| Objective:Internet gaming disorder(IGD) is the most prevalent form of internet addiction disorder in Asia, which has become a serious mental health issue. Reduced decision-making ability was reported as main behavioral impairments in individuals with IGD. However, it is not clear to date how the risk level modulates the brain activity during decision-making process in the IGD individuals. Thus, in this study, we investigated whether the modulation by the risk level on the brain activation during decision-making process and decision making based on outcomes is altered in the IGD adolescents compared to the HCs. This study would contribute to the understanding of the neuromechanisms of the risk-taking and impulsive behaviors in IGD adolescents.Methods:In this study, 24 adolescents with IGD and 24 healthy controls(HCs) without IGD were recruited and the Balloon Analog Risk Task(BART) was used in a functional magnetic resonance imaging(fMRI) experiment to evaluate the modulation by the risk level(the probability of balloon explosion) on the brain activity during the risky decision-making effected by prior outcomes in the IGD adolescents. Functional MRI data preprocessing were conducted using SPM8. The general linear model(GLM) was used for voxel-based individual data analysis. Firstly, the GLM included three types of events resulted from a button press: an inflation of balloon, a win outcome, or a loss outcome. The risk level associated with each inflation was also entered into the model as a linear parametric modulation of the balloon inflation regressor. The analyses were conducted by ANOVA on the risk-related contrasts with full factorial in the whole brain level. Secondly, four regressors were included in the GLM: win outcome, inflation after win, loss outcome, and inflation after loss, and the risk level was also entered into the model. The analyses were conducted by ANOVA with full factorial in the whole brain level, too. All multiple comparisons were corrected by AlphaSim. The brain regions with interactive effect were established as region of interests(ROIs). The correlation between the average ? estimates within ROIs and Barratt impulsiveness scale-11(BIS-11) scores, Young's online internet addiction test(IAT) scores were examined by Pearson's correlation analysis in the IGD group with SPSS 21.0.Results:(1) A significant interactive effect on the activation of the right dorsolateral prefrontal cortex(DLPFC) and the left cerebellum. The post-hoc t-test revealed that the modulation by the risk level on the activation of the right DLPFC and the left cerebellum was reduced during the active BART in the IGD group compared to the HCs(P < 0.05, AlphaSim correction). There was a significant negative correlation between the risk-related DLPFC activation during the active BART and the Barratt impulsivity scale(BIS-11) scores which were significantly higher in the IGD group compared to the HCs(P < 0.05).(2) In the active task, during a series of decision making based on the outcomes of previous choices, the covariance between the risk level and the activations of the bilateral ventral medial prefrotal cortex(VMPFC), the left inferior frontal cortex, the right ventral striatum, the left hippocampus/parahippocampus, the right inferior occipital gyrus/fusiform and the right inferior temporal gyrus has interaction effects of group by outcomes. The post-hoc t-test showed the covariance between the risk level and brain activation significantly increased in the IGD group compared with the HCs after receiving loss outcome(P < 0.05). However, there was no difference between groups after receiving win outcome.Conclusion:(1) In the IGD group, the modulation by the risk level on the activation of the right DLPFC was reduced, and there was a significant negative correlation between the risk-related DLPFC activation during the active BART and the BIS scores which were significantly higher in the IGD group compared to the HCs. Our study demonstrated that, as a critical decision making-related brain region, the right DLPFC is less sensitive to the risk in the IGD adolescents compared to the HCs, which may contribute to the higher impulsivity and disadvantageous decision-making in the IGD adolescents.(2) The covariance between the risk level and brain activation of the bilateral VMPFC, the left inferior frontal cortex, the right ventral striatum, the left hippocampus/parahippocampus, the right inferior occipital gyrus/fusiform and the right inferior temporal gyrussignificantly increased in the IGD group compared with the HCs after receiving loss outcome. Our results indicated that the negative outcome affected risk-related brain activity in the IGD adolescents, which suggested that the IGD adolescents with high impulsivity needed to recruit more brain resources related to the value evaluation, reward and emotion processing to maintain the normal performance under higher risky conditions during decision making. |
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