School of Optometry, Indiana University, Bloomington, 47405, USA.
Sci Rep. 2020 Sep 29;10(1):16051. doi: 10.1038/s41598-020-73032-0.
When retinal activity is increased by exposure to dynamic visual stimuli, blood vessels dilate and the flow of blood within vessels increases to meet the oxygen and glucose demands of the neurons. This relationship is termed 'neurovascular coupling' and it is critical for regulating control of the human retinal vasculature. In this study, we used a recently developed technique based on a dual-beam adaptive optics scanning laser ophthalmoscope to measure changes in red blood cell velocities, vessel diameter, and flow in interconnected small parafoveal retinal vessels (< 50 µm) of nine healthy participants. A full-field flicker stimulus was presented onto the retina to induce a vascular response to neural activity. Flicker stimulation increased blood velocity, vessel diameter, and therefore flow in arterioles, capillaries, and venules in all nine subjects. ANOVA and post hoc t-test showed significant increases in velocity and flow in arterioles and venules. These measurements indicate that the mechanism of neurovascular coupling systematically affects the vascular response in small retinal vessels in order to maintain hemodynamic regulation in the retina when exposed to visual stimulation, in our case flicker. Our findings may provide insight into future investigations on the impairments of neurovascular coupling from vascular diseases such as diabetic mellitus.
当视网膜受到动态视觉刺激时，其活跃度会增加，血管会扩张，血管内的血液流动会增加，以满足神经元的氧气和葡萄糖需求。这种关系被称为“神经血管耦合”，对于调节人类视网膜血管的控制至关重要。在这项研究中，我们使用了一种基于双光束自适应光学扫描激光检眼镜的新技术，来测量九名健康参与者的小旁中心视网膜(<50µm)互连小血管中红细胞速度、血管直径和血流的变化。全视野闪烁刺激被呈现在视网膜上，以诱导对神经活动的血管反应。闪烁刺激增加了所有九名受试者的小动脉、毛细血管和小静脉中的血流速度、血管直径，从而增加了血流。方差分析和事后 t 检验显示，小动脉和小静脉中的速度和流量都有显著增加。这些测量结果表明，神经血管耦合机制系统地影响小视网膜血管的血管反应，以在暴露于视觉刺激（在我们的情况下是闪烁）时维持视网膜的血液动力学调节。我们的发现可能为未来研究糖尿病等血管疾病引起的神经血管耦合损伤提供启示。
