Nonparametric statistical testing of coherence differences
Nonparametric statistical testing of coherence differences
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DOI：
10.1016/j.jneumeth.2007.02.011
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发表时间：
2007-06-15
影响因子：
3
通讯作者：
Fries, Pascal
中科院分区：
文献类型：
--
作者：
Maris, Eric;Schoffelen, Jan-Mathijs;Fries, Pascal
神经科学中的许多重要问题都是关于神经元或神经元群之间的相互作用。这些相互作用通常通过相干性来量化，相干性是量化两个信号表现出一致相位关系的程度的频率索引度量。在本文中，我们考虑在两个实验条件下观察到的相干值之间的差异的统计检验。我们特别注意的问题（1）不平等的样本大小和（2）的事实，通常是在大量的频率箱和大量的神经元或神经元组之间的一致性评估（多重比较问题）。我们表明，非参数统计检验为这两个问题提供了令人信服的和优雅的解决方案。我们还表明，这些测试允许将生物制药动机的限制在测试统计量，这可能会大大增加测试的灵敏度。最后，我们解释了为什么非参数检验在形式上是正确的。这意味着，我们制定了一个零假设（相同的概率分布在不同的实验条件下），并表明，非参数检验控制在此零假设下的误报率。所提出的方法通过分析在关于皮质-脊髓相干性的研究中收集的数据来说明[Schoffelen JM，Oostenveld R，Fries P. Neuronal coherence as a mechanism of effective corticosporinal interaction. Science 2005;308（5718）：111-3]。(c)2007 Elsevier B. V.保留所有权利。
Many important questions in neuroscience are about interactions between neurons or neuronal groups. These interactions are often quantified by coherence, which is a frequency-indexed measure that quantifies the extent to which two signals exhibit a consistent phase relation. In this paper, we consider the statistical testing of the difference between coherence values observed in two experimental conditions. We pay special attention to problems induced by (1) unequal sample sizes and (2) the fact that coherence is typically evaluated at a large number of frequency bins and between large numbers of pairs of neurons or neuronal groups (the multiple comparisons problem). We show that nonparametric statistical tests provide convincing and elegant solutions for both problems. We also show that these tests allow to incorporate biophysically motivated constraints in the test statistic, which may drastically increase the sensitivity of the test. Finally, we explain why the nonparametric test is formally correct. This means that we formulate a null hypothesis (identical probability distribution in the different experimental conditions) and show that the nonparametric test controls the false alarm rate under this null hypothesis. The proposed methodology is illustrated by analyses of data collected in a study on cortico-spinal coherence [Schoffelen JM, Oostenveld R, Fries P. Neuronal coherence as a mechanism of effective corticospinal interaction. Science 2005;308(5718):111-3]. (c) 2007 Elsevier B.V. All rights reserved.