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Aims: To identify subgroups of people with internet gaming disorder (IGD) based on addiction‐related resting‐state functional connectivity and how these subgroups show different clinical correlates and responses to treatment. Design: Secondary analysis of two functional magnetic resonance imaging (fMRI) data sets. Setting: Zhejiang province and Beijing, China. Participants: One hundred and sixty‐nine IGD and 147 control subjects. Measurements k‐Means algorithmic and support‐vector machine‐learning approaches were used to identify subgroups of IGD subjects. These groups were examined with respect to assessments of craving, behavioral activation and inhibition, emotional regulation, cue–reactivity and guessing‐related measures. Findings Two groups of subjects with IGD were identified and defined by distinct patterns of connectivity in brain networks previously implicated in addictions: subgroup 1 ('craving‐related subgroup') and subgroup 2 ('mixed psychological subgroup'). Clustering IGD on this basis enabled the development of diagnostic classifiers with high sensitivity and specificity for IGD subgroups in 10‐fold validation (n = 218) and out‐of‐sample replication (n = 98) data sets. Subgroup 1 is characterized by high craving scores, cue–reactivity during fMRI and responsiveness to a craving behavioral intervention therapy. Subgroup 2 is characterized by high craving, behavioral inhibition and activations scores, non‐adaptive emotion‐regulation strategies and guessing‐task fMRI measures. Subgroups 1 and 2 showed largely opposite functional–connectivity patterns in overlapping networks. Conclusions: There appear to be two subgroups of people with internet gaming disorder, each associated with differing patterns of brain functional connectivity and distinct clinical symptom profiles and gender compositions. [ABSTRACT FROM AUTHOR]

Cognitive, functional, and structural brain factors involving frontal executive and striatal reward networks have been implicated in Internet gaming disorder (IGD). However, frontostriatal network connectivity and its association with addiction severity are poorly understood in IGD. Resting-state fMRI data from 337 subjects (130 with IGD, 207 with recreational game use [RGU]) were collected. Striatal-cortical communications were measured with resting-state functional connectivity (FC) using coherent spontaneous fluctuations in the blood-oxygenation-level-dependent fMRI signal. Correlations were calculated between FC measures and IGD-related assessments (addiction severity and craving scores). Decreased FC was predominantly observed in IGD subjects, with IGD subjects showing decreased FC between the putamen and superior frontal gyrus (SFG), middle frontal gyrus (MFG), and inferior frontal gyrus (IFG) and the ventral striatum and IFG, superior temporal gyrus, and MFG. Disorder severity and craving scores were negatively correlated with FC between striatal and frontal brain regions. Associations between diminished FC in corticostriatal circuitry and clinical features (IGD craving, severity) suggest potential therapeutic targets for neuromodulation treatments. The extent to which frontostriatal circuits involving executive control over reward processes may be altered to treat IGD warrants additional study. [ABSTRACT FROM AUTHOR]

Cross‐sectional studies have suggested that functional heterogeneity within the striatum in individuals with addictive behaviours may involve the transition from ventral to dorsal partitions; however, due to limitations of the cross‐sectional design, whether the contribution of this transition to addiction was confused by individual differences remains unclear, especially for internet gaming disorder (IGD). Longitudinal functional magnetic resonance imaging (fMRI) data from 22 IGD subjects and 18 healthy controls were collected at baseline and more than 6 months later. We examined the connectivity features of subregions within the striatum between these two scans. Based on the results, we further performed dynamic causal modelling to explore the directional effect between regions and used these key features for data classification in machine learning to test the replicability of the results. Compared with controls, IGD subjects exhibited decreased functional connectivity between the left dorsal striatum (putamen) and the left insula, whereas connectivity between the right ventral striatum (nucleus accumbens [Nacc]) and the left insula was relatively stable over time. An inhibitory effective connectivity from the left putamen to the right Nacc was found in IGD subjects during the follow‐up scan. Using the above features, the classification accuracy of the training model developed with the follow‐up was better than that of the model based on the initial scan. Persistent IGD status was accompanied by a switch in the locus of control within the striatum, which provided new insights into association between IGD and drug addiction. [ABSTRACT FROM AUTHOR]

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. In order to shed light on the underlying neural mechanisms of internet gaming disorder (IGD), Dong et al collected longitudinal resting-state fMRI data from participants with IGD or those who partake in recreational game use. They demonstrated that, consistent with animal models of addiction, dorsal and ventral striatal functional connectivity shifts appeared to play a potential mechanistic role in IGD. [ABSTRACT FROM AUTHOR]

Internet gaming disorder (IGD) is included in the DSM-5 as a provisional diagnosis. Whether IGD should be regarded as a disorder and, if so, how it should be defined and thresholded have generated considerable debate. In the current study, machine learning was used, based on regional and interregional brain features. Resting-state data from 374 subjects (including 148 IGD subjects with DSM-5 scores ≥5 and 93 IGD subjects with DSM-5 scores ≥6) were collected, and multivariate pattern analysis (MVPA) was employed to classify IGD from recreational game use (RGU) subjects based on regional brain features (ReHo) and communication between brain regions (functional connectivity; FC). Permutation tests were used to assess classifier performance. The results demonstrated that when using DSM-5 scores ≥5 as the inclusion criteria for IGD subjects, MVPA could not differentiate IGD subjects from RGU, whether based on ReHo or FC features or by using different templates. MVPA could differentiate IGD subjects from RGU better than expected by chance when using DSM-5 scores ≥6 with both ReHo and FC features. The brain regions involved in the default mode network and executive control network and the cerebellum exhibited high discriminative power during classification. The current findings challenge the current IGD diagnostic criteria thresholding proposed in the DSM-5, suggesting that more stringent criteria may be needed for diagnosing IGD. The findings suggest that brain regions involved in the default mode network and executive control network relate importantly to the core criteria for IGD. [ABSTRACT FROM AUTHOR]

Background: Studies have revealed that sleep disturbances lead to an increased risk of Internet gaming disorder (IGD). However, the neural underpinnings of this feature remain unknown. Exploring this issue would be valuable in understanding the relationship between sleep and psychiatric disorders.Methods: Given the impact of sleep on reward circuitry, we examined nucleus accumbens (NAcc) and hippocampal resting-state functional connectivity (rsFC) differences between 41 IGD subjects and 59 healthy controls. Significant connections were determined and used to examine correlations with clinical variables. Finally, we explored the relationship between neuroimaging findings, IGD severity and sleep disturbances through a mediation model.Results: We observed the connection deviation between the hippocampus and a wide range of cerebral cortexes in IGD subjects, including the prefrontal, parietal and temporal lobes. More importantly, the right posterior hippocampus (pHIP)-left caudate rsFC was positively correlated with both the Pittsburgh Sleep Quality Index (PSQI) and Internet Addiction Test scores and mediated the relationship between the two. For the NAcc, a difference between groups was only observed in the rsFC between the shell partition of the NAcc and the inferior orbitofrontal cortex, but this connectivity was not related to the PSQI score.Conclusions: IGD subjects showed a wide range of abnormal connections in the hippocampus, involving memory, reward motivation, and cognitive control. Here we emphasized the potential of the hippocampus in studying sleep disturbances in IGD, especially the coupling between the pHIP and caudate nucleus, which could provide novel insight into how sleep interacts with motivational systems in IGD subjects. [ABSTRACT FROM AUTHOR]

Converging evidence has identified the imbalance between goal-directed systems and habitual systems in the addiction process. The thalamocortical loop plays an important role in the habitual/goal-directed system. However, little is known about the role of the thalamus in goal-directed and habitual systems in Internet gaming disorder (IGD) patients. This study investigated whether thalamocortical circuit was disrupted and how they affected goal-directed and habitual behaviors in IGD patients. This is a functional magnetic resonance imaging (fMRI) study. Twenty-five IGD patients and 25 matched recreational game users (RGUs) were scanned when they were in a resting state and were performing an instrumental learning task to obtain behavioral data related to habitual/goal-directed behavior. We used the whole-brain seed-based functional connectivity (FC) of the four thalamic nuclei (bilateral) and correlation analyses to examine the thalamocortical loop difference and relationship with habitual/goal-directed performance. Compared with RGUs, IGD patients demonstrated significantly increased FC between the left midline nucleus (MN) and the right postcentral gyrus (PCG), and between the pulvinar and medial frontal gyrus (MFG). Correlation results showed that within the IGD group, the correct response rates of the participants to inconsistent stimulus-result pairs were positively correlated with the FC between the pulvinar and MFG. Inhibition-control scores were negatively correlated with the FC between the left MN and the PCG. IGD patients showed disrupted thalamocortical communication that could further result in an imbalance between the goal-directed and habitual systems in IGD patients. These findings provide more information about the involvement of the thalamus in the pathophysiology of IGD, and as potential circuit-level biomarkers of IGD patients, these circuit alterations may be useful in treatment development and in monitoring treatment outcomes. [ABSTRACT FROM AUTHOR]

Abnormal interactions among addiction brain networks associated with intoxication, negative affect, and anticipation may have relevance for internet gaming disorder (IGD). Despite prior studies having identified gender-related differences in the neural correlates of IGD, gender-related differences in the involvement of brain networks remain unclear. One-hundred-and-nine individuals with IGD (54 males) and 111 with recreational game use (RGU; 58 males) provided resting-state fMRI data. We examined gender-related differences in involvement of addiction brain networks in IGD versus RGU subjects. We further compared the strength between and within addiction brain networks and explored possible relationships between the strength of functional connectivities within and between addiction brain networks and several relevant behavioral measures. The addiction brain networks showed high correct classification rates in distinguishing IGD and RGU subjects in men and women. Male subjects with versus without IGD showed stronger functional connectivities between and within addiction brain networks. Moreover, the strength of the connectivity within the anticipation network in male IGD subjects was positively related to subjective craving. However, female subjects with versus without IGD showed decreased functional connections between and within addiction brain networks. The strength of connectivity between the anticipation and negative-affect brain networks in female IGD subjects was negatively related to maladaptive cognitive emotion-regulation strategies. Addiction brain networks have potential for distinguishing IGD and RGU individuals. Importantly, this study identified novel gender-related differences in brain-behavior relationships in IGD. These results help advance current neuroscientific theories of IGD and may inform gender-informed treatment strategies. • Identified novel gender-related brain mechanisms in IGD. • Behavioral measures/correlates differed between male and female IGD subjects. • Addiction brain networks have potential for distinguishing IGD and RGU individuals. [ABSTRACT FROM AUTHOR]

Individuals with internet gaming disorder (IGD) usually report a higher sense of loneliness. Although studies have suggested a key role of the prefrontal cortex-based resting-state functional connectivity (rsFC) in both IGD and loneliness, the potential mechanism between IGD and loneliness remains unclear. Fifty-seven IGD and 81 matched recreational internet gamer users (RGU) underwent resting-state fMRI scans. The UCLA loneliness scale was used to measure loneliness. We first explored the brain areas that are both associated with loneliness and IGD severity. Then, the neuroimaging findings were extracted to test whether the rsFC of these brain regions moderates the relationship between IGD and loneliness. We observed reduced rsFC between the left dorsolateral prefrontal cortex (DLPFC) and the left precentral and the postcentral gyri and the supplementary motor area (SMA), which also correlated with increased IAT (Young''s internet addiction test) scores. More importantly, the rsFC of the DLPFC-precentral gyrus and the DLPFC-postcentral gyrus moderated the relationship between IGD severity and loneliness scores. Additionally, we also found that the rsFC of the left DLPFC-precentral gyrus, the DLPFC-postcentral gyrus and the right DLPFC-SMA moderated the relationship between self-reported gaming craving and the UCLA scores. The current study confirmed the role of the DLPFC in reward control (game craving) and emotion regulation (loneliness). Additionally, the rsFC of the prefrontal cortex-supplementary motor area moderates IGD and loneliness. These findings provide valuable understanding of the two-way relationship between IGD and loneliness. • The rsFC of DLPFC with the SMA that correlated with IGD severity (IAT). • The rsFC moderated the relationship between IGD severity and loneliness. • The rsFC moderated the relationship between craving and the UCLA scores. [ABSTRACT FROM AUTHOR]