Default mode network hub disruption links problematic use of the Internet to brain network disorganization.
Nagara Takao, Naoya Oishi, Qi Dai, Lichang Yao, Sayaka Yoshimura, Mami Shibata, Morio Aki, Saki Akahori, Michael Spantios, Toshiya Murai, Hironobu Fujiwara
Comprehensive Psychiatry July 1, 2026 DOI: 10.1016/j.comppsych.2026.152725 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cross-sectional Peer reviewed |
|---|---|
| Sample size | 190 |
| Population | Healthy participants aged 20-69 years |
| Topics | Default mode network |
| Keywords | Graph theory Mediation analysis Network hubs Resting-State Functional MRI |
| Key findings | DMN functional connectivity substantially mediates the relationship between PUI severity and whole-brain network topology, with reduced DMN connectivity linked to deviation from optimal small-world organization. |
Abstract
Problematic Use of the Internet (PUI) has been associated with functional alterations in the default mode network (DMN), which contains critical hubs in the entire brain network. Previous studies have predicted that hub disruption leads to widespread network alterations; however, whether DMN functional connectivity mediates the relationship between PUI and global network topology remains unclear. This study examined whether DMN connectivity mediates PUI-related brain network topology. Resting-state functional magnetic resonance imaging data were collected from 190 healthy participants aged 20-69 years. DMN functional connectivity was assessed using region of interest (ROI)-to-ROI analyses with the Generalized Problematic Internet Use Scale-2 (GPIUS-2) as the primary predictor, controlling for age, sex, and mean framewise displacement. Graph-theoretical analyses quantified whole-brain network properties, including the clustering coefficient (Cp), shortest path length (Lp), global efficiency (Eg), and local efficiency (Eloc). Mediation analyses were performed to determine whether DMN functional connectivity mediates the relationship between GPIUS-2 and each metric. The functional connectivity values of all 17 DMN cluster pairs showed negative partial correlations with PUI severity (p-FDR < 0.05). Mean DMN connectivity strongly predicted global network topology (|ρ| = 0.36-0.41, all p-FDR < 1 × 10-6). Mediation analyses revealed that DMN functional connectivity substantially mediated the relationship between PUI severity and each metric (indirect effects: all p-FDR < 0.001; all direct effects p > 0.49). Reduced DMN connectivity was associated with decreased Cp and Eloc, increased Eg, and decreased Lp, indicating a deviation from optimal small-world organization. DMN hub connectivity serves as a critical neurobiological pathway through which the PUI influences the whole-brain network organization.
Comparable studies
Other cross-sectional and survey studies on default mode network, most cited first.