Aerobic exercise modulates EEG microstates under distinct mental workload

It is well-established that aerobic exercise modulates mental workload (MWL) and enhances cognitive function. However, existing studies predominantly rely on indirect behavioral results, and direct neural evidence is insufficient. Therefore, it is essential to investigate how exercise modulates neural activity during cognitive tasks. In recent years, electroencephalogram (EEG) microstate analysis has emerged as a critical tool for investigating the spatiotemporal dynamics of brain electrophysiological activity. The four canonical microstate classes have been extensively studied, and their parameters are proven to correlate with MWL. In this study, participants performed N-back tasks with two MWL levels (low: 1-back; high: 3-back) following two counterbalanced exercise conditions: aerobic exercise (ES) and rest (RS). Behavioral and EEG data from 49 participants were collected during the tasks. The typical microstate parameters (Occurrences/OCC, Time Coverage/TC and Mean Duration/MD) and transition characteristics were compared. The results showed that high MWL levels increased MD of class C but decreased OCC of class D. Exercise significantly improved subjective perception of MWL during tasks and promoted transitions to class D, increasing its TC and MD. These findings suggest that exercise enhance cognitive-related microstate dynamics potentially, thereby mitigating MWL, given that class D has been associated with activations in parietal and frontal cortical regions. These findings of this study provide further insights into the potential neural mechanisms by which aerobic exercise modulates MWL.