Detection power, estimation efficiency, and predictability in event-related fMRI
Detection power, estimation efficiency, and predictability in event-related fMRI
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DOI：
10.1006/nimg.2000.0728
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发表时间：
2001-04-01
期刊：
影响因子：
5.7
通讯作者：
Buxton, RB
中科院分区：
文献类型：
--
作者：
Liu, TT;Frank, LR;Buxton, RB
事件相关功能磁共振成像的实验设计可以通过其检测功率（检测激活的能力的量度）和其估计效率（估计血液动力学响应的形状的能力的量度）来表征。随机设计提供最大的估计效率，但检测功率差，而块设计提供良好的检测功率的最小估计效率的成本。周期性单次试验设计在这两个标准下都很差。我们在这里提出了一个理论模型的估计效率和检测功率之间的关系，并表明所观察到的效率和功率之间的权衡是根本的。使用该模型，我们探索半随机设计，提供中间的效率和功率之间的权衡的属性。这些设计可以同时实现随机化设计的估计效率和区组设计的检测能力，但代价是实验长度增加不到2倍。实验设计也可以通过其可预测性来表征，这是一种规避混淆（如习惯化和预期）的能力的度量。我们研究了检测功率，估计效率和可预测性之间的关系，并表明，可预测性的小幅度增加可以提供显着的收益，检测功率只有轻微的估计效率下降。(C)北京：科学出版社.
Experimental designs for event-related functional magnetic resonance imaging can be characterized by both their detection power, a measure of the ability to detect an activation, and their estimation efficiency, a measure of the ability to estimate the shape of the hemodynamic response. Randomized designs offer maximum estimation efficiency but poor detection power, while block designs offer good detection power at the cost of minimum estimation efficiency. Periodic single-trial designs are poor by both criteria. We present here a theoretical model of the relation between estimation efficiency and detection power and show that the observed trade-off between efficiency and power is fundamental. Using the model, we explore the properties of semirandom designs that offer intermediate trade-offs between efficiency and power. These designs can simultaneously achieve the estimation efficiency of randomized designs and the detection power of block designs at the cost of increasing the length of an experiment by less than a factor of 2. Experimental designs can also be characterized by their predictability, a measure of the ability to circumvent confounds such as habituation and anticipation. We examine the relation between detection power, estimation efficiency, and predictability and show that small increases in predictability can offer significant gains in detection power with only a minor decrease in estimation efficiency. (C) 2001 Academic Press.