Neumann Jane, Lohmann Gabriele, Zysset Stefan, von Cramon D Yves
Max-Planck-Institute of Cognitive Neuroscience, Stephanstrasse 1a, D-04103 Leipzig, Germany.
Neuroimage. 2003 Jul;19(3):784-96. doi: 10.1016/s1053-8119(03)00177-0.
In this paper we investigate the within-subject variability of dynamical aspects of the BOLD response obtained in a series of fMRI sessions several days apart. Five different parameters describing the temporal behavior of trial-averaged time courses, such as time-to-peak and time-to-onset, were estimated and analyzed with respect to their variability across nine sessions. Results show that small variances of the estimated parameters can be found, provided that the analysis is restricted to voxels activated in all individual sessions. Among the investigated parameters, time-to-peak shows the most stable behavior. These results were obtained using two different analysis methods, the estimation of the parameters directly from trial-averaged time courses and fitting trial-averaged time courses to an assumed hemodynamic response function. Both methods yield comparable results.
在本文中，我们研究了在相隔数天的一系列功能磁共振成像（fMRI）实验中获得的血氧水平依赖（BOLD）反应动态方面的受试者内变异性。估计并分析了描述试验平均时间进程时间行为的五个不同参数，如峰值时间和起始时间，并研究了它们在九个实验中的变异性。结果表明，如果分析仅限于在所有个体实验中均被激活的体素，则估计参数的方差较小。在所研究的参数中，峰值时间表现出最稳定的行为。这些结果是使用两种不同的分析方法获得的，一种是直接从试验平均时间进程中估计参数，另一种是将试验平均时间进程拟合到假定的血液动力学反应函数。两种方法得出的结果相当。
