Characteristics of sustained attention impairment in individuals under simulated positive acceleration stress: separation effect of early and late stage cognitive processing.

Objective: This study aimed to investigate the mechanisms underlying impaired sustained attention under positive acceleration stress. Methods: We used a lower body negative pressure model to simulate positive acceleration stress and employed electroencephalography (EEG) to observe changes in brain function. Results: EEG results indicated that sustained attention exhibited a dissociation effect between early and late stages of processing following positive acceleration stress. The latency of the P2 component induced by non-target stimuli at the Cz electrode was significantly reduced under lower body negative pressure conditions, suggesting enhanced early perceptual processing of visual stimuli under acceleration stress. The amplitude of the P300 component induced by non-target stimuli at the Pz and Cz electrodes was significantly lower than that at baseline, suggesting impaired late-stage response selection processes. These findings indicate that individuals exhibit adaptive capacity under cerebral ischemia induced by acceleration stress, whereby enhanced early perceptual processing may partially compensate for impairments in the late-stage response selection phase. Conclusion: The dissociation between the early and late stages of visual attention processing reflects the body's adaptive adjustment ability in response to acceleration stress.