Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.16.253385v1?rss=1 Authors: Dong, G.-H. Abstract: Background: 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 behavioral addiction. Methods: Four-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. Results: Interactions 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. Conclusions: Consistent 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. Copy rights belong to original authors. Visit the link for more info