中国物理B ›› 2026, Vol. 35 ›› Issue (6): 60508-060508.doi: 10.1088/1674-1056/ae0897
Yaqin Fan(樊亚琴)1, Meili Lu(卢梅丽)2, and Xile Wei(魏熙乐)3,†
Yaqin Fan(樊亚琴)1, Meili Lu(卢梅丽)2, and Xile Wei(魏熙乐)3,†
摘要: Evidence shows that there exist dendritic Ca$^{2+}$-spike-dependent and NMDA-spike-dependent multi-timescale compound oscillations in epileptiform activity, and the electric field (EF) plays a significant role in the propagation of compound oscillations. However, it is still unclear how the EF-induced spatial polarization modulates the interaction between dendritic Ca$^{2+}$ oscillations and NMDA oscillations, and subsequently influences somatic Na$^{+}$ spikes. To address this issue, we built a biophysical pyramidal neuron model with complex dendritic morphology, which is capable of reproducing multi-timescale neuronal oscillations observed in epileptiform discharges. By investigating the EF stimulation thresholds for triggering dendritic Ca$^{2+}$ and NMDA spikes as well as somatic Na$^{+}$ discharges, we found that the dendritic depolarization first activates dendritic Ca$^{2+}$ oscillations, subsequently leading to the generation of dendritic NMDA oscillations, which together facilitate Na$^{+}$ spike generation by counteracting somatic hyperpolarization. Finally, we proposed a minimal three-compartment neuronal model that successfully reproduces the Ca-NMDA-Na compound oscillations. Through singular perturbation and bifurcation analysis, we demonstrated the modulatory influence of EF on multi-timescale neuronal compound oscillations. Additionally, our results indicate that the EF-induced depolarization at the apical dendrite causes the system equilibrium point to experience an invariant circle saddle-node bifurcation to trigger dendritic Ca$^{2+}$ oscillations. These oscillations then drive the basal dendrite to generate dendritic NMDA oscillations by experiencing a subcritical Hopf bifurcation. In this case, the soma experiences a subcritical Hopf bifurcation to produce Na$^{+}$ spikes. These results provide valuable insights into the mechanisms underlying the generation of epileptiform discharges in the brain, which is helpful for developing therapeutic strategies for epilepsy.
中图分类号: (Nonlinear dynamics and chaos)