Converging evidence has identified cognitive control deficits in internet gaming disorder (IGD). Recently, mounting evidence had revealed that resting state functional connectivity (RSFC) and structural connectivity of frontostriatal circuits could modulate cognitive control in healthy individuals. Unfortunately, relatively little is known about the thoroughly circuit-level characterization of the frontostriatal pathways (both the dorsal and ventral striatum) during resting-state and their association with cognitive control in IGD. In the current study, the differences of striatum volume and RSFC networks were investigated between 43 young IGD individuals and 44 healthy controls. Meanwhile, cognitive control deficits were assessed by Stroop task performances. The neuroimaging findings were then correlated with the Stroop task behaviors. In IGD subjects, we demonstrated an increased volume of right caudate and nucleus accumbens (NAc) as well as reduced RSFC strength of dorsal prefrontal cortex (DLPFC)-caudate and orbitofrontal cortex (OFC)-NAc. NAc volumes were positively correlated with internet addiction test scores in IGD. The caudate volume and DLPFC-caudate RSFC was correlated with the impaired cognitive control (more incongruent errors in Stroop task) in IGD. Consistent with substance use disorder (SUD) findings, we detected striatum volume and frontostriatal circuits RSFC differences between IGD and healthy controls, which provided evidence of some degree of the similarity between IGD and SUD. More importantly, the cognitive control deficits in IGD were correlated with the reduced frontostrital RSFC strength. It is hoped that our results could shed insight on the neurobiological mechanisms of IGD and suggest potential novel therapeutic targets for treatment.

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The critical roles of frontostriatal circuits had been revealed in addiction. With regard to young smokers, the implication of frontostriatal circuits resting-state functional connectivity (RSFC) in smoking behaviors and cognitive control deficits remains unclear. In this study, the volume of striatum subsets, i.e., caudate, putamen, and nucleus accumbens, and corresponding RSFC differences were investigated between young smokers (n1  = 60) and nonsmokers (n2  = 60), which were then correlated with cigarette smoking measures, such as pack_years-cumulative effect of smoking, Fagerström Test for Nicotine Dependence (FTND)-severity of nicotine addiction, Questionnaire on Smoking Urges (QSU)-craving state, and Stroop task performances. Additionally, mediation analysis was carried out to test whether the frontostriatal RSFC mediates the relationship between striatum morphometry and cognitive control behaviors in young smokers when applicable. We revealed increased volume of right caudate and reduced RSFC between caudate and dorsolateral prefrontal cortex (DLPFC), orbitofrontal cortex in young smokers. Significant positive correlation between right caudate volume and QSU as well as negative correlation between anterior cingulate cortex-right caudate RSFC and FTND were detected in young smokers. More importantly, DLPFC-caudate RSFC strength mediated the relationship between caudate volume and incongruent errors during Stroop task in young smokers. Our results demonstrated that young smokers showed abnormal interactions within frontostriatal circuits, which were associated with smoking behaviors and cognitive control impairments. It is hoped that our study focusing on frontostriatal circuits could provide new insights into the neural correlates and potential novel therapeutic targets for treatment of young smokers. Hum Brain Mapp 37:2013-2026, 2016. © 2016 Wiley Periodicals, Inc.