Halliday David M, Rosenberg J R, Breeze P, Conway B A
Department of Electronics, University of York, UK.
IEEE Trans Biomed Eng. 2006 Jun;53(6):1056-66. doi: 10.1109/TBME.2006.873392.
A comparison of previously defined spike train syncrhonization indices is undertaken within a stochastic point process framework. The second-order cumulant density (covariance density) is shown to be common to all the indices. Simulation studies were used to investigate the sampling variability of a single index based on the second-order cumulant. The simulations used a paired motoneurone model and a paired regular spiking cortical neurone model. The sampling variability of spike trains generated under identical conditions from the paired motoneurone model varied from 50% to 160% of the estimated value. On theoretical grounds, and on the basis of simulated data a rate dependence is present in all synchronization indices. The application of coherence and pooled coherence estimates to the issue of synchronization indices is considered. This alternative frequency domain approach allows an arbitrary number of spike train pairs to be evaluated for statistically significant differences, and combined into a single population measure. The pooled coherence framework allows pooled time domain measures to be derived, application of this to the simulated data is illustrated. Data from the cortical neurone model is generated over a wide range of firing rates (1-250 spikes/s). The pooled coherence framework correctly characterizes the sampling variability as not significant over this wide operating range. The broader applicability of this approach to multielectrode array data is briefly discussed.
在随机点过程框架内，对先前定义的脉冲序列同步指数进行了比较。结果表明，所有指数的二阶累积密度（协方差密度）是相同的。使用模拟研究来调查基于二阶累积量的单个指数的采样变异性。模拟使用了配对运动神经元模型和配对规则发放皮层神经元模型。在相同条件下，配对运动神经元模型产生的脉冲序列的采样变异性在估计值的50%至160%之间变化。基于理论依据和模拟数据，所有同步指数都存在频率依赖性。考虑了将相干性和合并相干性估计应用于同步指数问题。这种频域方法允许对任意数量的脉冲序列对进行评估，以确定统计学上的显著差异，并合并为单个总体测量值。合并相干性框架允许推导合并时域测量值，并举例说明了将其应用于模拟数据的情况。皮层神经元模型的数据是在很宽的发放率范围（1-250个脉冲/秒）内生成的。合并相干性框架正确地将采样变异性表征为在这个宽操作范围内不显著。简要讨论了这种方法对多电极阵列数据的更广泛适用性。
