Aguirre G K, Zarahn E, D'esposito M
Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, 19104-4283, USA.
Neuroimage. 1998 Nov;8(4):360-9. doi: 10.1006/nimg.1998.0369.
Cerebral hemodynamic responses to brief periods of neural activity are delayed and dispersed in time. The specific shape of these responses is of some importance to the design and analysis of blood oxygenation level-dependent (BOLD), functional magnetic resonance imaging (fMRI) experiments. Using fMRI scanning, we examine here the characteristics and variability of hemodynamic responses from the central sulcus in human subjects during an event-related, simple reaction time task. Specifically, we determine the contribution of subject, day, and scanning session (within a day) to variability in the shape of evoked hemodynamic response. We find that while there is significant and substantial variability in the shape of responses collected across subjects, responses collected during multiple scans within a single subject are less variable. The results are discussed in terms of the impact of response variability upon sensitivity and specificity of analyses of event-related fMRI designs.
大脑对短暂神经活动期的血流动力学反应在时间上延迟且分散。这些反应的具体形态对于基于血氧水平依赖（BOLD）的功能磁共振成像（fMRI）实验的设计和分析具有一定重要性。在此，我们使用fMRI扫描，研究人类受试者在与事件相关的简单反应时间任务期间中央沟血流动力学反应的特征和变异性。具体而言，我们确定受试者、日期和扫描时段（在一天内）对诱发血流动力学反应形态变异性的贡献。我们发现，虽然不同受试者采集的反应形态存在显著且实质性的变异性，但同一受试者多次扫描期间采集的反应变异性较小。我们根据反应变异性对事件相关fMRI设计分析的敏感性和特异性的影响来讨论这些结果。
