Lindquist Martin A, Meng Loh Ji, Atlas Lauren Y, Wager Tor D
Department of Statistics, Columbia University, New York, NY 10027, USA.
Neuroimage. 2009 Mar;45(1 Suppl):S187-98. doi: 10.1016/j.neuroimage.2008.10.065. Epub 2008 Nov 21.
Most brain research to date have focused on studying the amplitude of evoked fMRI responses, though there has recently been an increased interest in measuring onset, peak latency and duration of the responses as well. A number of modeling procedures provide measures of the latency and duration of fMRI responses. In this work we compare several techniques that vary in their assumptions, model complexity, and interpretation. For each method, we introduce methods for estimating amplitude, peak latency, and duration and for performing inference in a multi-subject fMRI setting. We then assess the techniques' relative sensitivity and their propensity for mis-attributing task effects on one parameter (e.g., duration) to another (e.g., amplitude). Finally, we introduce methods for quantifying model misspecification and assessing bias and power-loss related to the choice of model. Overall, the results show that it is surprisingly difficult to accurately recover true task-evoked changes in BOLD signal and that there are substantial differences among models in terms of power, bias and parameter confusability. Because virtually all fMRI studies in cognitive and affective neuroscience employ these models, the results bear on the interpretation of hemodynamic response estimates across a wide variety of psychological and neuroscientific studies.
迄今为止,大多数脑研究都集中在研究诱发功能磁共振成像(fMRI)反应的幅度上,不过最近人们对测量反应的起始、峰值潜伏期和持续时间也越来越感兴趣。一些建模程序提供了fMRI反应潜伏期和持续时间的测量方法。在这项工作中,我们比较了几种在假设、模型复杂性和解释方面存在差异的技术。对于每种方法,我们介绍了估计幅度、峰值潜伏期和持续时间以及在多受试者fMRI设置中进行推断的方法。然后,我们评估这些技术的相对敏感性以及它们将一个参数(例如持续时间)上的任务效应错误归因于另一个参数(例如幅度)的倾向。最后,我们介绍了量化模型错误指定以及评估与模型选择相关的偏差和功率损失(效能损失)的方法。总体而言,结果表明,准确恢复真实的任务诱发的血氧水平依赖(BOLD)信号变化出奇地困难,并且在效能、偏差和参数混淆性方面,不同模型之间存在很大差异。由于认知和情感神经科学中几乎所有的fMRI研究都采用了这些模型,因此这些结果关系到广泛的心理学和神经科学研究中血流动力学反应估计的解释。