Exploring the impact of chronic high-altitude exposure on visual spatial attention using the ERP approach

Introduction: Previous studies have reported the slowing of reaction times to attentionally demanding tasks due to a reduction in cognitive resource as a result of chronic high-altitude exposure. However, it is still largely unknown whether this reaction slowness can be attributed to the attentional allocation change and/or response patterns. Methods: To clarify this issue, this study investigated attention-related (N2pc and N2cc) and response-related (MP and RAP) event-related potentials (ERPs) to identify the performance of a visual search task by individuals who had lived in high-altitude areas for three years compared with those living at sea level. Results: This study showed that the reaction times in response to a visual search task were significantly longer in the high-altitude subjects than in the sea level subjects. Corresponding to this behavioral observation, we found a significantly lower N2pc amplitude and a larger N2cc amplitude in the high-altitude subjects, suggesting a reduction in spatial attention allocation to the target (N2pc) in these subjects, indicating they need to work harder to preclude cross-talk between response selection and attention direction (N2cc). Moreover, we also discovered higher MP amplitudes and longer RAP latencies in the high-altitude subjects, which further indicated that these subjects were slower and required greater cortical activation while preparing and executing correctly selected responses (MP and RAP). Conclusion: Nevertheless, this study collectively provided new insights into the attention reaction slowness from high-altitude exposure.