Department of Occupational and Environmental Health, the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Air Force Medical University, Xi'an, China.
Department of Radiology, Xijing Hospital, Air Force Medical University, Xi'an, China.
Brain Behav. 2020 Oct;10(10):e01656. doi: 10.1002/brb3.1656. Epub 2020 Sep 9.
High altitude (HA) exposure leads to cognitive impairment while the underlying mechanism is still unclear. Brain functional network is crucial for advanced functions, and its alteration is implicated in cognitive decline in multiple diseases. The aim of current study was to investigate the topological changes in HA-exposed brain functional network.
Based on Shaanxi-Tibet immigrant cohort, neuropsychological tests and resting-state functional MRI were applied to evaluate the participants' cognitive function and functional connection (FC) changes, respectively. GRETNA toolbox was used to construct the brain functional network. The gray matter was parcellated into 116 anatomically defined regions according to Automated Anatomical Labeling atlas. Subsequently, the mean time series for each of the 116 regions were extracted and computed for Pearson's correlation coefficients. The relation matrix was further processed and seen as brain functional network. Correlation between functional network changes and neuropsychological results was also examined.
The cognitive performance was impaired by HA exposure as indicated by neuropsychological test. HA exposure led to alterations of degree centrality and nodal efficiency in multiple brain regions. Moreover, two subnetworks were extracted in which the FCs significantly decreased after exposure. In addition, the alterations in FCs within above two subnetworks were significantly correlated with changes of memory and reaction time.
Our results suggest that HA exposure modulates the topological property of functional network and FCs of some important regions, which may impair the attention, perception, memory, motion ignition, and modulation processes, finally decreasing cognitive performance in neuropsychological tests.
高海拔（HA）暴露会导致认知障碍，但其潜在机制尚不清楚。大脑功能网络对于高级功能至关重要，其改变与多种疾病中的认知能力下降有关。本研究旨在探讨 HA 暴露后大脑功能网络的拓扑变化。
基于陕西-西藏移民队列，应用神经心理学测试和静息态功能磁共振成像分别评估参与者的认知功能和功能连接（FC）变化。GRETNA 工具箱用于构建大脑功能网络。将灰质根据自动解剖标记图谱划分为 116 个解剖定义的区域。随后，提取每个 116 个区域的平均时间序列并计算 Pearson 相关系数。关系矩阵进一步处理并视为大脑功能网络。还检查了功能网络变化与神经心理学结果之间的关系。
神经心理学测试表明，HA 暴露会导致认知表现受损。HA 暴露导致多个大脑区域的度中心性和节点效率发生变化。此外，还提取了两个子网，其中暴露后 FC 显著降低。此外，上述两个子网内的 FC 变化与记忆和反应时间的变化显著相关。
我们的结果表明，HA 暴露调节了功能网络的拓扑性质和一些重要区域的 FC，这可能会损害注意力、感知、记忆、运动启动和调节过程，最终降低神经心理学测试中的认知表现。
