Objective:To investigate the neural mechanism of long-term exposure to high altitudes environment on the processing stage of perceptual closure.Methods:A cross-sectional study was conducted. Thirty college students who first entered the plateau area (at an altitude of 3 658 m) and had lived in high-altitude areas for two years were selected as high altitude group (HA group), and 29 college students matched in age, gender and education level who had never been to the plateau area were selected as sea level group (SL group). The differences of basic physiological parameters were compared between the two groups.The face pairwise comparison paradigm was applied in the subjects of the two groups and the differences between the two groups were compared by event-related potentials (ERPs) technology. SPSS 22.0 software was used for statistical analysis, and the mean ± standard deviation was used for statistical description. Independent sample t test was used for comparison of physiological data between the two groups, and repeated measurement variance analysis was used for ERP data. Results:The physiological results revealed that the HA group had a higher pulse rate((86.71±10.82)/min, (75.97±11.28)/min ; t=-3.19, P=0.002) and diastolic blood pressure than the SL group ((75.93±9.19)mmHg, ( 68.59±11.42) mmHg ; t=-3.20, P=0.002). The oxygen saturation level was significantly lower than that of SL group ((90.77±2.25)%, (98.31±1.56) %) ; t=14.00, P<0.001). In the face pairwise comparison paradigm test, the main effect of P1 latency of ERP was significant.Compared with SL group, HA group showed significantly shortened latency of P1 ((105.10±15.59) ms, (128.35±14.40)ms, P<0.001). The main effect of group of N170 amplitude was significant, HA group was larger than that of SL group((-7.57±3.83) μV, ( -5.11±3.26) μV, P=0.005). The interaction effect between group and hemisphere of NCL amplitude was significant ( F(1, 57)=9.72, P=0.003). Simple effect test showed that the amplitude on the right hemisphere of SL group was significantly larger than that on the left hemisphere((0.46±1.31) μV), (1.16±1.33) μV ). The latency of P1 was significantly correlated with heart rate( r=-0.46, P<0.01), oxygen saturation level( r=0.64, P<0.01) and diastolic blood pressure( r=-0.26, P=0.049). Conclusion:After long-term exposure to high altitude, the neural response related to early visual perception is faster. More psychological resources are recruited during the face structural encoding stage. Contra-lateral compensating effect appeares in the stage of perceptual closure.

Objective:To explore the neutral mechanism of influence of long-term exposure to high altitude hypoxia environment on the processing stage of conflict inhibition.Methods:Differences in the electroencephalogram during a 2-1 mapping Stroop task were compared between a high-altitude (HA) group ( n=20) who lived in a high-altitude area (3 650 m) for two years, and a low-altitude (LA) group ( n=20) who had never visited high-altitude areas. Results:The HA group had a higher pulse rate ((82.0±9.7)/min vs (74.0±11.3)/min) and lower oxygen saturation level ((90.7±2.8)% vs (97.4±1.1)%) compared with LA group.Behavior data showed that the reaction time (RT) in congruent (CO) condition was shorter than that in stimulus incogruent (SI) condition, and the RT in SI condition was shorter than that in RI condition ((707.91±70.33)ms vs (753.76±72.96)ms vs (803.88±73.21)ms); accuracy(ACC) rate in SI condition was higher than CO condition, and the ACC in CO condition was higher than RI condition((96.35±2.91)% vs (95.90±2.83)% vs (91.55±5.22)%). And the response conflict effect was larger than the stimulus conflict effect((49.76±33.90) vs (23.60±30.20)). The differences were all statistically significant (all P<0.01). In SI condition, the RT of HA group was longer than LA group((730.43±60.50)ms vs (777.09±78.23)ms) ( P<0.05). As for the EEG, the amplitude of P2((6.18±0.62)μV vs (3.21±0.62)μV) and N450((1.39±1.48)μV vs (5.91±1.48)μV) component of the HA group were higher those that of the LA group.The amplitude of N450 at P4 electrode site was larger than that at P3 electrode site in HA group((2.26±1.34)μV vs (0.62±1.43)μV). The differences were all statistically significant (all P<0.05). Conclusion:Long-term exposure to high altitude hypoxia environment affects the early stage of stimulus perception and task retrieval, as well as the conflict monitoring in later stage of stimulus and response conflict.The HA group need compensation of right parietal to complete the conflict monitoring of stimulus and response conflict.