Department of Medical Psychology and Neuropsychology, University of Tilburg, Tilburg, The Netherlands; Department of Neurosurgery, St. Elisabeth Hospital, Tilburg, The Netherlands; Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands; Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands.
Hum Brain Mapp. 2014 Jan;35(1):340-52. doi: 10.1002/hbm.22180. Epub 2012 Sep 15.
Test-retest reliability of individual functional magnetic resonance imaging (fMRI) results is of importance in clinical practice and longitudinal experiments. While several studies have investigated reliability of task-induced motor network activation, less is known about the reliability of the task-free motor network. Here, we investigate the reproducibility of task-free fMRI, and compare it to motor task activity. Sixteen healthy subjects participated in this study with a test-retest interval of seven weeks. The task-free motor network was assessed with a univariate, seed-voxel-based correlation analysis. Reproducibility was tested by means of intraclass correlation (ICC) values and ratio of overlap. Higher ICC values and a better overlap were found for task fMRI as compared to task-free fMRI. Furthermore, ratio of overlap improved for task fMRI at higher thresholds, while it decreased for task-free fMRI, suggesting a less focal spatial pattern of the motor network during resting state. However, for both techniques the most active voxels were located in the primary motor cortex. This indicates that, just like task fMRI, task-free fMRI can properly identify critical brain areas for motor task performance. Although both fMRI techniques are able to detect the motor network, resting-state fMRI is less reliable than task fMRI.
个体功能磁共振成像（fMRI）结果的重测信度在临床实践和纵向实验中非常重要。虽然已经有几项研究调查了任务诱发运动网络激活的可靠性，但对于任务无关的运动网络的可靠性知之甚少。在这里，我们研究了任务无关 fMRI 的可重复性，并将其与运动任务活动进行了比较。16 名健康受试者参与了这项研究，测试-重测间隔为 7 周。使用单变量、种子体素相关分析评估任务无关的运动网络。通过组内相关系数（ICC）值和重叠率来测试可重复性。与任务无关的 fMRI 相比，任务 fMRI 的 ICC 值更高，重叠率更好。此外，任务 fMRI 的重叠率随着阈值的升高而提高，而任务无关的 fMRI 的重叠率则降低，这表明静息状态下运动网络的空间模式不那么集中。然而，对于这两种技术，最活跃的体素都位于初级运动皮层。这表明，与任务 fMRI 一样，任务无关 fMRI 可以正确识别运动任务表现的关键脑区。虽然两种 fMRI 技术都能够检测到运动网络，但静息状态 fMRI 的可靠性不如任务 fMRI。
