Intrinsic Functional Architecture Reflects Individual Differences in Passive Working Memory: An Exploratory Resting‐State fMRI Study

Passive working memory (WM) is rarely detectable because it is thought to rely less on persistent neural firing, leaving a minimal trace in ongoing brain activity. This elusive nature poses a major challenge for exploring its neural basis. While the activity-silent working memory (ASWM) framework proposes that such latent representations are maintained through transient reconfiguration in intrinsic functional connectivity, tracking these rapid dynamics via functional MRI remains methodologically difficult. Alternatively, investigating the brain's intrinsic functional architecture provides insights into the baseline "neural scaffolding" that predisposes individuals to successful passive WM. To explore this, we combined pre-task resting-state fMRI, structural MRI, and behavioral data from a sequential change-detection paradigm in 151 healthy adults. Functional connectivity-behavior associations revealed that individual differences in passive WM performance were significantly reflected by intrinsic connections among large-scale networks encompassing dorsal attention, control, and sensorimotor. Granger causality analyses further revealed a group-level temporal dependency pattern linking these functional systems. Furthermore, exploratory structural analyses suggested spatial convergence between uncorrected cortical-thickness associations and certain functionally identified sensorimotor nodes. Overall, this study adopts an exploratory approach to demonstrate that baseline intrinsic functional architecture-complemented by preliminary structural findings-is significantly associated with individual differences in passive WM.