Schmerl Brett A, McDonnell Mark D
Computational and Theoretical Neuroscience Laboratory, Institute for Telecommunications Research, University of South Australia, South Australia 5095, Australia.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Nov;88(5):052722. doi: 10.1103/PhysRevE.88.052722. Epub 2013 Nov 26.
Neuronal membrane potentials fluctuate stochastically due to conductance changes caused by random transitions between the open and closed states of ion channels. Although it has previously been shown that channel noise can nontrivially affect neuronal dynamics, it is unknown whether ion-channel noise is strong enough to act as a noise source for hypothesized noise-enhanced information processing in real neuronal systems, i.e., "stochastic facilitation". Here we demonstrate that biophysical models of channel noise can give rise to two kinds of recently discovered stochastic facilitation effects in a Hodgkin-Huxley-like model of auditory brainstem neurons. The first, known as slope-based stochastic resonance (SBSR), enables phasic neurons to emit action potentials that can encode the slope of inputs that vary slowly relative to key time constants in the model. The second, known as inverse stochastic resonance (ISR), occurs in tonically firing neurons when small levels of noise inhibit tonic firing and replace it with burstlike dynamics. Consistent with previous work, we conclude that channel noise can provide significant variability in firing dynamics, even for large numbers of channels. Moreover, our results show that possible associated computational benefits may occur due to channel noise in neurons of the auditory brainstem. This holds whether the firing dynamics in the model are phasic (SBSR can occur due to channel noise) or tonic (ISR can occur due to channel noise).
由于离子通道开放和关闭状态之间的随机转换所引起的电导变化，神经元膜电位会随机波动。尽管此前已有研究表明通道噪声能够以非平凡的方式影响神经元动力学，但尚不清楚离子通道噪声是否强大到足以在真实的神经元系统中作为一种噪声源，用于假设的噪声增强信息处理，即“随机促进”。在此，我们证明通道噪声的生物物理模型能够在听觉脑干神经元的类霍奇金 - 赫胥黎模型中引发两种最近发现的随机促进效应。第一种，称为基于斜率的随机共振（SBSR），使相位神经元能够发放动作电位，这些动作电位可以编码相对于模型中的关键时间常数缓慢变化的输入信号的斜率。第二种，称为逆随机共振（ISR），发生在持续发放的神经元中，当低水平噪声抑制持续发放并将其替换为爆发式动态时。与之前的工作一致，我们得出结论，即使对于大量通道，通道噪声也能在发放动力学中提供显著的变异性。此外，我们的结果表明，由于听觉脑干神经元中的通道噪声，可能会出现相关的计算益处。无论模型中的发放动力学是相位性的（通道噪声可导致SBSR）还是持续性的（通道噪声可导致ISR），都是如此。
