Loppini Alessandro, Pedersen Morten Gram
Unit of Nonlinear Physics and Mathematical Modeling, Campus Bio-Medico University of Rome, I-00128 Rome, Italy.
Department of Information Engineering, University of Padua, I-35131 Padua, Italy.
Chaos. 2018 Jun;28(6):063111. doi: 10.1063/1.5022217.
Pancreatic β-cells show multiple intrinsic modes of oscillation with bursting electrical activity playing a crucial role. Bursting is seen both in experimentally isolated β-cells as well as in electrically coupled cells in the pancreatic islets, but the burst period is typically an order of magnitude greater in coupled cells. This difference has previously been attributed to noisier dynamics, or perturbed electrophysiological properties, in isolated β-cells. Here, we show that diffusive coupling alone can extend the period more than ten-fold in bursting oscillators modeled with a so-called phantom burster model and analyze this result with slow-fast bifurcation analysis of an electrically coupled pair of cells. Our results should be applicable to other scenarios where coupling of bursting units, e.g., neurons, may increase the oscillation period drastically.
胰腺β细胞表现出多种内在振荡模式，其中爆发性电活动起着关键作用。在实验分离的β细胞以及胰岛中电耦合的细胞中都能观察到爆发活动，但耦合细胞中的爆发周期通常要大一个数量级。此前，这种差异被归因于分离的β细胞中更嘈杂的动力学或受干扰的电生理特性。在此，我们表明，仅扩散耦合就能使采用所谓虚拟爆发器模型建模的爆发振荡器的周期延长十倍以上，并通过对一对电耦合细胞进行快慢分岔分析来分析这一结果。我们的结果应适用于其他爆发单元（如神经元）耦合可能大幅增加振荡周期的情况。
