Combined machine learning and functional magnetic resonance imaging allows individualized prediction of high-altitude induced psychomotor impairment: The role of neural functionality in putamen and pallidum

Abstract

At high-altitude, hypoxia together with other physiological stressors, including low temperature, ultraviolet rays and dehydration, may lead to a decline in cognitive function (1). Previous studies have proved that acute and chronic hypoxia exposure during highaltitude expedition cause impairment in working memory, learning ability, attention and concentration. Recently, according to a previous study based on Tibet immigration population in China, two-year hypoxia Summary Hypoxia exposure during high-altitude expedition cause psychomotor impairment. Neuroimaging studies indicated that the impairment may be significantly associated with neuron loss and decreased regional homogeneity (ReHo) in several brain regions, suggesting the neural functionality in these regions may be utilized to predict psychomotor impairment under exposure. In this study, 69 subjects come from Shaanxi-Tibet immigrant cohort. Reaction time (RT) tasks were performed to measure the subject's psychomotor function before and after 2-year high-altitude exposure. For each individual, the RT differences between pre-exposure and post-exposure were calculated, which were referred to as "targets" in model establishment. Rs-fMRI data were acquired at the same time with RT tasks. For each individual, the map of ReHo alteration was generated, from which the patterns would be recognized. A pattern recognition procedure was utilized to train and test the predictive models. Two different cross-validation strategies were utilized to evaluate the model performance: leave-one-out cross-validation and four-fold cross-validation. For the models displaying significant R 2 and MSE, weight maps were built. As a result, the predictive models were able to decode the changes of simple and recognition reaction time from the alterations of brain activation under the exposure. The regions with highest contributions to the predictions were bilateral putamen and bilateral pallidum, suggesting that predictions were mainly based on the patterns concentrated in these regions. This study was a proof of concept study designed to examine whether individual-level psychomotor impairment under highaltitude exposure could be predicted by a combination of pattern recognition approach and neuroimaging data.

Intermittent hypoxic conditioning restores neurological dysfunction of mice induced by long‐term hypoxia

“… 28 , 29 , 30 In addition, the hypoxic treatment times in this study were 0, 1, 3, 7, and 14 d, which was based on the conversion of human life expectancy from mice to human life expectancy, which is about 2 weeks for mice at the 14 d. 31 , 32 It has been reported in previous studies that people in the plain areas had cognitive dysfunctions after living on the plateau for 1–2 years. 33 , 34 In this study, neurological dysfunction was found in the H7d and H14d groups of mice, which is consistent with the results reported in previous studies. Therefore, the oxygen concentration (13% O 2 ) and hypoxia treatment time (14 d) selected in this study were appropriate for the study of brain injuries induced by altitude hypoxia.…”

The human brain in a high altitude natural environment: A review

“…In soldiers who had garrisoned the frontiers in the Qinghai-Tibet Plateau for 2 years, the regional homogeneity (ReHo) of neuronal activity ( Chen et al, 2016a ), voxel-mirrored homo-topic connectivity in the bilateral visual cortex ( Chen et al, 2016b ), and amplitude of low-frequency fluctuations (ALFF) of resting-state neuronal activity ( Zhang et al, 2017 ) were investigated. In the sea level college students who had immigrated to a plateau for 1 and 2 years, ReHo of neuronal activity was also studied ( Chen X. et al, 2017 ; Wang et al, 2017 ), and further study on these students suggested that ReHo of neuronal activity in the bilateral putamen and bilateral pallidum can predict psychomotor impairment due to HA exposure ( Chen et al, 2019b ).…”

Suggestive evidence of CYP4F2 gene polymorphisms with HAPE susceptibility in the Chinese Han population

“…The increase of vascular permeability and vasoconstriction of diastolic imbalance is a crucial mechanism of acute high-altitude sickness. The bronchoalveolar fluid of patients with HAPE contains a large number of alveolar macrophages and detectable amounts of inflammatory factors such as leukotriene-B4 and other lipoxygenase products of arachidonic acid metabolism [ 9 , 10 ].…”