Dorsal and ventral striatal functional connectivity shift with the medial frontal gyrus in internet gaming disorder: Potential mechanisms underlying addictive engagement

BackgroundAnimal models suggest transitions from non-addictive to addictive behavioral engagement are associated with ventral-to-dorsal striatal shifts. However, few studies have examined such features in humans, especially in internet gaming disorder (IGD), a behavioral addiction. MethodsFour-hundred-and-eighteen subjects (174 with IGD; 244 with recreational game use (RGU)) were recruited. Resting-state fMRI data were collected and functional connectivity (FC) analyses were performed based on ventral and dorsal striatal seeds. Correlations and follow-up spectrum dynamic causal model (spDCM) analyses were performed to examine relationships between ventral/dorsal striatum to medial frontal gyrus (MFG) and IGD severity. Longitudinal data from 40 subjects (22 IGD; 18 RGU) were also analysed to investigate further. ResultsInteractions were observed between group (IGD, RGU) and striatal regions (ventral, dorsal). IGD relative to RGU subjects showed lower ventral-striatum-to-MFG (mostly involving supplementary motor area (SMA)) and higher dorsal-striatum-to-MFG functional connectivity. spDCM revealed that left dorsal-striatum-to-MFG connectivity was correlated with IGD severity. Longitudinal data further support for ventral-to-dorsal striatal MFG relationships in IGD. ConclusionsConsistent with animal models of substance addictions, ventral-to-dorsal striatal transitions in involvement coritico-striatal circuitry may underlie IGD and its severity. These findings suggest possible neurobiological mechanisms that may be targeted in treatments for IGD.