Effect of basal conditions on the magnitude and dynamics of the blood oxygenation level-dependent fMRI response
Effect of basal conditions on the magnitude and dynamics of the blood oxygenation level-dependent fMRI response
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DOI：
10.1097/00004647-200209000-00002
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发表时间：
2002-09-01
影响因子：
6.3
通讯作者：
Kim, SG
中科院分区：
文献类型：
--
作者：
Cohen, ER;Ugurbil, K;Kim, SG
基础脑血流量（CBF）对人类功能性血流动力学反应的幅度和动力学的影响尚未得到充分研究。因此，在不同的基础条件下：低碳酸血症，正常碳酸血症和高碳酸血症，在7-T磁场中，使用血氧水平依赖性（BOLD）功能磁共振成像（fMRI）测量人类受试者对视觉刺激的血液动力学反应。通过吸入5%二氧化碳气体混合物诱导高碳酸血症，通过过度通气产生低碳酸血症。随着fMRI基线信号从低碳酸血症水平到高碳酸血症水平随呼出CO2线性增加，BOLD对视觉刺激的反应幅度线性下降。视觉诱发BOLD反应的动力学指标（起始时间、半峰全宽和达峰时间）随基础fMRI信号和呼气末CO2水平线性增加。基础CBF水平，调制的动脉分压的二氧化碳显着影响的幅度和动力学的BOLD反应引起的神经活动。这些结果表明，在比较不同的生理或药理学状态下刺激诱导的fMRI反应时，应谨慎。
The effect of the basal cerebral blood flow (CBF) on both the magnitude and dynamics of the functional hemodynamic response in humans has not been fully investigated. Thus, the hemodynamic response to visual stimulation was measured using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in human subjects in a 7-T magnetic field under different basal conditions: hypocapnia, normocapnia, and hypercapnia. Hypercapnia was induced by inhalation of a 5% carbon dioxide gas mixture and hypocapnia was produced by hyperventilation. As the fMRI baseline signal increased linearly with expired CO2 from hypocapnic to hypercapnic levels, the magnitude of the BOLD response to visual stimulation decreased linearly. Measures of the dynamics of the visually evoked BOLD response (onset time, full-width-at-half-maximum, and time-to-peak) increased linearly with the basal fMRI signal and the end-tidal CO2 level. The basal CBF level, modulated by the arterial partial pressure of CO2 significantly affects both the magnitude and dynamics of the BOLD response induced by neural activity. These results suggest that caution should be exercised when comparing stimulus-induced fMRI responses under different physiologic or pharmacologic states.