Dorsal and ventral striatal functional connectivity shifts play a potential role in internet gaming disorder

Animal 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 proposed behavioral addiction. We recruited 418 subjects (174 with IGD; 244 with recreational game use (RGU)). Resting-state fMRI data were collected and functional connectivity 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 the ventral/dorsal striatum and middle frontal gyrus (MFG). Longitudinal data were also analysed to investigate changes over time. 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 within IGD and RGU groups found greater dorsal striatal connectivity with the MFG in IGD versus RGU subjects. These findings suggest similar ventral-to-dorsal striatal shifts may operate in IGD and traditional addictions.