细胞膜离子单通道电流重构的计算机仿真.PDF

218 2011 ，47 （16） Computer Engineering and Applications 计算机工程与应用 细胞膜离子单通道电流重构的计算机仿真 乔晓艳，吴晋芝，耿晓勇，董有尔 QIAO Xiaoyan ，WU Jinzhi ，Geng Xiaoyong ，DONG You’er 山西大学 物理电子工程学院，太原 030006 College of Physics and Electronics Engineering ，Shanxi University ，Taiyuan 030006 ，China QIAO Xiaoyan ，WU Jinzhi ，Geng Xiaoyong ，et al.Computer simulation of current restoration for ionic single-channel. Computer Engineering and Applications ，2011 ，47 （16）：218-220. Abstract ：Single ion channel current signal of cell membrane is a stochastic ionic current in the order of picoampere （PA ）. The background noise always dominates in the patch-clamp recordings.At present ，the threshold detection method is used to restore channel current signal.However ，the current threshold need be setted artificially ，and this method cannot work satisfacto- rily when signal-to-noise ratio is lower.Hidden Markov Model （HMM ）is adopted for restoring the ion-channel current and es- timating parameters of the model.HMM on ion-channel is described and analyzed.Iterative algorithm based Baum-Welch is used for training HMM and estimating model parameters.Viterbi algorithm is adopted for restoring the best state sequence of ion-channel currents.Comparing HMM with the threshold detection method ，the algorithm based HMM is simulated under the different transition probability and signal-to-noise ratio.The experimental results have shown that compared with the threshold detector ，HMM has strong ability of anti-noise ，high restoration precision ，and fast convergent rate under the low signal-to- noise ratio.Moreover ，the restored error appears mainly on the mutational points of the current signal. Key words ：ionic single-channel ；threshold detector method ；Hidden Markov Model （HMM ）；current restoration 摘 要：细胞膜离子单通道电流十分微弱（PA 级），用膜片钳技术测量离子电流往往淹没在强噪声背景中。目前，采用阈值检测 方法恢复通道电流信号。但是，通道开放和关闭的电流阈值需要人为设定，并且阈值法在较低信噪比时失效。采用隐马尔可夫 模型（HMM ）重构离子单通道电流并估计模型参数。对离子通道HMM 进行描述和分析；运用Baum-Wel