Controlling false positive rates in mass-multivariate tests for electromagnetic responses
Controlling false positive rates in mass-multivariate tests for electromagnetic responses
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DOI：
10.1016/j.neuroimage.2011.02.072
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发表时间：
2011-06-01
期刊：
影响因子：
5.7
通讯作者：
Friston, Karl J.
中科院分区：
文献类型：
--
作者：
Barnes, Gareth R.;Litvak, Vladimir;Friston, Karl J.
我们解决的问题，控制假阳性率在大规模多变量测试的电磁响应在紧凑的区域源空间。我们表明，基于传感器级多变量阈值（近似使用罗伊的工会交叉原则）的质量单变量阈值是过度保守的。然后，我们考虑一个Bonferroni校正源级测试的基础上，独特的铅场极值的数量。对于给定的源空间，列出了对应于最大值和最小值（对于每个偶极导联场）的传感器索引，并且唯一极值的数量由该列表中唯一对的数量给出。使用多变量波束形成器配方，我们验证了这种启发式对经验置换阈值的质量单变量和质量多变量测试（诱导和诱发反应）的各种源空间，使用模拟和真实的数据。我们还表明，同样的近似处理时，皮层流形（而不是体积）和质量多元最小范数的解决方案。我们证明，质量多变量框架并不限于测试一个单一的对比效果（参见罗伊的最大根），但也容纳多变量的影响（参见。Wilk的λ）。(C)2011 Elsevier Inc. All rights reserved.
We address the problem of controlling false positive rates in mass-multivariate tests for electromagnetic responses in compact regions of source space. We show that mass-univariate thresholds based on sensor level multivariate thresholds (approximated using Roy's union-intersection principle) are unduly conservative. We then consider a Bonferroni correction for source level tests based on the number of unique lead-field extrema. For a given source space, the sensor indices corresponding to the maxima and minima (for each dipolar lead field) are listed, and the number of unique extrema is given by the number of unique pairs in this list. Using a multivariate beamformer formulation, we validate this heuristic against empirical permutation thresholds for mass-univariate and mass-multivariate tests (of induced and evoked responses) for a variety of source spaces, using simulated and real data. We also show that the same approximations hold when dealing with a cortical manifold (rather than a volume) and for mass-multivariate minimum norm solutions. We demonstrate that the mass-multivariate framework is not restricted to tests on a single contrast of effects (cf, Roy's maximum root) but also accommodates multivariate effects (cf. Wilk's lambda). (C) 2011 Elsevier Inc. All rights reserved.