Effects of potassium channel blockage on inverse stochastic resonance in Hodgkin-Huxley neural systems

Abstract

Inverse stochastic resonance (ISR) is a phenomenon in which the firing activity of a neuron is inhibited at a certain noise level. In this paper, the effects of potassium channel blockage on ISR in single Hodgkin-Huxley neurons and in small-world networks were investigated. For the single neuron, the ion channel noise-induced ISR phenomenon can occur only in a certain small range of potassium channel blockage ratio. Bifurcation analysis showed that this small range is the bistable region regulated by the external bias current. For small-world networks, the effect of non-homogeneous network blockage on ISR was investigated. The network blockage ratio was used to represent the proportion of potassium-channel-blocked neurons to total network neurons. It is found that an increase in network blockage ratio at small coupling strengths results in shorter ISR duration. When the coupling strength is increased, the ISR is more significant in the case of a large network blockage ratio. The ISR phenomenon is determined by the network blockage ratio, the coupling strength, and the ion channel noise. Our results will provide new perspectives on the observation of ISR in neuroscience experiments.

概要

目的

研究钾离子通道阻塞对单个Hodgkin-Huxley神经元和小世界网络中反随机共振(ISR)的影响,并分析背后的动力学机制。

创新点

1. 探究钾离子通道阻塞对反随机共振的影响;2. 在小世界网络中考虑阻塞不均匀对反随机共振的影响。

方法

1. 以放电率作为统计量,研究钾离子通道阻塞对神经元放电率的影响(图2和3);2. 通过分岔分析,探究钾 离子通道阻塞对反随机共振所产生影响背后的动力学机制(图4);3. 探究部分阻塞的神经元网络中反随 机共振对耦合强度的依赖性(图8和13);4. 通过相空间和网络中神经元的放电分布等分析不同反随机共 振曲线背后的动力学机制(图10~12)。

结论

1. 对于单个神经元,离子通道噪声引起的ISR现象只发生在较小的钾离子通道阻塞率范围内;分岔分析表明这 一小范围是受外部偏置电流影响的双稳态区域。2. 对于小世界神经元网络,ISR存在的原因是在中等强度 噪声下双稳态神经元的放电受到抑制。3. 当双稳态和单稳态神经元之间存在电位差,且耦合强度增加时, 抑制作用被抵消。4. 在较小的耦合强度下,网络阻塞比的增加会导致ISR持续时间变短;当耦合强度增加 时,ISR在网络阻塞比较大的情况下更为明显;ISR现象由网络阻塞比、耦合强度和离子通道噪声共同决 定。