We recruited forty-eight individuals with IGD and forty-six recreational internet game users (RGUs) as a control group in this study. fMRI data were collected when they were finishing a value-matching delayed discount task (DDT), which included easy and hard decisions judging based on the indifference points of every participant. The correlations between brain responses during DDT and IGD severity and the effective connectivity between brain regions were calculated.
Compared to RGUs, IGD subjects showed enhanced activation in the orbitofrontal cortex (OFC) when facing hard choices, and this feature was associated with IGD severity. In addition, individuals with IGD showed increased effective connectivity from the OFC to the dorsolateral prefrontal cortex and the OFC to the occipital lobe and decreased effective connectivity from the occipital lobe to the OFC.
The current study showed that the abnormal activation in the OFC was associated with IGD severity and higher OFC-DLPFC/OFC-occipital lobe effective connectivity and lower occipital lobe-OFC effective connectivity when individuals with IGD faced different choices in the DDT. These findings suggest the neural mechanisms of impulsive decision-making in individuals with IGD due to dysfunction with subjective evaluation and dysfunction of the connection with the executive control system.
方法:在这项研究中,我们招募了48名IGD患者和46名休闲网络游戏用户(RGU)作为对照组。功能磁共振成像数据是在他们完成价值匹配延迟折扣任务(DDT)时收集的,其中包括根据每个参与者的冷漠点做出简单和艰难的决定。计算了DDT和IGD严重程度期间的大脑反应与大脑区域之间的有效连接之间的相关性。
结果:与RGU相比,IGD受试者在面对艰难的选择时,在眶额皮质(OFC)显示出增强的激活,此特征与IGD严重程度相关。此外,IGD患者从OFC到背外侧前额叶皮质和OFC到枕叶的有效连通性增加,从枕叶到OFC的有效连通性降低.
结论:目前的研究表明,当IGD患者在DDT中面临不同的选择时,OFC的异常激活与IGD严重程度和较高的OFC-DLPFC/OFC-枕叶有效连接和下枕叶-OFC有效连接有关。这些发现表明,由于主观评估的功能障碍以及与执行控制系统的联系的功能障碍,IGD患者的冲动性决策的神经机制。