Abstract：
The effects of hypoxia on brain function remain largely unknown. This study aimed to clarify this issue by visual-stimulated functional magnetic resonance imaging design. Twenty-three college students with a 30-d high-altitude exposure were tested before, 1 week and 3 months after returning to sea level. Brain functional magnetic resonance imaging and retinal electroretinogram were acquired. One week after returning to sea level, decreased blood oxygenation level dependent in the right lingual gyrus accompanied with increased blood oxygenation level dependent in the frontal cortex and insular cortex, and decreased amplitude of electroretinogram a-wave in right eye; moreover, the bilateral lingual gyri showed increased functional connectivity within the dorsal visual stream pathway, and the blood oxygenation level dependent signals in the right lingual gyrus showed positive correlation with right retinal electroretinogram a-wave. Three months after returning to sea level, the blood oxygenation level dependent signals recovered to normal level, while intensively increased blood oxygenation level dependent signals in a broad of brain regions and decreased retinal electroretinogram were also existed. In conclusion, hypoxic exposure has long-term effects on visual cortex, and the impaired retinal electroretinogram may contribute to it. The increased functional connectivity of dorsal stream may compensate for the decreased function of retinal photoreceptor cells to maintain normal visual function.
摘要：
缺氧对脑功能的影响在很大程度上仍然未知。本研究旨在通过视觉刺激功能磁共振成像设计来阐明这一问题。之前对23名大学生进行了30天的高空暴露测试，回到海平面后1周和3个月。获得脑功能磁共振成像和视网膜视网膜电图。回到海平面一周后，右舌回血氧合水平依赖性降低，额叶皮质和岛叶皮质血氧合水平依赖性升高，右眼视网膜电图a波的振幅降低；此外，双侧舌回显示背侧视觉流通路内的功能连通性增加，右舌回的血氧水平依赖性信号与右视网膜视网膜电图a波呈正相关。回到海平面三个月后，血氧水平依赖性信号恢复到正常水平，同时，在广泛的大脑区域中也存在强烈增加的血氧合水平依赖性信号和减少的视网膜视网膜电图。总之,低氧暴露对视觉皮层有长期影响，受损的视网膜视网膜电图可能是造成这种情况的原因。背侧流的功能连通性增加可以补偿视网膜感光细胞的功能下降，以维持正常的视觉功能。
