Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, Newark, NJ, USA.
Corresponding Investigator, CONICET, Buenos Aires, Argentina.
J Comput Neurosci. 2022 Aug;50(3):331-355. doi: 10.1007/s10827-022-00819-7. Epub 2022 Jun 2.
Neuronal systems are subject to rapid fluctuations both intrinsically and externally. These fluctuations can be disruptive or constructive. We investigate the dynamic mechanisms underlying the interactions between rapidly fluctuating signals and the intrinsic properties of the target cells to produce variable and/or coherent responses. We use linearized and non-linear conductance-based models and piecewise constant (PWC) inputs with short duration pieces. The amplitude distributions of the constant pieces consist of arbitrary permutations of a baseline PWC function. In each trial within a given protocol we use one of these permutations and each protocol consists of a subset of all possible permutations, which is the only source of uncertainty in the protocol. We show that sustained oscillatory behavior can be generated in response to various forms of PWC inputs independently of whether the stable equilibria of the corresponding unperturbed systems are foci or nodes. The oscillatory voltage responses are amplified by the model nonlinearities and attenuated for conductance-based PWC inputs as compared to current-based PWC inputs, consistent with previous theoretical and experimental work. In addition, the voltage responses to PWC inputs exhibited variability across trials, which is reminiscent of the variability generated by stochastic noise (e.g., Gaussian white noise). Our analysis demonstrates that both oscillations and variability are the result of the interaction between the PWC input and the target cell's autonomous transient dynamics with little to no contribution from the dynamics in vicinities of the steady-state, and do not require input stochasticity.
神经元系统受到内在和外在的快速波动的影响。这些波动可能具有破坏性，也可能具有建设性。我们研究了快速波动的信号与目标细胞内在特性之间相互作用的动态机制，以产生可变和/或相干的反应。我们使用线性化和基于电导的非线性模型以及具有短持续时间片段的分段常数 (PWC) 输入。常数片段的幅度分布由基线 PWC 函数的任意排列组成。在给定协议内的每次试验中，我们使用这些排列中的一种，并且每个协议由所有可能排列的子集组成，这是协议中唯一的不确定性来源。我们表明，响应各种形式的 PWC 输入可以产生持续的振荡行为，而与相应未受扰系统的稳定平衡点是焦点还是节点无关。与基于电流的 PWC 输入相比，模型的非线性会放大振荡电压响应，并衰减基于电导的 PWC 输入，这与之前的理论和实验工作一致。此外，PWC 输入的电压响应在试验之间表现出可变性，这让人联想到由随机噪声（例如高斯白噪声）产生的可变性。我们的分析表明，无论是振荡还是可变性，都是 PWC 输入与目标细胞自主瞬态动力学相互作用的结果，几乎没有来自稳态附近动力学的贡献，也不需要输入随机性。
