Dynamic Top-down Configuration by the Core Control System During Working Memory

The central executive system (CES) may be the most fundamental yet least understood component of working memory. There is an ongoing debate about which brain regions underlie the top-down regulation of CES during working memory tasks. The neural substrates and regulatory mechanisms of CES remain controversial partly because few previous studies have been focused on comprehensive activation and deactivation joint analysis on all systems involved in all working memory stages, which have shown increasing importance in depicting the neural configuration of working memory. To address these questions, we conducted a functional magnetic resonance imaging study using a comprehensive activation-deactivation-behavior joint analysis to examine the dynamics of a set of cortical systems in healthy subjects performing a modified Sternberg working memory task which was designed to push the subjects to their limit in working memory and to introduce strong demands for regulation by CES. We assessed brain activity during various working memory stages using general linear model and single trial-stage estimation, and examined the relationship between the single trial-stage activity and behavioral performance. We identified constant activation in the dorsal anterior cingulate cortex and anterior insula in all working memory stages and its relationship with performance, which indicate the CES's neural basis. We also identified dynamic configuration of multiple downstream systems in different working memory stages, which indicates the regulation mechanism of CES.