Ito H, Takahashi K, Hatazawa J, Kim S G, Kanno I
Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita, Japan.
J Cereb Blood Flow Metab. 2001 May;21(5):608-12. doi: 10.1097/00004647-200105000-00015.
The hemodynamic mechanism of increase in cerebral blood flow (CBF) during neural activation has not been elucidated in humans. In the current study, changes in both regional CBF and cerebral blood volume (CBV) during visual stimulation in humans were investigated. Cerebral blood flow and CBV were measured by positron emission tomography using H(2)(15)O and (11)CO, respectively, at rest and during 2-Hz and 8-Hz photic flicker stimulation in each of 10 subjects. Changes in CBF in the primary visual cortex were 16% +/- 16% and 68% +/- 20% for the visual stimulation of 2 Hz and 8 Hz, respectively. The changes in CBV were 10% +/- 13% and 21% +/- 5% for 2-Hz and 8-Hz stimulation, respectively. Significant differences between changes in CBF and CBV were observed for visual stimulation of 8 Hz. The relation between CBF and CBV values during rest and visual stimulation was CBV = 0.88CBF(0.30). This indicates that when the increase in CBF during neural activation is great, that increase is caused primarily by the increase in vascular blood velocity rather than by the increase in CBV. This observation is consistent with reported findings obtained during hypercapnia.
在人类中，神经激活期间脑血流量（CBF）增加的血流动力学机制尚未阐明。在本研究中，对人类视觉刺激期间局部CBF和脑血容量（CBV）的变化进行了研究。分别使用H(2)(15)O和(11)CO通过正电子发射断层扫描在10名受试者的静息状态以及2 Hz和8 Hz光闪烁刺激期间测量脑血流量和CBV。初级视觉皮层中CBF的变化在2 Hz和8 Hz视觉刺激下分别为16%±16%和68%±20%。CBV的变化在2 Hz和8 Hz刺激下分别为10%±13%和21%±5%。在8 Hz视觉刺激下，观察到CBF和CBV变化之间存在显著差异。静息和视觉刺激期间CBF与CBV值之间的关系为CBV = 0.88CBF(0.30)。这表明当神经激活期间CBF的增加很大时，这种增加主要是由血管血流速度的增加引起的，而不是由CBV的增加引起的。这一观察结果与高碳酸血症期间报告的发现一致。
