Differences in the hemodynamic response to event-related motor and visual paradigms as measured by near-infrared spectroscopy
Differences in the hemodynamic response to event-related motor and visual paradigms as measured by near-infrared spectroscopy
复制标题
DOI：
10.1016/s1053-8119(03)00311-2
复制
发表时间：
2003-09-01
期刊：
影响因子：
5.7
通讯作者：
Boas, DA
中科院分区：
文献类型：
--
作者：
Jasdzewski, G;Strangman, G;Boas, DA
目前的几种脑成像技术基于神经活动和血流动力学反应之间紧密耦合的假设。然而，这种神经血管耦合的性质尚不完全清楚。有一些证据表明，这些过程在神经活动开始时解耦，表现为脱氧血红蛋白（HbR）相对浓度的瞬间增加。然而，这种早期血流动力学反应功能的存在是有争议的，因为它的发现并不一致。近红外光谱（NIRS）可以量化人类在任务执行过程中血红蛋白（HbO(2)）和HbR的水平。我们在简单的运动和视觉任务中获得近红外光谱数据，使用快速呈现事件相关范式。我们的研究结果表明，快速的、与事件相关的近红外光谱可以提供可靠的血流动力学响应估计，而不会因低频信号成分而产生伪影，这与封闭设计的数据不同。在运动和视觉数据中，HbO(2)的增加发生在HbR下降之前，并且存在刺激后的低水平。我们的研究结果还表明，总血容量（HbT）在HbO(2)前下降，低于基线，这为神经血管模型提出了一个新的问题。我们没有在运动数据中发现早期脱氧，使用生理学上合理的差异路径长度因子值，但在视觉数据中确实发现了一个。我们认为，这种与功能性磁共振成像（fMRI）数据一致的差异可能归因于这些皮质中不同的毛细血管传输时间。(C) 2003 Elsevier Inc.版权所有。
Several current brain imaging techniques rest on the assumption of a tight coupling between neural activity and hemodynamic response. The nature of this neurovascular coupling, however, is not completely understood. There is some evidence for a decoupling of these processes at the onset of neural activity, which manifests itself as a momentary increase in the relative concentration of deoxyhemoglobin (HbR). The existence of this early component of the hemodynamic response function, however, is controversial, as it is inconsistently found. Near infrared spectroscopy (NIRS) allows quantification of levels of oxyhemoglobin (HbO(2)) and HbR during task performance in humans. We acquired NIRS data during performance of simple motor and visual tasks, using rapid-presentation event-related paradigms. Our results demonstrate that rapid, event-related NIRS can provide robust estimates of the hemodynamic response without artifacts due to low-frequency signal components, unlike data from blocked designs. In both the motor and visual data the onset of the increase in HbO(2) occurs before HbR decreases, and there is a poststimulus undershoot. Our results also show that total blood volume (HbT) drops before HbO(2) and undershoots baseline, raising a new issue for neurovascular models. We did not find early deoxygenation in the motor data using physiologically plausible values for the differential pathlength factor, but did find one in the visual data. We suggest that this difference, which is consistent with functional magnetic resonance imaging (fMRI) data, may be attributable to different capillary transit times in these cortices. (C) 2003 Elsevier Inc. All rights reserved.