The neuroimmune pathway of high-altitude adaptation: influence of erythrocytes on attention networks through inflammation and the autonomic nervous system.

Introduction: Many studies have shown that the functional adaptation of immigrants to high-altitude is closely related to oxygen transport, inflammatory response and autonomic nervous system. However, it remains unclear how human attention changes in response to hypoxia-induced neurophysiological activity during high-altitude exposure. Methods: In the present study, we analyzed the relationship between hypoxic-induced neurophysiological responses and attention networks in 116 immigrants (3,680 m) using an attention network test to simultaneously record electroencephalogram and electrocardiogram in combination with specific routine blood markers. Results: Our analysis revealed that red blood cells exert an indirect influence on the three attention networks, mediated through inflammatory processes and heart rate variability. Discussion: The present study provides experimental evidence for the role of a neuroimmune pathway in determining human attention performance at high- altitude. Our findings have implications for understanding the complex interactions between physiological and neurocognitive processes in immigrants adapting to hypoxic environments.

Neurodynamics of Awareness Detection in Tibetan Immigrants: Evidence from Electroencephalography Analysis.

The psychological effects of long-term exposure to high-altitude environments have attracted great attention. These effects are usually attributed to the diminished cognitive resources due to high-altitude exposure. This study employed electroencephalography (EEG) to investigate the effects of exposure duration on awareness detection tasks. Neither reaction time nor accuracy showed the direct effects of the exposure duration, so did the model indexes obtained from drift diffusion model analysis. However, event-related potentials (ERP) analysis revealed that exposure duration was associated with changes in the visual awareness negativity (VAN) and the late positivity (LP) components, which in turn affected reaction time. Specifically, longer exposure durations were associated with lower VAN and higher LP, resulting in shorter reaction times and greater drift rate. In contrast to previous studies, the reverse relationship between VAN and LP may reflect a compensatory response to the reduced cognitive resources caused by high-altitude exposure. Additionally, increased LP and shorter reaction times with exposure duration may reflect a resistance to the high-altitude environment. We also conducted time-frequency analysis and found that theta power did not vary with exposure duration, suggesting that the reduction in cognitive resources remains stable in these individuals over time. Overall, our study provides new insights into the dynamic effects of high-altitude environments on awareness detection in the presence of reduced cognitive resources.

Association between the acceleration of access to visual awareness of grating orientation with higher heart rate at high-altitude.

Many studies have indicated a strong relationship between cardiac and brain activities, both of which are sensitive to high-altitude exposure. This study combined a consciousness access task and electrocardiograms (ECG) to uncover conscious awareness in response to high-altitude exposure and its relation to cardiac activity. When compared with the low-altitude groups, the behavioral results showed that the high-altitude participants shortened the time of access to visual awareness of grating orientation, which was accompanied by a faster heart rate, excluding the influence of pre-stimulus heart rate, extent of cardiac deceleration after presenting the stimulus, and task difficulty. Although there were post-stimulation cardiac deceleration and post-response acceleration at both high and low altitudes, a slight increase in heart rate after stimulation at high altitudes may indicate that participants at high altitudes could quickly readjust their attention to the target stimulus. More importantly, the drift diffusion model (DDM) was used to fit the access time distribution of all participants. These results suggest that shorter time at high altitudes might be due to the lower threshold, suggesting that less evidence in high-altitude participants was required to access visual consciousness. The participants' heart rates also negatively predicted the threshold through a hierarchical drift diffusion modeling (HDDM) regression. These findings imply that individuals with higher heart rates at high altitudes have a greater cognitive burden.

Oxygen Metabolism-induced Stress Response Underlies Heart-brain Interaction Governing Human Consciousness-breaking and Attention.

Neuroscientists have emphasized visceral influences on consciousness and attention, but the potential neurophysiological pathways remain under exploration. Here, we found two neurophysiological pathways of heart-brain interaction based on the relationship between oxygen-transport by red blood cells (RBCs) and consciousness/attention. To this end, we collected a dataset based on the routine physical examination, the breaking continuous flash suppression (b-CFS) paradigm, and an attention network test (ANT) in 140 immigrants under the hypoxic Tibetan environment. We combined electroencephalography and multilevel mediation analysis to investigate the relationship between RBC properties and consciousness/attention. The results showed that RBC function, via two independent neurophysiological pathways, not only triggered interoceptive re-representations in the insula and awareness connected to orienting attention but also induced an immune response corresponding to consciousness and executive control. Importantly, consciousness played a fundamental role in executive function which might be associated with the level of perceived stress. These results indicated the important role of oxygen-transport in heart-brain interactions, in which the related stress response affected consciousness and executive control. The findings provide new insights into the neurophysiological schema of heart-brain interactions.

Blood suPAR, Th1 and Th17 cell may serve as potential biomarkers for elderly sepsis management.

Although soluble urokinase plasminogen activator receptor (suPAR), T helper (Th)-1 and Th17 cells are separately reported to be dysregulated and correlate with disease severity in several infection-mediated diseases, fewer studies report their interaction and clinical value in sepsis management. Thus, this study aimed to investigate the correlation of blood suPAR with Th1 and Th17 cell proportion, as well as their diagnostic and prognostic value in elderly sepsis patients. Totally, 223 elderly sepsis patients were recruited. Serum suPAR was detected by enzyme-linked immunosorbent assay. Besides, Th1 and Th17 cell proportion from CD4+ T cells were determined by flow cytometry. For sepsis severity evaluation, Acute Physiology and Chronic Health Evaluation (APACHE) II score and the Sequential Organ Failure Assessment (SOFA) score were used. Moreover, survival profile within 28 days was documented. The mean value of suPAR, Th1 cell proportion and Th17 cell proportion was 27.5 ± 15.1 ng/mL, 15.3 ± 4.3% and 4.0 ± 2.3%, respectively. Furthermore, suPAR was positively correlated with Th1 cell proportion, Th17 cell proportion, IFN-γ, IL-17 and TNF-α. Meanwhile, suPAR was positively correlated with APACHE II score and SOFA score, so did Th17 cell proportion. Regarding their prognostic value, suPAR and Th17 cell proportion were superior to differ survivors from deaths than Th1 cell proportion. SuPAR positively correlates with Th1, Th17 cell proportion; and they correlate with increased disease severity and mortality risk in elderly sepsis patients.

Neuropsychological effect of working memory capacity on mental rotation under hypoxia environment.

High-altitude exposure induces the decline of spatial manipulation such as mental rotation which is limited by working memory capacity, but the underlying neuropsychological effect remains to be identified. We evaluated the mental rotation task and the contralateral delay activity (CDA) task under hypoxia environment using the event-related potential. When compared with the controls, the behavior response was slowed on two tasks in the high-altitude group. The declined mental rotation and the decreased working memory capacity were synchronously related to the amplitudes of P50 and CDA, respectively. The P50 during mental rotation was positively correlated to that of rotation-related negativity (RRN) component, so was with the CDA. Time-frequency analysis showed that the beta/alpha power in mental rotation and the theta/alpha/beta power in CDA were enhanced in the high-altitude group. The present study might suggest that the decline of working memory capacity induced poor performance of mental rotation, which may be derived from a bottom-up sensory gating deficit reflected by P50.

Spontaneous Activity in Primary Visual Cortex Relates to Visual Creativity.

Cognitive and neural processes underlying visual creativity have attracted substantial attention. The current research uses a critical time point analysis (CTPA) to examine how spontaneous activity in the primary visual area (PVA) is related to visual creativity. We acquired the functional magnetic resonance imaging (fMRI) data of 16 participants at the resting state and during performing a visual creative synthesis task. According to the CTPA, we then classified spontaneous activity in the PVA into critical time points (CTPs), which reflect the most useful and important functional meaning of the entire resting-state condition, and the remaining time points (RTPs). We constructed functional brain networks based on the brain activity at two different time points and then subsequently based on the brain activity at the task state in a separate manner. We explore the relationship between resting-state and task-fMRI (T-fMRI) functional brain networks. Our results found that: (1) the pattern of spontaneous activity in the PVA may associate with mental imagery, which plays an important role in visual creativity; (2) in comparison with the RTPs-based brain network, the CTP-network showed an increase in global efficiency and a decrease in local efficiency; (3) the regional integrated properties of the CTP-network could predict the integrated properties of the creative-network while the RTP-network could not. Thus, our findings indicated that spontaneous activity in the PVA at CTPs was associated with a visual creative task-evoked brain response. Our findings may provide an insight into how the visual cortex is related to visual creativity.