细胞丛状化分布对二维耦合体系尺度选择效应的影响

采用随机模拟方法对体系的化学朗之万方程进行了数值模拟，考察了二维耦合细胞体系中，细胞的丛状化分布对于因内噪声作用而产生的尺度选择效应所带来的影响.研究发现，当体系处于Hopf分岔点附近时，由于耦合作用使得处于最佳状态的一定数目的细胞呈现丛状化聚集在一起，而这种丛状化分布的“团队精神”可以极大地提高体系的工作效率，表现为体系对外界刺激信号的响应能力(信噪比)达到极大值.同时还观察到，体系对外界刺激最为敏感时对应的最佳细胞丛尺度大小不随耦合强度的改变而变化，而体系输出信号的信噪比，随着耦合强度的增加有增大趋势.这些现象表明，细胞的丛状化分布将极大地增强细胞中钙离子信号对外界刺激的响应效果.生物体系本身可能具有这种特性，并利用它来改善和提高感受外界信息的能力.

System size selected effects induced by clustering in two-dimensional coupled cell systems

Using stochastic simulation and chemical Langevin methods, we numerically investigated the influence of clustering of cells on the system size effects in two-dimensional coupled internal noisy cell systems. It was found that, when the system works near the Hopf bifurcation, the systems' cells assemble to a team in forming, a cell cluster. Interestingly, the teamwork in clustering may significantly raise the system's working efficiency, leading to the system obtaining the best performance under external stimulus. Furthermore, for different coupling intensities the optimal cluster size varies in robustness to external stimuli, but the signal-to-noise ratio (SNR) shows an increscent tendency with the coupling intensity increasing. These phenomena illustrate that clustering of cells may greatly enhance the sensitivity of Ca²⁺ signal, by which the biologic systems would probably improve their capability to respond to external stimulation.