EEG source connectivity analysis reveals working-memory related load effect on regional characteristics

Accurate assessment of mental workload (MWL) is crucial for ensuring safety in both production and daily life. Consequently, there has been a growing focus on understanding the neural mechanisms underlying MWL. However, most of the existing studies concentrate on task-specific neural mechanisms, which limits the ability to generalize MWL assessments across different tasks. To investigate task-independent MWL-related brain dynamics at regional level, we designed two working memory (WM) experiments (i.e., mental arithmetic and N-back tasks), each with two difficulty levels corresponding to the low and high MWL. The collected electroencephalogram (EEG) data were projected onto the source space first to construct cortex-level functional network. Subsequent analysis was conducted on functional connectivity (FC) and degree centrality (DC) across two MWL levels. The results revealed complex yet similar distribution patterns of significant differences in θ-band and α-band FCs in both tasks. Additionally, changes in degree centrality indicated the frontal, parietal and occipital regions were crucial to task-independent MWL evaluation. Overall, these findings offer novel insights into the neural mechanisms of task-independent MWL.