Richter W, Ugurbil K, Georgopoulos A, Kim S G
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis 55455, USA.
Neuroreport. 1997 Dec 1;8(17):3697-702. doi: 10.1097/00001756-199712010-00008.
Time-resolved fMRI seeks to elucidate neuronal activity during a single execution of a mental task, which corresponds typically to a timescale of seconds. However, this is also the timescale of the hemodynamic response, which delays and blurs the signal in time. In order to distinguish the temporal characteristics of the neuronal activity from that of the hemodynamic response, which is often vaguely known, we recorded a set of fMRI time courses under conditions of a varying behavioral parameter, and correlated this parameter to the width of the fMRI response. For the task under investigation, the mental rotation of three-dimensional objects, we found that the activation in the parietal lobe is related to an aspect of the task that is described by the reaction time (for example, the very act of mental rotation), and not only to aspects of the task that are constant from trial to trial, such as the visual presentation at the beginning or the decision at the end of the task.
时间分辨功能磁共振成像旨在阐明在单次执行心理任务期间的神经元活动，这通常对应于秒级的时间尺度。然而，这也是血液动力学反应的时间尺度，它会在时间上延迟并模糊信号。为了区分神经元活动与通常了解甚少的血液动力学反应的时间特征，我们在行为参数变化的条件下记录了一组功能磁共振成像时间序列，并将该参数与功能磁共振成像反应的宽度相关联。对于所研究的任务，即三维物体的心理旋转，我们发现顶叶的激活与反应时间所描述的任务方面（例如，心理旋转的实际行为）相关，而不仅与每次试验中恒定的任务方面相关，例如任务开始时的视觉呈现或任务结束时的决策。
