Plateaus are important activity areas for human beings. The Qinghai Tibet Plateau has the largest area and population in the world. Previous studies suggested that long term exposure to high altitude environment affects physiological and cognitive functions. Abdominal breathing can reduce the influence of stress on the body, and improve cognitive function by regulating autonomic nerve system and cardiovascular system. In this study, a facial S1 S2 task combining event related potential (ERPs) technology was used to investigate the neural mechanism of impact underlying long term exposure to high altitudes hypoxia environment in the processing stage of perceptual organization and conflict monitoring function. Abdominal breathing intervention training was conducted for college students who had been exposed to high altitude for over 2 years for the purpose of improving their perceptual organization and conflict monitoring function, and to provide efficient and simple physical and mental intervention methods for people who migrate to the plateau.
This study includes two sub studies.
Study 1 adopts a cross sectional design. To explore the changes of perceptual organization and conflict monitoring function between a high altitude (HA) group and a sea level (SL) group, a facial S1 S2 task was adopted, which contains an occluded face photography (S1), and a complete face photography (S2). Differences in basic physiological parameters and ERPs data were compared between HA group, which comprised 26 college students who lived in high altitude areas (3658 m) for two years, and SL group, which comprised 26 college students who had never been to high altitude areas.
In Study 2, college students who had been living in high altitudes areas for two years were divided into an abdominal breathing intervention group (n=21) and a blank control group (n =23). Participants in the intervention group took abdominal breathing intervention (10 minutes per day, last for 21 consecutive days), and participants in the control group did not take any measures. Pre tests and post tests include some physiology indexes and a facial S1 S2 task, which is the same as Study 1.
The results of Study 1 revealed that the HA group had a higher pulse rate and diastolic blood pressure compared to the SL group, the oxygen saturation level was significantly lower than SL group. Additionally, compared with SL group, HA group showed significantly shortened latency of P1，the amplitude of the N170 was significantly increased, and the hemispheric asymmetry of the closure negativity (NCL) amplitude disappeared at high altitudes in the perceptual closure period. Furthermore，P1 latency was positively correlated with blood oxygen saturation and negatively correlated with heart rate and diastolic blood pressure.
The results of Study 2 showed that after the 21-day intervention, systolic pressure of the abdominal breathing intervention group was significantly lower, and the correct rate of facial S1-S2 task between the intervention group and the control group increased. The amplitude of the left temporal occipital region of N170 increased, the amplitudes of NCL in both groups were smaller in post-test. There was no significant difference in other physiological, behavioral and ERPs data between pre-test and post-test.
Taken together, the current findings suggest that long term residence in the plateau area leads to the decrease of blood oxygen saturation, the increase of heart rate and diastolic pressure, and the acceleration of nerve reaction activity in early visual perception stage, the immigrants recruit more psychological resources during the face structural encoding stage. They need to recruit contra lateral regions for compensating for their neurocognitive deficits to complete the perceptual closure process. The process of conflict monitoring is faster under long term high altitudes environment exposure. Abdominal breathing can reduce systolic pressure, the improvement of perceptual organization and conflict monitoring function is not apparent.