Raz Jonathan, Zheng Hui, Ombao Hernando, Turetsky Bruce
Division of Biostatistics, University of Pennsylvania, Philadelphia, PA 19104, USA.
Neuroimage. 2003 Jun;19(2 Pt 1):226-32. doi: 10.1016/s1053-8119(03)00115-0.
Statistical parametric mapping (SPM) analysis of fMRI data requires specifying correctly the temporal and spatial noise covariance structure. This is a difficult if not impossible task. When these assumptions are not satisfied, statistical inference can be invalid or inefficient. Permutation tests are free of strong assumptions on the distribution of signal noise. We propose permutation tests of fMRI data based on experimental randomization of the stimulus sequences. Smooth hemodynamic response curves are estimated using quadratic B-splines. We study fMRI data obtained from event-related potential (ERP) oddball paradigm. Tests of two-tone and three-tone stimulus sequences are conducted to illustrate the application of the proposed method. Comparisons of the SPM and proposed method show that a permutation test is more specific and less susceptible to artifacts.
功能磁共振成像（fMRI）数据的统计参数映射（SPM）分析需要正确指定时间和空间噪声协方差结构。这即便不是一项不可能完成的任务，也是一项艰巨的任务。当这些假设不成立时，统计推断可能无效或效率低下。置换检验对信号噪声分布没有强假设。我们基于刺激序列的实验随机化提出了fMRI数据的置换检验。使用二次B样条估计平滑的血液动力学响应曲线。我们研究了从事件相关电位（ERP）奇偶数范式获得的fMRI数据。进行了双音和三音刺激序列的测试以说明所提出方法的应用。SPM与所提出方法的比较表明，置换检验更具特异性且更不易受到伪影的影响。
