Long-term high-altitude exposure influences task-related representations in visual working memory

Xiaohua Bao; Delong Zhang; Xiaoyan Li; Ming Liu; Hailin Ma

doi:10.3389/fneur.2023.1149623

Long-term high-altitude exposure influences task-related representations in visual working memory

Front Neurol. 2023 May 19:14:1149623. doi: 10.3389/fneur.2023.1149623. eCollection 2023.

Authors

Xiaohua Bao¹, Delong Zhang^{2

3}, Xiaoyan Li⁴, Ming Liu^{2

3}, Hailin Ma^{4

5}

Affiliations

¹ Faculty of Psychology, Tianjin Normal University, Tianjin, China.
² Plateau Brain Science Research Center, South China Normal University, Guangzhou, China.
³ Center for the Study of Applied Psychology, Key Laboratory of Mental Health and Cognitive Science of Guangdong Province, School of Psychology, South China Normal University, Guangzhou, China.
⁴ Plateau Brain Science Research Center, Tibet University, Lhasa, China.
⁵ Academy of Plateau Science and Sustainability, People's Government of Qinghai Province, Xining, China.

Abstract

Objective: Human working memory is impaired when individuals are exposed to high altitudes, however, whether the capacity of visual working memory is affected remains unclear. This study combined a lateralized change detection task and event-related potentials analysis to explore changes in visual working memory capacity among individuals who emigrated from a low-altitude environment to Tibet (a high-altitude environment).

Materials and methods: Thirty-five college students were recruited from Tibet University as the high-altitude (HA) group, and thirty-six low-altitude (LA) students were enrolled from South China Normal University (sea level) as the LA group. We measured participants' contralateral delay activity (CDA) under different memory loads.

Results: ERP component analysis showed that both the HA and LA groups reached an asymptote at memory load four. However, the contralateral and ipsilateral activity of the HA and LA groups shows different patterns. The results showed a significantly larger contralateral activity for the LA group than for the HA group at memory load one (p = 0.04, Cohen's d = 0.52) and load three (p = 0.02, Cohen's d = 0.61). Additionally, we found marginally larger contralateral activity at memory load four for the LA group (p = 0.06, Cohen's d = 0.47), but not at memory load two (p = 0.10) or load five (p = 0.12). No significant differences were observed for ipsilateral activity. In addition, we observed that the HA group performed larger ipsilateral activity than contralateral activity under each memory load, compared with the LA group.

Conclusion: These findings demonstrated that the attentional resource of long-term HA exposure is more captured by task-irrelevant information, potentially due to impaired inhibitory control, which makes it difficult for them to exclude the interference of task-irrelevant information.

Keywords: contralateral delay activity (CDA); high altitude; hypoxia; memory load; working memory.

Grants and funding

This research was supported by the Science and Technology Major Project of Tibetan Autonomous Region of China (grant numbers XZ202201ZD0001G and XZ202301YD0032C), the National Natural Science Foundation of China (grant numbers 32260212 and 82060588), the Scientific Development Funds for Local Region from the Chinese Government in 2022 (grant number XZ202201YD0018C), Key Science and Technology Project of Lhasa, Tibet (grant number LSKJ202309), and Science and Technology Project of Tibet Autonomous Region of China (grant number 2023ZYJM001).