Spatial and temporal differentiation of fMRI BOLD response in primary visual cortex of human brain during sustained visual simulation
Spatial and temporal differentiation of fMRI BOLD response in primary visual cortex of human brain during sustained visual simulation
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DOI：
10.1002/mrm.1910390404
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发表时间：
1998-04-01
影响因子：
3.3
通讯作者：
Ugurbil, K
中科院分区：
文献类型：
--
作者：
Chen, W;Zhu, XH;Ugurbil, K
几个小组使用功能磁共振成像研究了持续视觉刺激期间的血氧水平依赖性（BOLD）反应，结论有争议。在高（4特斯拉）磁场强度下，使用8赫兹的闪烁护目镜研究了这个问题。结果表明，初级视觉皮层的整体BOLD反应在视觉刺激开始后出现初始超调，在视觉刺激结束后出现过调。然而，在初始和终端瞬态响应之间，一个显著且积极的BOLD响应保持不变。初级视觉皮层的颞叶BOLD反应具有空间依赖性。图像中被识别为引流静脉的区域显示出成比例的更大的初始和终末瞬态响应，而没有此类血管且主要与实质相关的区域则表现出更不随时间变化的BOLD响应。这些结果表明，在持续的视觉刺激过程中，初级视觉皮层维持了BOLD效应以及脑血流量和脑代谢耗氧量之间的解耦，并且BOLD效应的时间特征具有空间依赖性。
The blood oxygenation level dependent (BOLD) response during sustained visual stimulation has been studied by several groups using fMRI with controversial conclusions. This issue was investigated for the human brain at high (4 Tesla) magnetic field strength using a flashing goggle at 8 Hz. The results demonstrate that the overall BOLD response in the primary visual cortex has an initial overshoot after the onset of visual stimulation and an undershoot after the termination of visual stimulation. A significant and positive BOLD response, however, remains constant between the initial and terminal transient responses. The temporal BOLD responses in the primary visual cortex were spatially dependent. The regions identified as draining veins in images displayed proportionately larger initial and terminal transient responses, whereas regions devoid of such vessels and associated mainly with parenchyma exhibited a more time-independent BOLD response. These results reveal that the BOLD effect and, presumably, the uncoupling between cerebral blood flow and cerebral metabolic rate of oxygen consumption, are maintained in the primary visual cortex during sustained visual stimulation, and the temporal characteristics of the BOLD effect are spatially dependent.