Coherence and short-term synchronization are insensitive to motor unit spike train nonstationarity.
Coherence and short-term synchronization are insensitive to motor unit spike train nonstationarity.
复制标题
相干性和短期同步对运动单位尖峰序列的非平稳性不敏感。
DOI：
10.1016/j.jneumeth.2009.08.011
复制
发表时间：
2010
影响因子：
3
通讯作者：
Griffin,L
中科院分区：
文献类型：
--
作者：
Terry,K;Griffin,L
电机单元以可变速率放电，从而产生本质上不稳定的尖峰序列。对于假设数据平稳性的信号分析技术，例如用于检测和量化相干性和短期同步 (STS) 的技术，非平稳性是导致不准确的潜在原因。如果相干性和 STS 指数对非平稳性水平敏感，那么将这些技术广泛应用于非平稳尖峰序列可能会降低之前和未来运动单位同步研究的有效性。为了解决这个问题，使用 Mann-Kendall 检验检查了在 2 分钟次最大等距任务期间记录在两只手部肌肉中的肌内 EMG 中获取的尖峰序列是否存在显着的非平稳性。然后针对所有生理尖峰序列对的平均尖峰序列非平稳强度进行相干性和 STS 指数的线性回归（n=92）。峰值相干性、相干指数、k′−1 和 CIS 用于量化同步性，而两个指数（StIn 和 StatAv）用于量化非平稳性。为了扩展本研究的范围和功效，使用集成火力模型创建了一个更大的模拟尖峰序列对池（n = 2520），其具有预定的同步和平稳强度以及与生理池非常接近的放电特性。生理和模拟对的回归表明，相干性、STS 及其指数对平稳性不敏感。因此，运动单位尖峰序列相干性和 STS 测量应该在稳定次最大任务典型的所有同步和非平稳性水平上保持稳健。此外，这一发现应该适用于具有相似同步性和非平稳性水平的所有尖峰序列，无论其来源如何。
Motor units discharge at variable rates and thereby produce spike trains that are inherently nonstationary. For signal analysis techniques that assume data stationarity, such as those for detecting and quantifying coherence and short-term synchronization (STS), nonstationarity presents a potential source of inaccuracy. If coherence and STS indices are sensitive to the level of nonstationarity, broad application of these techniques to nonstationary spike trains could diminish the validity of previous and future motor unit synchronization studies. To address this concern, spike trains taken from intramuscular EMG recorded in two hand muscles during a 2-min, submaximal isometric task were checked for significant nonstationarity using the Mann–Kendall test. Linear regressions were then performed for coherence and STS indices against the mean spike train nonstationarity strength for all physiological spike train pairs (n=92). Peak coherence, coherence index, k′−1, and CIS were used to quantify synchronization, whereas two indices (StIn and StatAv) were used to quantify nonstationarity. To extend the scope and power of this study, an integrate-to-fire model was used to create a much larger pool of simulated spike train pairs (n=2520) with predetermined synchronization and stationarity strengths and discharge properties that closely approximated those of the physiological pool. Regressions for both physiological and simulated pairs revealed that coherence, STS, and their indices were insensitive to stationarity. Therefore, motor unit spike train coherence and STS measurements should be robust across all synchronization and nonstationarity levels typical for steady submaximal tasks. Additionally, this finding should hold for all spike trains with similar levels of synchronization and nonstationarity, regardless of origin.
DOI：
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发表时间：
1983
期刊：
影响因子：
--
作者：
E. Gibson;E. Spelke;P. Mussen;J. Flavell;E. Markman
通讯作者：
E. Markman
学习和记忆的个体发生
DOI：
--
发表时间：
1979
期刊：
影响因子：
--
作者：
N. Spear;B. Campbell
通讯作者：
B. Campbell