Working memory capacity influences performance and brain networks: Evidence from effective connectivity analysis

The main goal of the present study was to investigate how individual differences in working-memory capacity influence the participants' performance and brain networks in a dual-task paradigm. An important function of working memory is to integrate incoming information into an appropriate cognitive model by using two executive functions — updating and inhibition. We hypothesized that individual variability in working-memory function (estimated using operation-span measure) may affect to differential reactivity to both performance and brain connectivity. EEG signals and reaction times were recorded during a dual task that combined n-back and flanker tasks. In these tasks, participants with high working-memory span scores showed a better performance than those with low span scores. This finding suggests that a group with high working memory capacity is more affected by the cognitive control network than a low capacity group, possibly because people with high span utilize more efficient brain network during dual or multitasking situations. These findings contribute to perceiving cognitive control network as an individual trait, which can reflect neural efficiency to allow augmented human cognition, as well as a significant predictor of brain-computer interface performance.