Objective Accurate speed perception is crucial for tasks such as man-controlled rendezvous and docking,and teleoperation of space manipulator.Therefore,it is necessary to conduct in-orbit experiments to explore the influence of long-term spaceflight on human speed perception characteristics.Methods The Time-to-Collision(TTC)paradigm was selected to develop experimental software,using a tablet computer for stimulus presentation.Human speed perception characteristics were evaluated based on the subjects'keystroke response data on the keyboard.Through ground-based experiments,the usability and reliability of the paradigm were explored,and the gravity internal model effect was quantitatively analyzed.Through in-orbit experiments on space station tasks,the influence of long-term spaceflight on human speed perception characteristics was further investigated.Results Under the 1G environment on the ground,the TTC paradigm has a high test-retest reliability(r>0.8),and indicators such as average deviation rate and absolute value of average deviation rate show no practice effect.In addition,ground experiments found that compared to vertical upward movement,vertical downward movement is estimated to be faster(i.e.,keystroke time is advanced),showing the existence of the gravity internal model effect.In the microgravity environment of spaceflight,there are no significant differences in average deviation rate and absolute value of average deviation rate among three stages(pre-flight,in-flight,post-flight)and seven tests,indicating that no obvious changes in astronauts'speed perception ability were found at the existing test time points and paradigms.However,the gravity internal model effect(difference between vertical downward and vertical upward)showed a trend of fading in the early stage of astronauts entering orbit.Conclusion Based on the computer screen TTC estimation paradigm,no significant changes in human speed perception ability were found during long-term spaceflight,but microgravity may weaken the human brain's gravity internal model.

On plateaus,the low-oxygen and low-pressure environment is likely to lead to cognitive impairments,negatively impacting individuals newly exposed to high altitudes.This paper reviews how high-altitude environments impair cognitive functions and explores protective strategies in terms of oxygen-enriched and pressurization technologies,neuroregulation techniques,and approaches to endogenous protection.It is recommended that future research focus on personalized cognitive protection and training,the construction of integrated protection systems based on multi-technology convergence,and the investigation of long-term effectiveness and sustainability.These efforts are expected to result in more comprehensive strategies for cognitive protection and enhancement in high-altitude operations.

Objective To explore the network structure of anxiety,depression and sleep among individuals under long-term high-altitude exposure.Methods A total of 303 subjects who had resided at high altitudes for more than 6 months on end were selected.The insomnia severity index(ISI),patient health questionnaire(PHQ-9),and generalized anxiety disorder scale(GAD-7)were employed to assess insomnia,depression and anxiety before network analysis was conducted to identify the central and bridge nodes in the symptom network.Results The incidence of moderate or severe depression,anxiety and insomnia were 38.9％[95％confidence interval(CI):33.4％-44.5％],23.1％(95％CI:18.3％-27.9％),and 18.5％(95％CI:14.1％-22.9％),respectively."Noticeability of sleep problems by others"had the highest expected influence centrality,followed by"sleep maintenance""uncontrollable worry""restlessness"and"sleep problems".Five bridge symptoms were identified:"sad mood""sleep problems""restlessness""feeling afraid"and"trouble relaxing".Conclusion Sleep-related symptoms play a crucial role in the overall network structure,serving as both central and bridge nodes.Additionally,the"feeling down or depressed"acts as a bridge node and holds importance in the comorbidity network of anxiety and depression.Targeting these key symptoms through intervention and prevention strategies may improve the psychological well-being of individuals with long-term residence in high-altitude regions.