a flashing Ornstein-Ulenbeck coloured noise.The relationship between the current and the parameters-such as the intensity,the correlation time of coloured noise and the flip rate of the noise-is discussed using the Monte Carlo simulation method.Current reversal occurs with the change of the correlation time and the flip rate of coloured noise,which may be related to the directed motion and the current reversal of molecular motors. 相似文献