Working Memory Load Impact on Effective Connectivity: a Dynamic Causal Modeling Study

This study aims to examine the roles of the brain regions in working memory (WM) processing and the modulatory effects of WM load. Electroencephalogram (EEG) signals were recorded when participants perform a letter-version n-back task with three different levels of WM load. The directional causal connections between brain regions were estimated using Dynamic Causal Modeling (DCM). The directions and strengths of the connections were compared for different WM load conditions. The results showed a right-lateralized, backward-only connection pattern for the high WM load condition. The results also showed changes in the roles of the brain regions when the WM load increases. These findings of the modulatory effects of WM load may be utilized in measuring cognitive states, and designing adaptive automation in augmented cognition programs.