Imbalanced functional link between executive control network and reward network explain the online-game seeking behaviors in Internet gaming disorder

Literatures have shown that Internet gaming disorder (IGD) subjects show impaired executive control and enhanced reward sensitivities than healthy controls. However, how these two networks jointly affect the valuation process and drive IGD subjects' online-game-seeking behaviors remains unknown. Thirty-five IGD and 36 healthy controls underwent a resting-states scan in the MRI scanner. Functional connectivity (FC) was examined within control and reward network seeds regions, respectively. Nucleus accumbens (NAcc) was selected as the node to find the interactions between these two networks. IGD subjects show decreased FC in the executive control network and increased FC in the reward network when comparing with the healthy controls. When examining the correlations between the NAcc and the executive control/reward networks, the link between the NAcc - executive control network is negatively related with the link between NAcc - reward network. The changes (decrease/increase) in IGD subjects' brain synchrony in control/reward networks suggest the inefficient/overly processing within neural circuitry underlying these processes. The inverse proportion between control network and reward network in IGD suggest that impairments in executive control lead to inefficient inhibition of enhanced cravings to excessive online game playing. This might shed light on the mechanistic understanding of IGD

Hypofrontality in Schizophrenia. A meta-analysis of functional imaging studies

The definitive version is available at www.blackwell-synergy.com '--Copyright Blackwell PublishingObjective: Hypofrontality is not a well-replicated finding in schizophrenia either at rest or under conditions of task activation. Method: Studies comparing whole brain and frontal blood flow/ metabolism in schizophrenic patients and normal controls were pooled.Voxel-based studies were also combined to examine the pattern of prefrontal activation in schizophrenia. Results: Whole brain flow/metabolism was reduced in schizophrenia to only a small extent.Restin g and activation frontal flow/metabolism were both reduced with a medium effect size.Duration of illness significantly moderated resting hypofrontality, but the moderating effects of neuroleptic treatment were consistent with an influence on global flow/metabolism only.Pooling of voxel-based studies did not suggest an abnormal pattern of activation in schizophrenia. Conclusion: Meta-analysis supports resting hypofrontality in schizophrenia.Task-activated hypofrontality is also supported, but there is little from voxel-based studies to suggest that this is associated with an altered pattern of regional functional architecture.Peer reviewe