Impact of working memory training on brain network integration and neurotransmitter systems: a resting-state fMRI study

Working memory training (WMT) has been demonstrated to enhance cognitive performance, yet the underlying neural mechanisms remain insufficiently understood. Brain network connectivity, particularly as measured by the participation coefficient (PC), offers a valuable framework for elucidating these neural changes. This study investigated the effects of WMT on brain network connectivity, utilizing PC as a primary assessment of network integration and segregation. The relationship between WMT-induced changes in PC and the density of specific neurotransmitter receptors was examined. Seventy-six healthy participants were randomly assigned to either a WMT group or a control group. After 8 wks of training, the WMT group exhibited significant cognitive improvements, especially in near and far transfer tasks. These behavioral improvements were accompanied by specific changes in brain connectivity, including a reduction in PC within the sensorimotor network and node-specific alterations in the left prefrontal cortex, temporo-occipital-parietal junction, and parietal operculum. Moreover, changes in PC were significantly correlated with the density of dopamine D2 receptors, mu-opioid receptors, and metabotropic glutamate receptor 5. These findings enhance our understanding of how WMT influences cognitive function and brain network connectivity, highlighting the potential for targeting specific networks and neurotransmitter systems in cognitive training interventions.