Impaired brain networks functional connectivity after acute mild hypoxia

Abstract

This study aimed to analyze the changes in brain networks functional connectivity of pilots exposed to simulated hypoxia using resting-state functional magnetic resonance imaging (fMRI). A total of 35 healthy male pilots exposed to 14.5% oxygen concentration (corresponding to an altitude of 3000 m) underwent resting-state fMRI scans. The independent component analysis (ICA) approach was used to analyze changes in the resting-state brain networks functional connectivity of pilots after hypoxic exposure, and 9 common components in brain functional networks were identified. In the functional connections that showed significant group differences, linear regression was used to examine the association between functional connectivity and clinical characteristics. The brain networks functional connectivity after hypoxia exposure decreased significantly, including the left frontoparietal network and visual network 1-area, left frontoparietal network and visual network 2-area, right frontoparietal network and visual network 2-area, dorsal attention network and ventral attention network, dorsal attention network and auditory network, and ventral attention network and visual network 1-area. We found no correlation between the altered functional connectivity and arterial oxygen saturation level. Our findings provide insights into the mechanisms underlying hypoxia-induced cognitive impairment in pilots.Abbreviations: AN = attention network, AudN = auditory network, DMN = default mode network, fMRI = functional magnetic resonance imaging, FPN = frontal parietal network, GIFT = group ICA of fMRI toolbox, ICA = independent component analysis, SpO 2 = peripheral oxygen saturation, VN = visual network, WM = working memory.

The impact of wearing a KN95 face mask on human brain function: evidence from resting state functional magnetic resonance imaging

“…This difference suggested that the hypoxic environment may alter the patterns of interaction among large-scale brain networks compared to normal ventilation status, resulting in broad changes in the neuro function. This founding was consistent with the results of RS-fMRI in previous studies on acute hypoxia and obstructive sleep apnea hypopnea syndrome (6,7). Similar effect was also reported in a recent study, Haller et al found that wearing masks may change the patterns functional connectivity with the salience network (18).…”

“…This phenomenon was also confirmed by a large number of subsequent studies (4,5). Acute hypoxia and obstructive sleep apnea hypopnea syndrome lead to changes in spontaneous neural activity of the brain in the resting state (6,7). Previous studies have shown that changes in the composition of inhaled air flow and the increase of CO 2 concentration elevated the blood flow in cerebral arteries and affected the blood supply of the cortex (8).…”