The Functional And Structural Features Of Reward System In Internet Gaming Disorder

Internet has become an essential part of our daily life with the booming development of computers and Internet.However,excessive Internet use,especially Internet game-playing,could lead to various negative consequences,such as bad performance in school or work,family and social contacts,which was called Internet gaming disorder(IGD).IGD has increasingly raised wide-spread public health concerns and has been the spotlight of scientific research.Internet addiction has been suggested as the transition from initially voluntary Internet game-playing to eventual compulsive game-playing and dependence.And the reward system is thought to play a critical role in developing and maintaining addictive behavior.It has been linked to a high risk of relapse in addictive disorders.The present study was set to explore the neural mechanism of reward system in people with IGD and recreational Internet gaming users(RGU)—who play online games recreationally and escape transition to addiction.This study included 27 IGD and 43 RGU subjects.Results and conclusions were stated as below:Research one:The results of cue-reactivity-task-based functional magnetic resonance imaging(fMRI)showed that the IGD subjects exhibited higher activation in orbital frontal cortex(OFC)implicated in reward evaluation and lower activation in anterior cingulate cortex(ACC)implicated in executive control function,and precuneus,postcentral implicated in shifting attention and integrating information when compared to the RGU subjects.These results indicated the enhanced reward seeking and deficient control ability in individuals with IGD.Research two:The results of resting-state fMRI showed that the IGD subjects displayed aberrant functional connectivity in reward and executive control systems compared to the RGU subjects,such as enhanced connectivity in OFC,subdued connectivity in striatum and dorsolateral prefrontal cortex.And the connectivity between basal ganglia network and executive control network were reduced in the IGD subjects.These results demonstrated the enhanced reward seeking and diminished control ability in individuals with IGD.Research three:The results of structural MRI showed larger grey volume and smaller white volume in prefrontal cortex in the IGD subjects,which is involved in reward and executive control functions.These perpetual structural alteration were thought to be the underlying structural mechanism of enhanced reward seeking and deficient control ability in individuals with IGD.Taking all,the results from task fMRI,resting-state fMRI and structural MRI indicated that the IGD subjects exhibited dysfunction or structural abnormalities in some reward and executive control-related regions compared to the RGU subjects.Thus,the present study revealed the intense reward seeking and deficient executive control ability in IGD,which can explain why individuals with IGD develop dependence on game-playing while individuals with RGU can play online games recreationally and prevent the transition from voluntary game-playing to eventual IGD.