Abnormal effective connectivity of default mode network subsystems affects depressive symptoms and sleep disturbances in adolescents with internet gaming disorder

Studies have demonstrated that Internet gaming disorder (IGD) was associated with sleep and psychological disorders. The default mode network (DMN) is not a unitary system, but rather is composed of smaller and distinct functional subsystems that interact with each other. We aimed to assess the functional relevance of these subsystems and the neural underpinnings of clinical symptoms in IGD. We recruited 47 IGD adolescents and 56 healthy controls, and examined their effective connectivity (EC) from three DMN subsystems by using dynamic causal modelling (DCM), including midline core network (PCC-aMPFC core DMN), medial temporal subsystem (MTL-DMN), and dorsal medial prefrontal subsystem (dMPFC-DMN). The relationships between neuroimaging findings, anxiety/depression and sleep disturbances were assessed through a mediation model. Finally, Leave-one-out cross-validation was used to investigate whether neural response could predict accompanying symptoms of IGD. The IGD group showed increased EC from PCC-aMPFC core DMN to MTL-DMN and increased self-connection of lateral temporal cortex (LTC) compared to the control group. The EC from anterior medial prefrontal cortex (aMPFC) to posterior inferior parietal lobule (pIPL) mediated the relationship between depression and sleep disturbances in IGD. Moreover, increased EC from aMPFC to pIPL could predict sleep disturbances of IGD adolescents. This study emphasized the aberrant effective connectivity of different functional subsystems of DMN and revealed the neural correlates of accompanying symptoms in IGD adolescents. These findings suggested DMN subsystems-derived indicators could help to identify accompanying symptoms of IGD and could be explored as a target for neuromodulation interventions in future studies. Not applicable.