Dynamical Mechanism of Hyperpolarization-Activated Non-specific Cation Current Induced Resonance and Spike-Timing Precision in a Neuronal Model

作者：Zhao Zhiguo; Li Li; Gu Huaguang

来源：Frontiers in Cellular Neuroscience, 2018, 12: 62.

DOI：10.3389/fnce1.2018.00062

• hyperpolarization-activated current
• post-inhibitory rebound
• subthreshold resonance
• spike-timing precision
• bifurcations
• temporal coding

Hyperpolarization-activated cyclic nucleotide-gated cation current (l(h)) plays important roles in the achievement of many physiological/pathological functions in the nervous system by modulating the electrophysiological activities, such as the rebound (spike) to hyperpolarization stimulations, subthreshold membrane resonance to sinusoidal currents, and spike-timing precision to stochastic factors. In the present paper, with increasing gh (conductance of l(h)), the rebound (spike) and subthreshold resonance appear and become stronger, and the variability of the interspike intervals (vertical bar S vertical bar(s)) becomes lower, i.e., the enhancement of spike-timing precision, which are simulated in a conductance-based theoretical model and well explained by the nonlinear concept of bifurcation. With increasing gh, the stable node to stable focus, to coexistence behavior, and to firing via the codimension-1 bifurcations (Hopf bifurcation, saddle-node bifurcation, saddle-node bifurcations on an invariant circle, and saddle homoclinic orbit) and codimension-2 bifurcations such as Bogdanov-Takens (BT) point related to the transition between saddle-node and Hopf bifurcations, are acquired with 1 and 2-parameter bifurcation analysis. The decrease of variability of vertical bar S vertical bar s with increasing gh is induced by the fast decrease of the standard deviation of vertical bar S vertical bar s, which is related to the increase of the capacity of resisting noisy disturbance due to the firing becomes far away from the bifurcation point. The enhancement of the rebound (spike) with increasing gh builds up a relationship to the decrease of the capacity of resisting disturbance like the hyperpolarization stimulus as the resting state approaches the bifurcation point. The "typical"-resonance and non-resonance appear in the parameter region of the stable focus and node far away from the bifurcation points, respectively. The complex or "strange" dynamics, such as the "weak"-resonance for the stable node near the transition point between the stable node and focus and the non-resonance for the stable focus close to the codimension-1 and 2 bifurcation points, are discussed.

• 出版日期2018-3-8
• 单位河南工程学院; 同济大学