Efficiency, power, and entropy in event-related fMRI with multiple trial types - Part 1: Theory
Efficiency, power, and entropy in event-related fMRI with multiple trial types - Part 1: Theory
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DOI：
10.1016/j.neuroimage.2003.09.030
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发表时间：
2004-01-01
期刊：
影响因子：
5.7
通讯作者：
Frank, LR
中科院分区：
文献类型：
--
作者：
Liu, TT;Frank, LR
功能磁共振成像（fMRI）实验的实验设计可以通过其估计效率（血流动力学响应函数（HRF）估计方差的度量）和检测能力（功能活动幅度估计方差的度量）来表征。先前的研究表明，对于单一感兴趣的试验类型的实验，效率和功率之间存在根本性的权衡。本文扩展了先前的工作，提出了多种试验类型实验中检测功率和估计效率之间关系的理论模型。结果表明，多重试验类型实验中存在的效率和功率之间的权衡在形式上与单次试验类型实验中观察到的相同。检查由于包含基函数展开和相关噪声假设而导致的与预测权衡的偏差。最后，引入条件熵作为设计随机性的度量，并提出熵与估计效率之间的经验关系。 (C) 2003 Elsevier Inc. 保留所有权利。
Experimental designs for functional magnetic resonance imaging (fMRI) experiments can be characterized by their estimation efficiency, which is a measure of the variance in the estimate of the hemodynamic response function (HRF), and their detection power, which is a measure of the variance in the estimate of the amplitude of functional activity. Previous studies have shown that there exists a fundamental trade-off between efficiency and power for experiments with a single trial type of interest. This paper extends the prior work by presenting a theoretical model for the relation between detection power and estimation efficiency in experiments with multiple trial types. It is shown that the trade-off between efficiency and power present in multiple-trial-type experiments is identical in form to that observed for single-trial-type experiments. Departures from the predicted trade-off due to the inclusion of basis function expansions and the assumption of correlated noise are examined. Finally, conditional entropy is introduced as measure for the randomness of a design, and an empirical relation between entropy and estimation efficiency is presented. (C) 2003 Elsevier Inc. All rights reserved.